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Haryana State Board HBSE 7th Class Science Solutions Chapter 2 Nutrition in Animals Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 2 Nutrition in Animals

HBSE 7th Class Science Nutrition in Animals Textbook Questions and Answers

Question 1.
Fill in the blanks:
(a) The main steps of digestion in humans are …………… , …………… , …………… , …………… , and …………… .
(b) The largest gland in these human body is …………… .
(c) The stomach releases hydrochloric acid and …………. juices which act on food.
(d) The inner wall of the small intestine has many finger-like outgrowths called …………… .
(e) Amoeba digests its food in the …………… .
Answer:
(a) ingestion, digestion, absorption, assimilation, egestion
(b) liver
(c) digestive
(d) villi
(e) food vacuole.

Question 2.
Mark T if the statement is true and F if it is false:
(а) Digestion of starch starts in the stomach.
(b) The tongue helps in mixing food with saliva.
(c) The gall bladder temporarily stores bile.
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time.
Answer:
(a) False
(b) True
(c) False and
(d) True.

Question 3.
Tick (✓) mark the correct answer in each of the following:
(a) Fat is completely digested in the:
(i) stomach
(ii) mouth
(iii) small intestine
(iv) large intestine.
Answer:
(iii) small intestine.

(b) Water from the undigested food is absorbed mainly in the:
(i) Stomach
(ii) food pipe
(iii) small intestine
(iv) large intestine.
Answer:
(iv) large intestine.

Question 4.
Match the items of column I with those given in column II:

Answer:

Question 5.
What are Villi? What is their location and function?
Answer:
Villi are the finger like structures which are the form of internal layer. They are situated in the stomach.
Functions:
(i) Villi provides space for food.
(ii) Digestive juice is secreted out from the digestive glands present in the Villi in the embedded form.
(iii) The food is grinded by the contraction and expansion of Villi.

Question 6.
Where is the bile produced? Which component of the food does it digest?
Answer:
The liver secretes bile juice that is stored in a sac called the gall bladder. The bile plays an important role in the digestion of fats.

Question 7.
Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.
Answer:
The grass is rich in cellulose, a type of carbohydrate. Many animals, including humans, cannot digest cellulose. The cellulose can be digested by ruminants but not by humans because they have a large sac-like structure between the small intestine and large intestine. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.

Question 8.
Why do we get instant energy from glucose?
Answer:
We get instant energy from glucose, because in the cells, glucose breaks down with the help of oxygen into carbon dioxide and water and energy is released.

Question 9.
Which part of the digestive canal is involved in:
(i) absorption of food
(ii) chewing of food
(iii) killing of bacteria
(iv) complete digestion of food
(v) formation of faeces.
Answer:
(i) small intestine
(ii) buccal cavity
(iii) stomach
(iv) small intestine
(v) large intestine.

Question 10.
Write one similarity and one difference between the nutrition in Amoeba and human beings.
Answer:
Similarity: In both, the process of digestion involves ingestion, digestion, absorption, assimilation and egestion.
Difference: In Amoeba, the enzymes secreted by the call cytoplasm digest the ingested food.
In man, there are special organs for the digestion of food. The food passes through the alimentary canal. Here several digestive enzymes are secreted. These enzymes break the complex food materials into simpler ones.

Question 11.
Match the items of column 1 with suitable items in column II:

Answer:

Question 12.
Label following figure of the digestive system.

Answer:

Question 13.
Can we survive only on raw, leafy vegetables/grass? Discuss.
Answer:
No, we cannot survive only on raw, leafy vegetables/grass, Discuss of this topic in your class and ask to your teacher.

Extended Learning Activities And Project

Question 1.
Visit a doctor and find out:
(i) Under what conditions does a patient need to be on a drip of glucose?
(ii) Till when does a patient need to be given glucose?
(iii) How does glucose help the patient recover?
Write the answers in your notebook.
Answer:
Do yourself. Consult your family doctor and ask these Questions.

Question 2.
Find out what Vitamins are and get the following information.
(i) Why are Vitamins necessary in the diet?
(ii) Which fruits or vegetables should be eaten regularly to get Vitamins?
Write a one-page note on the information collected by you. You may take help of a doctor, a dietician, your teacher or any other person, or any other source.
Answer:
You have learnt about vitamins in class VI (chapter 2 – components of food).

Question 3.
Collect data from your friends, neighbours and classmates to find out about “milk teeth”. Tabulate your data. One way of doing it is given below:

Find out from at least twenty children and find the average age at which children lose the milk teeth. You may take help of your friends.
Answer:
Do yourself. Take help to your classmates and friends.

HBSE 7th Class Science Nutrition in Animals Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Name the body parts that capture food in Hydra, Amoeba.
Answer:
Hydra-tentacles, Amoeba-Pseudopodia.

Question 2.
Name the important parts of the digestive system of human body.
Answer:
(i) Mouth with buccal cavity
(ii) Oesophagus
(iii) Stomach
(iv) Duodenum
(v) Small intestine
(vi) Large intestine
(vii) Anus.

Question 3.
Name three parts in which digestion takes place in the digestive system of human body.
Answer:
(i) Buccal cavity
(ii) Stomach
(iii) Small intestine with duodenum.

Question 4.
In which part of the digestive system absorption of water takes place?
Answer:
Absorption of water takes place in large intestine.

Question 5.
What are Villi?
Answer:
Villi are the finger like folds in the inner walls of stomach.

Question 6.
What is the fuel for energy production in cells?
Answer:
Carbohydrates acts as the fuel for energy.

Question 7.
Name Five steps in the process of nutrition.
Answer:
1. Ingestion
2. digestion
3. absorption
4. assimilation and
5. egestion.

Question 8.
In which part of the alimentary canal
(a) absorption of water takes place
(b) assimilation of digested food occurs?
Answer:
(a) Large intestine
(b) Small intestine.

Question 9.
In which two parts of man does much of the digestion take place?
Answer:
In stomach and small intestine much of the digestion take place.

Question 10.
What are pseudopodia?
Answer:
Amoeba constantly changes its shape and position. It pushes out one, or more finger-like projections, called pseudopodia or false feet for movement and capture of food.

Question 11.
Name the organ of the digestive system where digestion of food of all types takes place.
Answer:
Small Intestine.

Question 12.
Is the large intestine really large?
Answer:
No. The large intestine is wider and shorter than small intestine. It is about 1.5 metre in length.

Question 13.
Where does digestion start in humans?
Answer:
In humans, digestion starts in stomach.

Question 14.
Name the largest gland in the human body.
Answer:
Liver is the largest gland in the human body.

Question 15.
Name three ruminant animals.
Answer:
1. Cow
2. Buffalo and
3. Horse.

Question 16.
Define ruminants.
Answer:
Herbivores like cow, buffalo etc. first swallow the food without chewing it. After some time, they bring back the swallowed food to their mouth from the pouch of the stomach. Then they again grind the food well and swallow it. It is called chewing of the cud. These animals are known as ruminants.

Question 17.
What are incisors?
Answer:
Incisors are the flat front teeth. These have a sharp straight edge that help us to cut food and hence, they are also called cutting teeth. There are four incisors in each jaw.

Question 18.
What are canines?
Answer:
Canines are the pointed teeth present on either side of the incisors. These help us to tear the food and hence, they are called the tearing teeth. There are two such teeth in each jaw.

Question 19.
Define ingestion.
Answer:
Ingestion is the process by which food is taken by the organisms.

Question 20.
Define digestion.
Answer:
Digestion is the process of breaking down complex food molecules into similar molecules and is brought about with the help of special molecules called enzymes.

Question 21.
Define egestion.
Answer:
Egestion is the process by which undigested food is removed from the body.

Question 22.
Define absorption.
Answer:
The process by which the digested food molecules are taken up (or absorbed) by the intestine wall and sent to the circulatory system is called absorption.

Question 23.
What is assimilation?
Answer:
Assimilation is a process of conversion of absorbed food into body. For example, in man and other higher animals, the blood carries the food to different parts of the body for incorporation into cell components.

Question 24.
What is gall bladder?
Answer:
The liver secretes juices which help in digestion and are stored in a small bag called the gall bladder.

Question 25.
In which part of the digestive system and assimilation of food takes place?
Answer:
In human digestive system. Digestion takes place in buccal cavity, stomach and small intestine. Assimilation takes place in small intestine.

Question 26.
Write two functions of Villi.
Answer:
(i) Villi provides space for food.
(ii) Digestive juice is secreted out from the digestive glands present in the villi in the embedded form.

Question 27.
What is the function of oesophagus?
Answer:
No digestion takes place here. It only helps in pushing the food into stomach.

Question 28.
What is amylase?
Answer:
Saliva contains an enzyme called amylase. Amylase acts on starch and changes it into a sugar (called maltose).

Question 29.
Name the two processes of respiration.
Answer:
Inhalation and exhalation are the two processes of respiration.

Question 30.
Name the cells that carry water and food in the body of a green plant.
Answer:
Cells of Xylem vessels.

Short Answer Type Questions

Question 1.
How do the different animals procure food?
Answer:
Different organisms procure different methods. There are special structures in each organism for taking in food, for example, frog uses its sticky tongue to catch the prey. Butterfly has probosces (special mouth parts) to suck nectar from flowers. The housefly also lives on liquid food. It also has feeding tube to suck the liquid food. A spider spins a web to catch small insects. Human beings use hands to put their food in the mouth.

Question 2.
What are the stages in the process of Nutrition?
Answer:
The food taken into the body by an animal is processed further to derive nutrients from it. There are five stages in the processing of food in an animal.
These include:
(i) Ingestion
(ii) Digestion
(iii) Absorption
(iv) Assimilation
(v) Egestion.

Question 3.
“What do you understand by digestive enzymes?” How does amylase affect starch?
Answer:
Digestive enzymes are the special proteins secreted out in gastric glands, small intestine and in pancreas. Specific enzyme helps in digestion of specific food item.

Amylase is the enzyme secreted in the pancreatic juice which converts carbohydrates (Polysaccharides) starch into Maltose sugar (Disaccharides).

Question 4.
How does nutrition occur in amoeba?
Answer:Amoeba
constantly changes its shape and position. It pushes out one, or more finger-like projections, called pseudopodia or false feet for movement and capture of food.

Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle and engulfs it. The food becomes trapped in a food vacuole. Digestive juices are secreted into the food vacuole. They act on the food and break it down into simpler substances. The absorbed substances are used for growth, maintenance and multiplication. The undigested residue of the food is expelled outside by the Vacuole.

Question 5.
How does nutrition occur in paramecium?
Answer:
In paramecium, the food is ingested with the help of small hair-like structures present on the cell membrane. These are called the cilia. The food passes to oral groove from the cell membrane and then enters the mouth. From the mouth the food is taken inside the main body, where the food vacuole helps in its digestion with the help of enzymes. The undigested food is excreted with the help of contrectile vacuole.

Question 6.
Differentiate between absorption apd assimilation.
Answer:
Absorption:
It is a process by which digested food gets absorbed. The soluble food materials pass through the wall of digestive tract and reach the circulatory system or body fluid of an organism. In human beings and in other higher organisms, absorption takes place in the small intestine.

Assimilation:
It is a process of conversion of absorbed food into body. For example, in man and other higher animals the blood carries the food of different parts of the body for incorporation into cell components.

Question 7.
Write short note on small intestine.
Answer:
Small intestine is a long coiled tube. It also secretes a juice and digestion of all types of food is carried out here. As a result of digestion, food is converted into simple form, and glucose, amino acid and fatty acides etc. are formed. These end products are ready for absorption. Small intestine also absorbs the digested food and passes it on to the blood system. Thus, the nutrients are carried to all parts of the body.

Question 8.
What happens to the digested food in our bodies?
Answer:
Our body requires energy to carry out the various activities of life. We get this energy from the food we eat. This happens during respiration. The food which we eat is digested in the alimentary canal. But the alimentary canal alone does not require food. It must go to all parts of the body. The digested food is absorbed by the small intestine and passed on to the blood. Through the blood, the absorbed food is carried to all parts of the body.

Question 9.
Why is the process of excretion important for living organisms?
Answer:
In all the living beings the metabolic activities take palce within the body for getting energy. The remaining part of the food is called as the waste material which are harmful to the body. So to become healthy and for proper functioning it is essential to pass these wastes from the body.

Question 10.
What are the main organs of the digestive system in our body?
Answer:
The process of digestion starts in the mouth. From the mouth, the food passes through a food canal (called alimentary canal).
Alimentary canal is a long, muscular and coiled tube, it starts from the mouth and ends at anus.
The different organs of the alimentary canal are as follows:
1. Mouth and mouth cavity.
2. Oesophagus (gullet or food pipe)
3. Stomach.
4. Small intestine.
5. Large intestine.
6. Anus.

Associated with the alimentary canal are some glands. These are:
1. Salivary glands
2. Liver
3. Pancreas.
The alimentary canal along with the associated glands is called the digestive system.

Question 11.
Write the functions of tongue.
Answer:
Tongue, a muscular organ, is also important for eating and performs several functions:
(i) It helps in mixing the chewed food with saliva
(ii) Swallowing the food
(iii) The tongue tastes, as it has sense organs called the taste buds.
These buds distinguish four basic tastes-salty, sour, sweet and bitter. In addition, it helps us to speak.

Question 12.
What are salivary glands?
Answer:
There are three pairs of salivary glands in our mouth. A watery material called saliva is secreted by these glands. Saliva helps in the digestion of food. Saliva contains an enzyme called amylase (also called ptyalin). Amylase acts on starch and changes it into a sugar (called maltose). The sugar is sweet and soluble in water.

Question 13.
What is meant by excretion? Explain its need for the sustenance of the individual.
Answer:
Excretion is the passing out of the metabolic wastes from the body through special organs known as excretory organs. The excretory matter, if it is present in the body, will disturb the metabolic activities going on in different parts of the body and also become hurdle in the circulation. It will disturb metabolic activity in body. So it is necessary to excrete out all the metabolic wastes from the body.

Long Answer Type Questions

Question 1.
Name the different types of teeth in an adult man and state their functions. Also give a labelled diagram of different types of teeth.
Answer:
There are four main kinds of teeth in humans-incisors, canines, premolars and molars.

The front four teeth in each jaw are the incisors. They are flat and help in biting the food. On either side of the incisors are the canines. These are sharp and two in number in each jaw. They are meant for tearing the food. The premolars and molars are meant for grinding and crushing the food. Premolars are behind the canines, two in number on either side in each jaw.

Molars are behipd the preiholars. In an adult, they are six in number in each jaw, three each on either side of the premolars. In young people there are 8 molars in all. The second set of 4 molars appears at the age of eighteen or even later. These are called the wisdom teeth. Each jaw in an adult has 16 teeth, or 32 teeth in all.

Question 2.
Describe briefly the different stages involved in the process of nutrition.
Answer:
The different stages involved in the process of nutrition are:
1. Ingestion:
It is a process of taking in food. It differs from animal to animal, for example, frog uses its tongue to catch its prey, human beings hold food with hands and put it into their mouth, etc.

2. Digestion:
It is a process of breakdown of complex food materials such as carbohydrates, fats, proteins etc, into simpler forms. It is both a mechanical and a chemical process.

3. Absorption:
It is a process by which digested food gets absorbed. The soluble food materials pass through the wall of digestive tract and reach the circulatory system or body fluid of an organism. In human beings and in other higher organisms, absorption takes place in the small intestine.

4. Assimilation:
It is process of conversion of absorbed food into body. For example, in man and other higher animals, the blood carries the food to different parts of the body for incorporation into cell components.

5. Egestion:
It is the process by which the undigested food is eliminated from the body. In man and other organisms, it is carried out through the anus.

Question 3.
Name the things which help in physical and chemical digestion.
Answer:
The things which help in physical digestion are as follows:
(а) Tongue and Teeth: They masticate and chew the food. The tongue helps in this process.
(b) Villi of Stomach: By peristeltic movement villi help in mixing the digestive juices with the food.

The things which help in chemical digestion are as follows:
(а) Saliva: It contains ptyalin which convert carbohydrates of food into maltose sugar.
(b) Hydrochloric acid: It provides the acidic medium to the food.
Gastric Juice: It contains pepsin enzyme which converts protein into peptone.

(c) Pancreatic juice: It contains three enzymes.
Trypsin: Which converts peptone into amino acid.
Amylopsin: Which converts maltose sugar into sugar.
Stepsin or lypase: It converts fat into fatty acid and glycol.

(d) Intestinal juice: Which converts the remaining part of food into soluble form.

Question 4.
‘Excretion is a process to eliminate waste by products from the body’. Justify the statement.
Answer:
In all the living beings the biochemical reactions go on continuously which are commonly named as metabolism. It is of two types i.e., anabolism and catabolism. During anabolism the simple compounds combine together to form complex compounds while in catabolism the complex compounds are oxidised and convert into simple compounds and energy. These by products are waste and harmful substances. They are to be expelled out from the body.

If these wastes remain inside the body they will combine together to form other compounds which may be poisonous or more harmful to the body. They may become hurdle to the activities and also may cause death. So the catabolic by products should be passed out from the body. These products are called excretory matter and the organs through which they are expelled, are called excretory organs and the process is called as excretion.

Question 5.
What are the various components of blood? Give their functions.
Answer:
The various components along with their functions are as follows:
Blood Plasma: It is the liquid of the blood which carries food materials, water and other excretory matter to all parts of the body.
Corpuscles:
They are of the three following types:
1. Red Blood Corpuscles (R.B.C.): They carry oxygen to all cells of all parts of the body.
2. White Blood Corpuscles (W.B.C.): They are uninucleated and amoeboid in shape. They light against the disease germs.
3. Blood Platelets: They are spindle shaped and help in clotting the wounds.

Nutrition in Animals Class 7  HBSE Notes

• Animal nutrition includes nutrient requirement, mode of intake of food and its utilisation in the body.
• Digestion is the process of breaking down complex food molecules into simpler molecules and is brought about with the help of special molecules called enzymes.
• The human digestive system consists of the alimentary canal and secretory glands. It consists of the (i) buccal cavity, (ii) oesophagus, (iii) stomach, (iv) small intestine, (v) large intestine ending in rectum, and (vi) anus.
  → The main digestive glands which secrete digestive juices are (i) the salivary glands, (ii) the liver and (iii) the pancreas. The stomach wall and the wall of the small intestine also secrete digestive juices.
• Different organisms possess different structures for procuring food.
• Digestion is a complex process involving: (i) ingestion, (ii) digestion, (iii) absorption, (iv) assimilation and (v) egestion.
• Digestion of carbohydrates, like starch, begins in the buccal cavity. The digestion of protein starts in the stomach. The bile secreted from the liver, the pancreatic juice from the pancreas and the digestive juice from the intestinal wall complete the digestion of all components of food in the small intestine. The digested food is absorbed in the blood vessels in the small intestine.
• The absorbed substances are transported to different parts of the body. Water and some salts are absorbed from the undigested food in the large intestine.
• The undigested and unabsorbed residues are expelled out of the body as faeces through the anus.
• The grazing animals like cows, buffaloes and deer quickly swallow the grass and store it in a separate part of the stomach called rumen. Here the food gets partially digested and is called cud. But later the cud returns to the mouth in small lumps and the animal chews it. This process is called rumination and these animals are called ruminants.
• Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle and engulfs it. The food becomes trapped in a food vacuole.

Haryana State Board HBSE 7th Class Science Solutions Chapter 1 Nutrition in Plants Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 1 Nutrition in Plants

HBSE 7th Class Science Nutrition in Plants Textbook Questions and Answers

Question 1.
Why do organisms need to take food?
Answer:
Food is needed by all living organisms for four main purposes:
(i) An important function of food is to help a living organism to grow, if enough food is not given or it is not of the right kind, growth will not be sufficient or healthy.
(ii) Second important function of food is to provide energy. We need energy for doing physical work. We use more energy when we run than when we walk and less energy when we sleep. Energy is given by hidden materials present in our food.
(iii) Food is also needed by living beings for replacement and repairing their damaged body parts.
(iv) Food gives us resistance against diseases and protects us from infections.

Question 2.
Distinguish between a parasite and a saprotroph.
Answer:
Parasite:
The mode of nutrition in organisms which derive their food from the body of some other living organism is called parasite nutrition. Such organism are called parasite. Examples of parasites are Tapeworm, Roundworm, Malarial parasite, Cuscutta, Puccinia (a fungus) etc.

Saprotroph:
The mode of nutrition in organisms which derive their food from the dead and decaying organic matter is called saprotroph nutrition and such organisms are called saprotroph. Examples of saprotrophs’^ire Mushrooms, Yeast and Bacteria.

Question 3.
How would you test the presence of starch in leaves?
Answer:
Starch Test:
(i) Take the green leaf to be tested.
(ii) Boil it in water for 5 minutes.
(iii) Keep it in the 60% angle amyle alcohol at 60°C till it becomes colourless.
(iv) Take the colourless leaf out from alcohol and wash it with cold water.
(v)Pour few drops of dilute Iodine solution on the leaf. The leaf becomes very blue with the solution which proves the presence of starch in the leaf.

Question 4.
Give a brief description of the process of synthesis of food in green plants.
Answer:
The process by which the green plants synthesize their own food in the presence of Sunlight and chlorophyll by taking carbon dioxide from the atmosphere and water from the soil is known as photosynthesis. The process of photosynthesis can be summarised as given below:

Green plants require four things to prepare their own food. These are:
1. Carbon dioxide, absorbed from the atmosphere through stomata present on the leaf surface.
2. Water, absorbed from the soil, through the root system.
3. Chlorophyll, present in the leaf.
4. Light, coming from the sun.
During photosynthesis, food is synthesized.
Oxygen is released in the process.

Question 5.
Show with the help of a sketch that the plants are the ultimate source of food.
Answer:

Question 6.
Fill in the blanks:
(a) Green plants are called ………….. since they synthesise their own food.
(b) The food synthesised by the plants isstared as …………… .
(c) In photosynthesis solar energy is captured by the pigment called …………… .
(d) During photosynthesis plants take in ………. and release ……………. .
Answer:
(a) autotrophs
(b) solar enetgy
(c) chlorophyll
(d) carbon dioxide, oxygen.

Question 7.
Name the following:
(i) A parasite plant with yellow, slender, tubular stem.
(ii) A plant that has both* autotrophic and heterotrophic mode of nutrition.
(iii) The pores through which leaves exchange gases.
Answer:
(i) Cuscuta (Amarbet)
(ii) Pitcher plant
(iii) Stomata

Question 8.
Tick the correct answer:
(a) Amarbel is an example of:
(i) Autotroph
(ii) Parasite
(iii) Saprotroph
(iv) Host.
Answer:
(iii) Parasite.

(b) The plant which traps arid feeds on insects is:
(i) Cuscuta
(ii) China rose
(iii) Pitcher plant
(iv) Rose.
Answer:
(iii) Pitcher plant.

Question 9.
Match the items given in column I with those in Column II:

Answer:

Question 10.
Mark ‘T’ if two Statement is true and ‘F’ if it is False.
(i) Carbon dioxide is released during photosynthesis.
(ii) Plants which synthesise their food themselves are called saprotrophs.
(iii) The product of photosynthesis is not a protein.
(iv) Solar energy is converted into chemical energy during photosynthesis.
Answer:
(i) False
(ii) False
(iii) False
(iv) True.

Question 11.
Choose the correct option from the following:
Which part of the plant gets carbon dioxide from the air for photosynthesis?
(i) Root hair
(ii) Stomata
(iii) Leaf veins
(iv) Sepals.
Answer:
(ii) Stomata.

Question 12.
Choose the correct option from the; following:
Plants take carbon dioxide from the atmosphere mainly through their:
(i) Roots
(ii) Stem
(iii) Flowers
(iv) Leaves.
Answer:
(iv) Leaves.

Extended Learning – Activities and Projects

Question 1.
Project
Take a potted plant with broad leaves. Take a strip of black paper and cut out a small square in its centre. Cover a part of a leaf with this paper
and secure it the occurrence of photosynthesis

with paper clips. Keep the plant in the sunlight for 2-5 days. Observe the difference in the colour of the covered and the uncovered portions on the leaf. Perform iodine test on leaf. Did the two parts show any difference in results? Remove the strip and expose the covered part to the sunlight for 2-3 days and do the iodine test again. Describe your observations.
Answer:
Do yourself.

Question 2.
Visit a green house if there is one near your place. Observe how they raise plants. Find out how they regulate the light, water and carbon dioxide.
Answer:
Do yourself. Take the help of your teacher.

Question 3.
Try growing a sweet potato just in water. Describe your experiment and observations.
Answer:
Do yourself. Take the help of your teacher.

HBSE 7th Class Science Nutrition in Plants Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Why do all living organisms need food?
Answer:
All living organisms need food for getting energy for doing physical work.

Question 2.
Define the term Nutrition.
Answer:
The process of taking or consuming and utilising food is called nutrition.

Question 3.
Define Photosynthesis?
Answer:
The process by which the green plants prepare food using carbon dioxide and water in the presence of chlorophyll and light is called photosynthesis.

Question 4.
Mention the role of chlorophyll in photosynthesis.
Answer:
The leaves have a green pigment called chlorophyll. It helps leaves to capture the energy of the sunlight. Without chlorophyll, photosynthesis will not tajte place.

Question 5.
Plants make food from water and carbon dioxide. What else is needed?
Answer:
Chlorophyll and sunlight are also needed to the plant for photosynthesis.

Question 6.
What would happen if there are no green plants on the earth?
Answer:
In the absence of green plants there will not be any living being.

Question 7.
What is the purpose of starch test?
Answer:
The confirmation of the presence of starch in the green plants also confirms that photosynthesis has taken place in the plant.

Question 8.
Name three Carnivorous animals.
Answer:
(a) Lion
(b) Tiger
(c) Leopard.

Question 9.
Name three Omnivorous animals.
Answer:
(a) Dog
(b) Cat
(c) Crow.

Question 10.
Name three Herbivorous animals.
Answer:
(a) Rabbit
(b) Deer
(c) Cow.

Question 11.
Name two Insectivorous plants.
Answer:
(a) Aldrovenda
(b) Sundew.

Question 12.
Write chemical reaction that takes place during photosynthesis.
Answer:

Question 13.
Which are the raw materials required for photosynthesis?
Answer:
The process of photosynthesis requires four raw materials:
1. Carbon dioxide
2. Water,
3. Chlorophyll
4, Light.

Question 14.
Why are green plants called autotrophs?
Answer:
Green plants can prepare their own food using inorganic substances from the environment. Hence they are called autotrophs.

Question 15.
What are heterotrophs?
Answer:
Human beings and other animals depend on plants for food. They cannot make their own food. They are called the heterotrophs.

Question 16.
What is the mode of nutrition in plants different from that of the animals?
Answer:
In plants the nutrition is autotrophic type in which anabolism takes place. While in animal, they are heterotrophs where catabolism takes place.

Short Answer Type Questions

Question 1.
‘All animals depend upon plants for food’. Justify the statement.
Answer:
Green parts of the plants have the ability to prepare their own food which is stored in their various parts. All the animals do not have such property. So they depend on plants for their food directly or indirectly.

Question 2.
Differentiate between autotrophic and heterotrophic nutrition.
Answer:

Question 3.
Differentiate between carnivores, Herbivores and Omnivores.
Answer:
Carnivores: Animals like lion, tiger, snake and leopard that depend on other animals for their food are called carnivores.
Herbivores: Animals like cow, goat, horse, sheep, deer and elephant that depend on plants for their food are called herbivores.
Omnivores: Omnivores are those which depend on both plants and animals for food, e.g. man, pig, hen, bear, crow etc.

Question 4.
Differentiate between saprophytes and epiphytes.
Answer:
Saprophytes: These are the organisms that depend upon dead and decaying matter for food e.g., Monotropa (a bacteria) etc. These grow during or after the rainy season.
Epiphytes: These grow on the trees but only for support. They possess green leaves and can prepare their own food by absorbing moisture from the atmosphere. They have special roots called the aerial roots for this purpose e.g. orchids.

Question 5.
What do you understand by parasite, saprophyte and symbiosis? Give one example for each.
Answer:
Parasites: Such living organisms are those which depend on other living beings for their food. They may also depend on host not only for food but also for shelter too. e.g., Lice, Leech, Bed bug.
Saprophytes: Such organisms are those which take the dead and decayed organic substances in the form of their food e.g., kite.
Symbiosis: It is the phenomenon in which two plants live together in such a way that both are beneficial for each other, e.g., Rhizobium bacteria live in the nodules of Leguminous plants.

Question 6.
Some plants are both parasite and saprophyte. Explain with examples.
Answer:
There are some plants which survive like parasite as well as saprophyte. For example, Lichen. In lichen algae which is green in colour and lives on the upper side of the plant in the sun and prepares its own food during photosynthesis. The lower part of lichen in fungus which is saprophyte in nature. Both live together in it.

Long Answer Type Questions

Question 1.
Describe an experiment to prove that chlorophyll is necessary for photosynthesis.
Answer:
1. Pluck one or two leaves from Croton and Coleus plant in the evening so that they have synthesised starch.
2. Make an outline sketch of the leaf to mark green and non-green areas of the leaf.
3. Boil the leaf in alcohol over a water bath till the chlorophyll and other pigments are washed out.

4. Now keep the leaf in a petridish and add sufficient amount of iodine solution over the leaf.
Only the green portion of the leaves turn blue-black showing the presence of starch in that region, As the green portion contained chlorophyll it could photosynthesise thereby forming starch. The non-green portion of the leaf does not have chlorophyll, which is essential for phtosynthesis.

Question 2.
Describe the factors affecting the process of photosynthesis.
Answer:
Factors affecting the process of Photosynthesis:
1. Light: It is essential for the process of photosynthesis. An increase in the intensity of light increases the rate of photosynthesis.
2. Carbon dioxide: It is the source of carbon for the synthesis of organic compounds formed in, the plant.
3. Water: It is also very important for the process of photosynthesis. Lack of water decreases the rate of photosynthesis.
4. Temperature: The optimum temperature required by most of the plants for photosynthesis is 350°C.
5. Chlorophyll: It is indispensable for the process of photosynthesis. Photosynthesis does not occur in the plants that lack chlorophyll.

Question 3.
Describe an experiment to prove that light is necessary for photosynthesis.
Answer:
1. Destarch the leaves of a potted plant by placing them in total darkness for about 24-48 hours.
2. Cover tightly one of the leaves with a leaf clasp or a strip of black paper on both the surface of the leaf. Use clips or cellotape to fix the black paper.
3. Put the experimental set up in sunlight for a few hours.

4. After that pluck the leaf that was covered with black paper or leaf clasp.
5. Test the leaf for the presence of starch by boiling it in alcohol over a water bath and then putting iodine solution over it.
The part of the leaf that was covered with black paper or leaf clasp did not get sunlight and thus no photosynthesis could occur in that region, hence, starch was not formed.
The part of the leaf that was exposed to sunlight could photosynthesise and so starch was formed in that region of leaf. This shows that light is essential for the process of photosynthesis.

Nutrition in Plants Class 7  HBSE Notes

1. Carbohydrates, proteins, fats, vitamins and minerals are components of food. These components of food are necessary for our body and are called nutrients.
2. Nutrition is the mode of taking food by an organism and its utilization by the body.
3. The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic (auto = self; trophos = nourishment) nutrition. Green plants are autotrophs.
4. Animals and most other organisms take in ready-made food prepared by the plants. They are called heterotrophs (heteros = other).
5. (a) The process by which green plants prepare their own food is called photosynthesis.

(b) Photosynthesis can be summarized as follows:

(c) Photosynthesis takes place mostly in green leaves which contain green pigment, Chlorophyll inside Chloroplasts.
(d) Gaseous exchange in the leaves takes place through tiny pores called stomata
6. The mode of nutrition in organisms which derive their food from the dead and decaying organic matter is called saprophytic nutrition and such organisms are called
saprophytes.
7. The mode of nutrition in organisms which derive their food from the body of some other living organism is called parasitic nutrition. Such organisms are called parasites and other organism, from wlWh the food is derived by the parasite, is called the host.

8. In,sect,ivores are the green plants growing in marshy areas. They obtain their nutrition partly from the soil and atmosphere and partly from the insects, e.g,, pitcher plant, venus fly-trap, sundew plant and bladderwort.
9. Some organisms live together and share shelter and nutrients. This is called symbiotic relationship. For example, certain fungi live in the roots of trees. The tree provides nutrients to the fungus and, in return, receives help from it to take up water and nutrients from the soil. This association is very important for the tree.
10. In a lichen, algal and fungal partners live together and both are mutually beneficial. Algal component of a lichen is autotrophic. It provides food material to the fungal component in the lichen. In return, the fungus (heterotroph) provides shelter, water and minerals to the alga.

Haryana State Board HBSE 6th Class Science Solutions Chapter 9 The Living Organisms and their Surroundings Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 9 The Living Organisms and their Surroundings

HBSE 6th Class Science The Living Organisms and their Surroundings Textbook Questions and Answers

Exercises

Question 1.
What is a habitat?
Answer:
The place where organisms live is called a habitat. When they live in water, it is known as an aquatic habitat or when they live on land it is known as land or terrestrial habitat. Habitat mean a dwelling place or home. Similar animals and plants may share the same habitat.

Question 2.
How are cactus adapted to survive in a desert?
Answer:
Desert plants lose very little water through transpirations. Cactus is a desert plant. The leaves of cactus plant are modified into spines. This helps in reducing loss of water through transpiration. The leaf like structure in a cactus is infact, its stem. Photosynthesis in cactus is usually carried out by the stems. Its stem is also covered with a thick waft cuticle/layer which helps to retain water. The root of cactus plant go very deep into the soil to absorb water. In this way we can say that cactus plant adapted to survive in the desert.

Question 3.
Fill up the blanks:
(a) The presence of specific features which enable a plant or an animal to live in a particular habitate, is called …………… .
(b) The habitats of the plants and animals that live, on land are called …………. habitat.
(e) The habitats of plants and animals that live in water are called ………… habitat.
(d) Soil, water and air are the ………… factors of a habitat.
(e) Changes in our surroundings that make us respond to them,, are called …………… .
Answer:
(a) Adaptation
(b) Terrestrial
(c) Aquatic
(d) Abiotic
(e) Stumuli.

Question 4.
Which of the things in the following list are non-living?
Plough, Mushroom, Sewing Machine, Radio, Boat, Water hyacinth, Earthworm.
Answer:
The non-living things are Plough, Sewing Machine, Radio, Boat.

Question 5.
Give an example of a non-living thing. Which shows any two characteristics of living things.
Answer:
Clouds in the sky. They show two living characteristics:
(i) They grow in size.
(ii) They move from one place to another place.

Question 6.
Which of the non-living things listed below, were once part of a living thing:
Butter, leather, soil, wool, electric bulb, cooking oil, salt, apple, rubber.
Answer:
Butter, leather, wool, cooking oil, apple.

Question 7.
List the common characteristic of the living things.
Answer:
Characteristics of the living things are as follows:
(i) All living things need food.
(ii) All living things show growth.
(iii) All living things respire.
(iv) They respond to stumuli.
(v) They excrete.
(vi) All living things reproduce.
(vii) They show movement;

Question 8.
Explain why speed is important for survival in the grasslands for animals that live there.
Answer:
There are few trees or places for animals to hide in the grassland habitats. The animals like lion or tiger prey other animals such as deer. The deer have very fast running speed to help them to run away from the predator’s speed is important for their survival in grassland habitats.

HBSE 6th Class Science The Living Organisms and their Surroundings Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Name two xerophytic plants.
Answer:
(i) Cactus
(ii) Zizyphus (her)
(iii) Babool.

Question 2.
Give two examples of hydrophyte.
Answer:
(i) Lotus
(ii) Water lily.

Question 3.
Give names of two terrestrial plants.
Answer:
(i) Neem
(ii) Mango.

Question 4.
Write the names of two animals which have different kinds of cover on their bodies?
Answer:
(i) Fish
(ii) Snakes.

Question 5.
What is the food of fishes?
Answer:
Micro plants and aquatic insects.

Question 6
Name one animal which lives in water as well as on land.
Answer:
Frog.

Question 7.
Give two examples of noctural animals.
Answer:
(i) Bat
(ii) Owl
(iii) Cockroach

Question 8.
Define habitat.
Answer:
The place where a plant or an animal lives in its own kind of home.

Question 9.
Where will you find the birds?
Answer:
On the branches of trees.

Question 10.
Name three desert animals.
Answer:
(i) Camel
(ii) Snake
(iii) Lizard.

Question 11.
What are the aquatic organisms?
Answer:
The plants and animals which can live only in water.

Question 12.
List two living organisms in a pond.
Answer:
(i) Frog
(ii) Fish.

Question 13.
Name three non-living things in a pond.
Answer:
(i) Water
(ii) Mud
(iii) Air.

Question 14.
Which is a special terrestrial habitat?
Answer:
Mountain is a special terrestrial habitat where temperature is very low and land is covered with snow.

Question 15.
What type of plants are found at higher altitude?
Answer:
At higher altitude plant species like grasses, mosses, and lichens generally grow.

Question 16.
What are biotic components?
Answer:
Plants and animals are biotic components.

Question 17.
What are abiotic components?
Answer:
Water, air, heat, light and soil are abiotic components.

Question 18.
Why are plants called autotrophs?
Answer:
Plants prepare their own food by the process of photosynthesis. So they are called autotrophs.

Question 19.
Name one animal which does not have eyes.
Answer:
Amblyopsis.

Question 20.
Name two animals which have reduced eyes.
Answer:
(i) Proteus and (it) Cave-dewelling fish.

Question 21.
Name one adaptation of a desert plant.
Answer:
Leaves and stem become thick and store water.

Question 22.
Where does penguin live?
Answer:
Penguin lives in very cold places.

Question 23.
Where do we get w ater?
Answer:
We get water from ponds, lakes, rivers and oceans.

Question 24.
Name two animals found at the bottom of the sea.
Answer:
Corals, star fish and urchins.

Question 25.
Why is carbon dioxide necessary for plants?
Answer:
Carbon dioxide is essential for preparing their food.

Question 26.
What is one harmful effect of moving air?
Answer:
It transports harmful bacteria and spores of disease-causing fungi.

Question 27.
How are animals and plants related?
Answer:
They are related through food chain.

Question 28.
How does soil help plants?
Answer:
Soil provides solid support to plants for their growth.

Short Answer Type Questions

Question 1.
What do you mean by noctural animals?
Answer:
Those animals which remain active during night and feed during night but take rest during day time are known as noctural animals. Examples bat, owl etc.

Question 2.
What do you mean by diurnal animals.
Answer:
Those animals which remain active during day time and rest at night are known as diurnal animals. Examples: Birds, Man etc.

Question 3.
Differentiate between terrestrial and aquatic organisms.
Answer:
Table 1

Question 4.
Differentiate between autotrophs and heterotrophs.
Answer:
Table 2

Question 5.
How do plants obtain their food?
Answer:
Plants prepare their own food by the process of photosynthesis, with the help of carbon dioxide, water and presence of sunlight. They obtain water and minerals from the soil by their roots.

Question 6.
Give examples of water and terrestrial habitats.
Answer:
Ponds, river, lakes and oceans are examples of aquatic habitats and water is a medium Forest is an example of terrestrial habitat. Deserts, tea garden and mountains are also terrestrial habitats.

Question 7.
How can you say that mountain is a special terrestrial habitat?
Answer:
Mountain is a special terrestrial habitat because at mountain tempera-ture is very low and most of the areas are covered by snow. Plants like grasses, mosses and lichens generally grow there. Animals like snow-bear, water fowl and musk deer are found in this habitat. Therefore, we can say that mountain is a special terrestrial habitat.

Question 8.
What are the biotic components?
Answer:
Plants and animals are part of biotic components. In addition, there are small organisms like bacteria and fungi in the habitat, which cannot be seen with naked eyes. These are called micro-organisms. They are also a part of biotic components of different habitat.

Question 9.
Name abiotic components.
Answer:
Soil, water and stones are non-living. They are abiotic components. Air, heat, light are also a part of abiotic components.

Question 10.
How do plants prepare their own food?
Answer:
Plants prepare their own food. They use water, carbon dioxide, and sunlight to prepare their own food by the process of photosynthesis, so they are called autotrophs. During this process, they release energy.

Question 11.
Light is necessary for plants and animals. Why?
Answer:
Plants and animals cannot survive without light. Plants prepare their own food in the presence of sunlight and animals get food from plants. They totally depend on plants for their food. So sunlight is essential for the survival of the biotic components. In the absence of light, plants becomes weak and delicate and their leaves become yellow. Plants cannot produce fruits and flowers.

Question 12.
What are the characteristics of xerophytes?
Answer:
The plants which grow in hot and dry places are called xerophytes. They have long and extensive roots, which goes deep in the soil in search of water. Leaves and stems of some plants become thick and store water. For example: Agane and opentia, their stems and leaves have thick cuticle layer, to prevent extensive loss of water by transpiration as in zinziphus (Ber) leaves also reduced and divided into small segments.

Question 13.
Why do desert animals have thick skin?
Answer:
Animals living in hot places, such as snakes, desert rats and lizards are not able to get sufficient water. So these animals have a thick skin, which prevents evaporation. Since they do not sweat, they can survive without water for a longer time.

Question 14.
How is camel adapted to live in desert?
Answer:
Camel lives in desert. It has long legs which help it to lift its body above the ground. Thus camel is able to avoid direct contact with the hot ground. The camel drinks water 50 litre or above in one time and store it in its body. So it lives without water for longer time. Its skin is also thick which prevents transpiration of water. Thus camel is suited to live in desert.

Question 15.
Define hydrophytes.
Answer:
Plant like hydrilla, water lily, water hyacinth and lotus grow in fresh water. Water growing plants may be submerged or partially submerged, floating and rooted in muddy soil. These plants are called hydrophytes.

Question 16.
What adaptations are found in hydrophytes?
Answer:
Hydrophytic plants are best suited to water by the presence of air storage parts in the stem and petioles to give buoyancy to plants for floating. Some rooted aquatic plants have the roots fixed in muddy water. In some plants, the floating leaves have waxy coating on the upper surface of the leaves and air cavity. For example lotus, water lily etc.

Question 17.
How fishes are adapted to live in water?
Answer:
Fishes are best suited to live in water. They have boat-like structure which help them in swimming in water. They have gills from which they get oxygen and food. The body of fishes contain different types of fins which help them for swimming in water. Fishes shape tapers which provide least resistance in swimming water.

Question 18.
How is soil important for plants?
Answer:
Top soil is most important for growing plants. Most of the organic matters, minerals, air and water are present in this layer. Water and air are very important for the growth of plants. Plant’s roots get oxygen for respiration. In this way, we can say that soil is important for plants.

Question 19.
How ddes air affect biotic components?
Answer:
Air is essential for the survival of plants and animals. Air contains oxygen and carbon dioxide. Animals cannot live without oxygen and plants cannot live without carbon dioxide. In the form of wind, air also affects plants and animals. Strong wind may break the branches of trees and uproot them. Some diseases caused by fungi and bacteria are spread by air.

Question 20.
How do plants balance oxygen and carbon dioxide in the atmosphere.
Answer:
Plants balance the oxygen and carbon dioxide ratio in the atmosphere. Plants release oxygen in the atmosphere during the process of photosynthesis and carbon dioxide released by animals is used by plants during the process of photo-synthesis for preparing their own food. In this way, plants maintain balance of oxygen and carbon dioxide in atmosphere.

Question 21.
Distinguish between aquatic and terrestrial habitate.
Answer:
The place where organisms live is called habitat. When they live in water, it is known as water or aquatic habitat. Water is a medium for aquatic habitat. When they live on land, it is known as land or terrestrial habitat and land is a medium for terrestrial habitat. Pond, oceans, rivers and lakes are examples of aquatic habitats and forests, deserts, tea gardens and orchards etc. are example of land habitats.

Question 22.
Explain, why is light essential for plants?
Answer:
Plants prepare their own food with the help of sunlight. Plants cannot survive without sunlight. All animals depend for their food on plants directly or indirectly. Indoor plants become weak without light. Their colour becomes yellow. They should shifted in the sunlight for sometime.

Long Answer Type Questions

Question 1.
How are biotic components related to abiotic components?
Answer:
Biotic components such as plants, animals and microorganisms, are influenced by abiotic components such as water, air, light, oxygen and temperature in different ways. Green plants prepare their own food and animals depend on plants for their food directly or indirectly. They provide shelter to animals. Thus all the organisms are related through food chain.

After death and decay of plants and animals, they are decomposed into simple minerals in the soil. These minerals are again used by plants through the roots. It shows that organisms do not live in isolation. They live in the company of other organisms and share common surroundings. Thus we see that all biotic components and the abiotic components such as air, water, light and soil are interrelated and interdependent on each other in the habitat.

Question 2.
How is fish adapted for aquatic life?
Answer:
(i) The body of a fish is spindle- shaped and streamlined which allows least resistance while moving in water.
(ii) The body is laterally compressed with a pointed head, body and’h tail.
(iii) The body is provided with the waterproof covering of scales.
(iv) Body is slimy because of mucous coating to reduce water tension.
(v) Fins are present for movement and swimming.

Question 3.
How is camel adapted to survive in a desert?
Answer:
Camel is adapted to live in a desert because of its following special features:
(i) A camel has long legs which help to keep its body away from the hot sand in the desert.
(ii) A camel can drink large amount of water when it is available and store it in the body.
(iii) A camel’s body is adapted to save water in the dry desert. A camel passes small amount of urine, its dung is dry and it does not sweat. Since a camel loses very little water from its body, it can live for many days without drinking water.
(iv) A camel’s hump has ‘fat’ stored in it. In case of emergency, a camel break down stored fat to obtain water.
(v) A camel has large and flat feet which help it to walk easily on soft sand by preventing it from sinking into the sand.

The Living Organisms and their Surroundings Class 6  HBSE Notes

• Habitat is a place where living organisms live.
• When plants and animals live in water, it is called aquatic habitat and when they live on land is called terrestrial or land habitat.
• Habitat comprises of two components that is biotic components which include living organisms such as plants, animals and micro-organisms and abiotic components which are non-living such as air, water, light and soil.
• Plants prepare their own food through the process of photosynthesis. Animals depend on plants for their food directly or indirectly.
• Abiotic components such as air, light, water, soil and temperature affect the distribution of plants and animals.
• These biotic and abiotic components are inter-related and inter-dependent on each other.
• Light is necessary for all living organisms. They cannot survive without light. Plants prepare their own food in the presence of sunlight by the process of photo-synthesis. All animals depend for their food on plants.
• Light also affects animals. Animals live in caves and burrows have very much reduced eyes. Amblyopsis, a cave dwelling fish, do not have eyes. Some animals such as bats and owls are active during night. These are called noctural animals.
• Temperature’s effects differ in different habitats. Different plants and animals find different temperature habitat. They suit themselves to adopt some modifications.
• The area where rain fall is very low, is called desert and plants growing there are called xerophyts. They have a long and extensive system. Their leaves are reduced. Camels live in, desert.
• Some animals live in very cold places. Yak and polar bear and penguins etc. lives in very cold places.
• The plants growing in water may be submerged or partially submerged. These plants are called hydrophytes. Plants are best suited to water by the presence of air storage parts in the stem and petioles to give a buoyancy to plant for floating. Such as water lily and Water Hyacinth etc.
• In ocean and sea water habitats, we observe phytoplanktons which include all floating plants such as algae and sea weeds. Large number of animals such as corals, star fish and urchins live in sea bottom. They adopt to live in water.
• Soil is another important abiotic factor which provides support to plants. Many animals live in soils. Soil contains air and water.
• Air is also very important abiotic factor. Plants and animals cannot survive without air.
• Biotic components such as plants, animals and microorganisms are influenced by abiotic factors or physical factors such as air, light and temperature in different ways.

Haryana State Board HBSE 6th Class Science Solutions Chapter 10 Motion and Measurement of Distances Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 10 Motion and Measurement of Distances

HBSE 6th Class Science Motion and Measurement of Distances Textbook Questions and Answers

Exercises

Question 1.
Give two examples each of modes of transport used on land, water and air.
Answer:
Modes of transport used are:
(i) Land: Buses, railways, cars etc.
(ii) Water: Boats, ships.
(iii) Air: Air planes, gas balloons, etc.

Question 2.
Fill in the blanks:
(i) One metre is ………….. cm.
(ii) Five kilometres is ………….. m.
(iii) Motion of a child on a swing is ……………. .
(iv) Motion of a needle of a swing machine is ………….. .
(v) Motion of a wheel of a bicycle is …………… .
Answer:
(i) 100
(ii) 5000
(iii) oscillatory motion
(iv) oscillatory motion
(v) circular motion.

Question 3.
Why can a pace or a foot step not be used as a standard unit of length?
Answer:
The pace or foot step has different lengths for different persons. So they cannot be used as a standard unit of length.

Question 4.
Arrange the following lengths in their increasing magnitude:
1 metre, 1 centimetre, 1 kilometre, 1 millimetre.
Answer:
1 millimetre > 1 centimetre > 1 metre > kilometre.

Question 5.
The height of a person is 1.65 m. Express it into cm and mm.
Answer:
(i) 165 centimetre
(ii) 1650 millimetre.

Question 6.
The distance between Radha’s home and her school is 3250 m. Express this distance into kilometre.
Answer:
3.250 kilometre.

Question 7.
While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm and at the other end is 33.1 cm. What is the length of needle?
Answer:
Length of needle = 33.1 cm
(-) 03.0 cm
= 30.1 m

Question 8.
Write the similarity and dissimilarity between the motion of a bicycle and a ceiling fan that has been switched on.
Answer:
The motion of a bicycle and a ceiling fan are in circular motion. Thus both show similar motion. But the ceiling fan moves without changing its position while the bicycle moves with changing its position with time. This shows dissimilarities between two motions.

Question 9.
Why could you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?
Answer:
We should not use elastic measuring tape to measure distance because the length of the measuring tape will increase when we pull or stretch the tape for measuring the length. The length may increase or decrease due to its elasticity. So we cannot measure the correct length by elastic measuring tape. The length measured by this tape either will be more or less depending on the elasticity of tape.

Question 10.
Give two examples of periodic motion.
Answer:
Examples of periodic motion:
(i) Motion of a pendulum.
(ii) Motion of a branch of a tree.
(iii) Motion of a child on a swing.

HBSE 6th Class Science Motion and Measurement of Distances Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Give one example where your estimate about the length of an object may be wrong.
Answer:
To measure the length of a table with stretched palm.

Question 2.
Give two examples of measurements that you make in your daily life.
Answer:
(i) To measure the length of cloth before sewing.
(ii) To measure the weight of vegetables before buying.

Question 3.
Name the S.I. unit of length.
Answer:
Metre (m).

Question 4.
Name the unit of length which should be used to express the thickness of a coin?
Answer:
Millimetre (mm).

Question 5.
What is measurement?
Answer:
The comparison of an unknown quantity with a standard known quantity is known as measurement.

Question 6.
Define unit.
Answer:
A quantity adopted as a standard of measurements of a physical quantity is called a unit.

Question 7.
What is a year?
Answer:
Time taken by the earth to revolve around the sun is called a year.

Question 8.
Name two devices used to measure length.
Answer:
(i) Metre scale
(ii) Screw gauge.

Question 9.
If you are sitting in a moving bus, you are at rest or in motion?
Answer:
We are in motion.

Question 10.
Is your class room at rest or in motion?
Answer:
The class room is at rest.

Question 11.
Is the hour is hand of a wall- clock at rest or in motion?
Answer:
Hour’s hand of the wall-dock is in motion.

Question 12.
What type of motion do the vehicles on a straight road perform?
Answer:
The vehicle motion is linear.

Question 13.
What type of motion do the wheels of a bicycle perform?
Answer:
Circular motion.

Question 14.
Give two examples of periodic motion.
Answer:
(i) Rotation of the earth on its axis.
(ii) Moon moves around the sun.

Question 15.
Give one example of an object changing their speed while in motion.
Answer:
Wind changes the speed of man while running with open umbrella.

Question 16.
Name two types of motion.
Answer:
(i) Circular motion
(ii) Oscillatory motion.

Question 17.
Give two examples of rectilinear motion.
Answer:
(i) A bullet fired from a rifle.
(ii) A boy sliding down a slope.

Question 18.
Give two examples of rotational motion.
Answer:
(i) The motion of blades of a ceiling fan.
(ii) Seconds hand in a clock.

Question 19.
What is motion?
Answer:
A body is said to be in motion when it changes its position with time.

Question 20.
Give two examples of linear motion.
Answer:
(i) Motion of bus in a straight line.
(ii) Motion of bullet.

Question 21.
Give an example of objects which move in a line.
Answer:
Falling of a ball freely.

Question 22.
Give an example of objects which move in a circle.
Answer:
Spinning wheel, blades of fan.

Question 23.
Give an example 9f objects which move to and fro.
Answer:
Pendulum of a wall clock.

Question 24.
Define translatory motion.
Answer:
Wheel of a car.

Question 25.
Give one example of rotatory motion.
Answer:
Spinning of a top, spinning wheel’s.

Short Answer Type Questions

Question 1.
State two precautions which you should take while using a metre-scale to measure the length of an object.
Answer:
(i) The scale should be placed along the length to measure. It should be very close to the objects to be measured.
(ii) Eye must be kept vertical above the end point of the object or point where the measurement is taken.

Question 2.
How do you measure the circumference of a one-rupee coin?
Answer:
To measure the circumference of coin wrap the thread around the coin. The length of the thread can be measured with the help of a metre scale.

Question 3.
Describe a method you would use to measure the thickness of a thin wire with the help of a metre scale.
Answer:
Wrap say 25 turns of thin wire around a pencil and see that the wrap should be very close to one another. The wire would form a coil. With the help of meter scale, measure the length of wire and divide it by total number of turns. It will be the thick-ness of a thin wire.

Question 4.
Write three rules which should be observed while writing symbols for S.I. units.
Answer:
Rules to be observed while writing S.I. units and their symbols:
(i) Symbols for units of quantities are to be written with a small letter. For example: symbol of Metre-m.
(ii) Symbol of unit named after a scientist is to be written in capital letters. Examples: Symbol for Kelvin-K.
(iii) Symbols for units are not to be followed by full stop. For example: Symbol for metre is m (and not m.)

Question 5.
Define circular motion.
Answer:
When the object moves along a circular track around a fixed axis. It is said to be in circular motion. Examples: Spinning top and spinning wheel.

Question 6.
Define oscillatory motion.
Answer:
A to and fro motion about its mean position is known as oscillatory motion.

Question 7.
Give some examples of oscillatory motion.
Answer:
Motion of a pendulum, motion of swing etc.

Question 8.
Give an example of objects for each of the following:
1. Object which moves in a line.
2. Object which moves in a circle.
3. Object which has a periodic motion.
Answer:
1. Light comes from the sun.
2. Movement of marry go around.
3. Motion of earth around the sun in one year.

Long Answer Type Questions

Question 1.
What is meant by a standard unit of measurement? Why is it necessary to have standard units of measurement? Name the SI unit of length. Write its symbol.
Answer:
Standard unit of measurement: A unit of measurement which has a fixed value which does not change from person to person or place to place, is called a standard unit of measurement.

It is necessary to have standard units of measurements for the sake of uniformity in measurements.
S.I. unit of length is metre. Its symbol of metre is m.

Question 2.
State the precautions which should be taken while using a metre scale to measure the length of an object (like a post card).
Answer:
Precautions to be taken while using a scale:
1. The scale should be placed parallel to the side of the object being measured. It should also be in a touch with the object being measured.
In Fig. 10.18(a) the scale is placed parallel to the side AB of the card which is to be measured. So, this is the correct placement of scale. This will give the correct reading for the length of card. From Fig. 10.18(a) we can see that the correct value of the length of card is 4.2 cm.

In Fig. 10.18(6), however, the scale is not exactly parallel to the side AB of the card being measured. So, it is a wrong placement of the scale. In this case the scale will give a wrong reading for the length of card (which will be greater than the actual length). For example, in Fig. 10.18(6), the scale shows a reading of 4.3 cm for the length of card, which is wrong.

2. While reading the scale, the eye must be placed vertically above the scale mark being read. If the eye is not vertically above the scale mark being read, then the reading becomes wrong.

In Fig. 10.19, the correct position of eye for reading the scale mark on the right side end of the card is at ‘A’ which is vertically above the scale mark being read. So, in Fig. 10.19, the correct reading of length of card from position A is 4.2 cm.

If we read the scale by keeping our eye somewhat towards left side at position B, then the scale reading appears to be 4.3 cm. And if the eye is kept at position C on the right side, then the scale reading appears to be 4.1 cm. The scale readings of 4.3 cm and 4.1 cm taken by keeping eye at positions B and C are wrong.

3. If the scale has a damaged zero mark or broken left end, measure the length of ah object starting from 1 cm mark of scale and then subtract 1 cm from the reading taken at the right end to get the actual length of object.

Question 3.
What is meant by: (a) circular motion and (b) rotational motion? Give two examples of circular motion and two examples of rotational motion.
Answer:
(a) Circular motion:
When an object moves along a circular path, it is called circular motion.
Examples:
(i) The movement of moon around the earth.
(ii) The move of earth around the sun:

(b) Rotational motion:
When an object turns (or spins) about a fixed axis, it is called rotational motion.
Examples:
(i) The motion of a spinning top.
(ii) The spinning of earth on its axis.

Question 4.
When an object is said to be in motion? Explain with the help of an example. State any four types of motion.
Answer:
An object is said to be in motion when its position changes with time. For example, when the position of a car changes with time, we say that car is moving or that the car is in motion. In Fig. 10.20, we see a car at position A in front of a house and tree at a particular urne. After 5 seconds we see the saine car at position B this quit far away from the house. This means that the position of this car is changing with time. So, we say that this car is in motion.
Four types of motion are:
(i) Rectilinear motion
(ii) Circular motion
(iii) Rotational motion and
(iv) Periodic motion.
(i) Rectilinear motion: Motion in a straight line is called rectilinear motion.
(ii) Circular motion: When an object moves along a circular path is called circular motion.
(iii) Rotational motion: When an object turns (or spins) about a fixed axis, it is called rotational motion.
(iv) Periodic motion: The motion which repeats itself after regular intetvals of time, is called periodic motion.

Question 5.
Give a method to measure the length of a pencil.
Answer:
To measure the length of a pencil, we choose a metre scale which should be placed along its length. In Fig. 10.21, zero mark on the scale coincides with the one end of the pencil and the reading coinciding with the other end of the pencil is taken. Since the ruler has some thickness, we may make an error if the eye is not correctly placed. The eye is to be placed exactly above the point where the measurement is to be taken as shown in Fig. 10.21 from the position A. The other end of the pencil coincides with 8.5 cm mark. The length of the pencil is 8.5 cm.

Motion and Measurement of Distances Class 6  HBSE Notes

• Different modes of transport are used to go from one place to another.
• In ancient times, people used length of a foot, the width of a finger and the distance of a step etc. as units of measurements. This caused confusion and a need to develop a uniform system of measurement arose.
• Now we use international system of unit (S.I. unit). This is accepted all over the world. 7.
• Metre is the unit of length in S.I, unit.
• Motion is the change in the position of an object. Motion may be rectilineal’, circular, rotational or
• periodic. gs
• Need of standard units: In ancient times, people used foot, arm, stretched palm as units of lengths. These methods were not satisfactory, because length of arm, foot and stretched palm vary from person to person. However if there are different units of length in the different parts of the world, it is very inconvenient for the exchange of scientific informations. Thus the need of standard units were felt. The unit which people agree to use as a basic unit for measurements, becomes a standard unit for that group of people for the sake of uniformity. Scientists all over the world have accepted following the standard unit for measuring length.
• The standard unit of length is metre. Its sub units are:
  10 mm = 1 cm, 100 cm = 1 metre,
  1000 m = 1 km, 3 x 10⁸ m = 1 light year.
• Measurements of length: In the S.I. system, the length is measured in unit metre (m). It is defined as the distance at 0°C between two lines drawn on a platinum irridium rod kept in the international bureau of weights and measure at screws near Paris. The following table shows the units of length and their relations to metre:

• Rules for measuring length correctly:
  → Fig. 10.1 shows the correct position of the scale:
  
  → To measure the length of the block. It is necessary to place the scale along the length you want to measure more than the actual length.
  → The eye must be placed directly above the points you are reading otherwise there will be an error due to parallex. The magnitude of the error is minimum when the scale is next to the point. The error increases as the distance of scale from the object increases.
  → While measuring the length of an object, if one end of that lies somewhere between few mm marks of the scale. If it is more than 1/2 mm, count it 1 mm or if less than 1/2, neglect it.
  → If the zero mark of the scale is damaged or edge of scale is not smooth, then start measuring from another mark. The difference between two marks gives its correct length.
  → To minimise the error due to wrong marking on the measuring scale, measure the length several times, using different parts of the measuring scale and take average to get nearest correct length.
• Measuring the length of a curved line: To measure the length of a curved line, we can use a thread or a divider from the geometry box.
  → Use a thread to measure the length of curved line AB (Fig. 11.4). Put a knot on the thread near one of its end and place this knot on point A. Now with the help of thumb and finger place a small portion of thread along the line. Now move the thumb which is towards the point A little further so that it takes the position of other thumbs next portion of the line. Repeat this process till last end point B is reached.
  → Now, stretched the thread along a metre scale and measure the length between the knot and the mark on the thread. This gives the length of the curved line.
• Motion is a state in which an object is steady or is at rest and the other object is moving. Motion may be rectilinear, circular, rotational or periodic.
• Periodic motion: Motion of a pendulum or motion of a branch of tree are examples of periodic motion. In such type of motion an object repeats its motion after a fixed interval of time.

Haryana State Board HBSE 6th Class Science Solutions Chapter 11 Light Shadows and Reflection Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 11 Light Shadows and Reflection

HBSE 6th Class Science Light Shadows and Reflection Textbook Questions and Answers

Exercises

Question 1.
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.

Answer:

Question 2.
Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:
Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, a flame of a gas burner, a sheet of card board, a lighted torch, a sheet of cellophone, a mix mesh, kerosene stone, sun, firefly, moon.
Answer:
(i) Opaque things: A piece of rock, a sheet of aluminum, a mirror, a wooden board, a wall, a sheet xrd board.
(ii) Transparent things: Air, water, a sheet of plane glass.
(iii) Translucent things: A sheet of polythene, a CD, smoke, fog, a sheet of carbon paper, a sheet of cellphone.
(iv) Luminous things: A piece of red hot iron, a lighted fluorescent tube, the flame of a gas burner, a lighted torch, sun, fixfly, moon.
(v) Non-luminous things: An umbrella, a wire mesh, kerosene stove.

Question 3.
Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?
Answer:
Yes, we can think of creating a shape that would give a circular shadow if held in one way and a rectmigular shadow if held in another way. If we held a round card board in front of source of light, it will create a round shadow on the ground and if we turn it at some other position, then it creats a rectangular shadow.

Question 4.
In a completely dark room, if you hold up a mirror in front of you, will you see a right-left inverted image of yourself in the mirror?
Answer:
In a completely dark room, we cannot see our right-left inverted image in the mirror, because there is no mrce of light and we only can see our image in the mirror, when light is reflected from the mirror.

HBSE 6th Class Science Light Shadows and Reflection Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Does the flame of a gas stove emit light?
Answer:
Yes, a gas stove flame emits light.

Question 2.
Give one example of a living thing which emits light.
Answer:
Firefly (Jugnu) is a living source of light.

Question 3.
Give the names of four different sources of light.
Answer:
Sources of light are: Sun, stars, firefly, electric bulb etc.

Question 4.
How does light travel from one point to the other?
Answer:
Light travels from one point to other in straight line.

Question 5.
What is the shape of the shadow?
Answer:
It is similar to the object which forms shadow.

Question 6.
How are shadows formed?
Answer:
Light coming from the source of light falling on the objects obstructed by the objects and does not go ahead. So a shadow is formed.

Question 7.
Are the edges of shadow sharp and distinct?
Answer:
Yes, the edges of the shadow are sharp and distinct.

Question 8.
Does the direction of shadow change during the day?
Answer:
Yes, the direction of shadow changes because the position of the sun changes during the day.

Question 9.
Does, the length of shadow change from season to season?
Answer:
Yes. The length of shadow changes from season to season.

Question 10.
What is a shadow?
Answer:
A dark patch formed behind an opaque object when it is placed in the path of light is called a shadow.

Question 11.
What is umbra?
Answer:
A region of total darkness is called umbra. No ray of light enters this region.

Question 12.
Define penumbra.
Answer:
A region of partial darkness which surrounds the umbra is called penumbra, some light rays reach this region.

Question 13.
What do we call a body that shines of its own?
Answer:
Luminous body.

Question 14.
Name one transparent and one opaque body.
Answer:
Trasparent air, glass, stone, wood (opaque).

Question 15.
What do we call a substance through which light can pass?
Answer:
Transparent substances.

Question 16.
Define opaque substance?
Answer:
The substance through which no light can pass.

Question 17.
Name two translucent substances.
Answer:
Glazed paper, oil paper.

Question 18.
Name two opaque substances.
Answer:
Ordinary paper, rubber sheet.

Question 19.
Name two cold sources of light.
Answer:
Firefly, tube light.

Question 20.
Define reflection of light.
Answer:
When a beam of light is incident on a smooth surface, apart of it os scattered back into the same medium, it is called reflection.

Short Answer Type Questions

Question 1.
Name any four artificial sources to scattering of fight. The air around the objects of light. allows this scattered fight to pass through it and
Answer:
1. Candle,
2. the oil jaino
3. tube
4. toren
5.electric bulb.

Question 2.
Why do objects in a room become transparent, translucent and opaque objects: visible even if sunlight does not enter it?
Answer:
The objects in a room become visible even if the sunlight dose not enter the room, due to scattering of light. The air around the objects allows this scattered light to pass through it and we can see the objects.

Question 3.
Classify the following into transparent, translucent and opaque objects: Wax, spectacle, a heap of salt, stone, dense smoke, wood, skin, balloon, rubber, membrane of tabla, blood, milk.
Answer:
Answer:
Transparent objects: Membrane of tabla, spectacles. Translucent objects: Dense smoke, blood, wax, balloon. Opaque objects: Stone, wood, rubber, milk

Question 4.
How will you convert a transparent glass sheet into a translucent sheet. Suggest any two ways.
Answer:
(i) By covering one side by butter paper.
(ii) By covering one side by thin sheet of plastics.

Question 5.
State the difference between umbra and penumbra.
Answer:

Question 6.
Define regular reflection.
Answer:
When a beam of light falls on a smooth and polished surface, then regular reflection takes place. The smooth surface gives a clear image due to regular reflection. Example: Reflection from a plane mirror.

Question 7.
State laws of reflection.
Answer:
Laws of reflection:
(i) The angle of incidents is equal to the angle of reflection.
(ii) The incident ray, reflected ray and the normal are in the same plane.

Question 8.
Name the features of the image formed by a plane mirror.
Answer:
(i) The image formed by a plane mirror is as far behind the mirror as the object is in front of it.
(ii) It is exactly the same size and shape.
(iii) Image is virtual.
(iv) It is erect but laterally inverted.

Question 9.
Give two effects of light on plants.
Answer:
(i) Plants use light energy to prepare their own food.
(ii) The tips or short apex of a photogenic plant moves towards it. Light acts as a stimulus to plants.

Question 10.
State two differences between transparent and translucent objects.
Answer:

Question 11.
Distinguish between regular and irregular reflection.
Answer:

Question 12.
What is lateral inversion?
Answer:
When we look in a plane mirror, we see the image of the objects placed in front of it. The left of the qbject becomes right of the image and the right of the objects becomes left of the image. This is called lateral inversion.

Question 13.
Why is firefly considered to be a cold source of light?
Answer:
The energy of some chemical reactions within the firefly is released not as heat but as light hence it is called a cold source of light.

Question 14.
Does the length of a shadow change during the day?
Answer:
Yes, the length of a shadow changes during a day. It is longer in the morning. After that it begins to decrease and it is shortest at 12.00 noon. Then begins to increase in length again.

Question 15.
Under what special circumstances, light does not travel in straight line?
Answer:
If the size of the object in the path of light is very small (0.0001 cm/less) light bends at the edge of the object. Thus in such case, light does not travel in straight line.

Question 16.
What would be the shape of an object so that it will cast no shadows on the ground in the light of sun?
Answer:
An object casts no shadow (or very little shadow) on the ground in sunlight when it is either transparent or it is at such a height from the earth that the umbra does not reach the surface of the earth. .

Question 17.
Why is your shadow longest at sunrise and shortest at noon?
Answer:
In the morning at the time of sunrise and in the evening at the time of sunset light rays falling on the earth are not straight. They are inclined. This is why our shadow at this time both (morning and evening) is the longest. At noon the sun is just over above our head and sun-rays fall vertically on the earth. Due to the vertical sun-rays, our shadow formed at noon is the shortest.

Question 18.
What does an object do when light falls on it?
Answer:
It may allow to pass the light through or it may completely cut the light from passing through by absorbing the light or it may scatter the light incident on it.

Question 19.
Why is silvered glass used as a mirror?
Answer:
The silvered glass has a smooth surface and the smoothness helps in forming clear image. Silvering makes it shiny and the shiny surface helps in reducing the absorption.

Long Answer Type Questions

Question 1.
Define the structure and working of a pin-hole camera.
Answer:
Pin-hole camera: It is a simple application of the rectilinear propagation of light.
Construction:
It consists of a rectangular card board box, such that its one side is made of ground glass screen, the side opposite to ground glass has a hole in the middle, whose size is equal to the pin-head of a common pin. The box is blackened from inside, so as to absorb any light falling on its walls.

Working:
(1) Consider a lighted candle AB, in front of pin-hole camera. The rays starting from points of candles, travel in all directions.
(2) A ray of light starting from point ‘A’ along with AH after passing through the pin-hole falls on ground glass screen at point ‘A’.
Similarly another ray starting from point ‘B’ along with BH after passing through the pin-hole will fall on ground glass screen at point ‘Bj
(3) A1B1 is the image of AB. The image formed here is turned upside down, because light travels in straight line.

Light Shadows and Reflection Class 6  HBSE Notes

• Light is an invisible energy which causes in us a sensation of vision. Though it cannot be seen, it unables us to see things.
• An object which emits light is called a source of light. Sources of light are natural as well as artificial. Sun is the main and brightest source of light. Stars, and jugnu (glow worm) and some fish also emit light.
• Artificial sources of light are man-made sources such as candles, lantern, gas lamps and electric bulbs. Bodies are visible only by ’ the light they send to our eyes. They may be luminous and non-luminous sources.
• Light travels in a straight line, which is called rectilinear propagation of light. It explains the formation of the image of an object in a pin-hole camera.
• When light falls on an object, three things can happen:
  → It is almost completely transmitted through the object.
  → Only one part of it may be transmitted and the rest is absorbed or spread out.
  → It may not be allow’ed to pass through at all. On this basis, we can classify the materials into three categories.
• Transparent materials, which allow light to pass through them and through which we can see clearly are known as transparent materials. Examples: Air, water, glass etc.
• Translucent materials: Substances through which light can pass partially and through which we cannot see clearly are called translucent materials. Examples: Wax paper, butter paper, greased paper etc.
• Opaque materials: Substances which do not allow light to pass through them are called opaque substances. We cannot see through them wood, stone etc.
• In the presence of light, opaque objects act as obstacles to propagate light and form in shadows behind them in the form of umbra and penumbra. The region of space where light from the source does not reach and hence the darkest region is called umbra.
• The region where the light does not reach from all parts of the source is called penumbra.
• When light falls on a smooth surface, they change their direction in a well defined manner, called regular reflection.
• There are two laws of reflection:
  → Angle ofincidence is equal to angle of reflection.
  → Incident ray, reflected ray and the normal all lie in the same plane.
• In a plane mirror, the reflected rays appears to come from some objects kept behind the mirror. This is called a virtual image. A real image can be obtained on a screen.
• Luminous objects. Objects which emit light their own are called luminous objects. Sun, stars, firefly, burning candle, electric bulb and gas lamps are examples of luminous objects. One lumin is the luminous flux of that source whose illuminating power is 1/4rc candela. The brightness is the property measured in units called foot candles. The modern unit now is lux. 1 Foot candle = 10.76 lux.
• Light travels in straight lines:
  → Take three pieces of a card board. Use supports to make them stand vertically on the table.
  → Make holes A, B, C in each of them such that the holes are in one straight line.
  → Now place a candle near hole A at the same height as the hole in the card board.
  → Now see from C. You will notice that the flame of the candle is visible. Now displace one of the card boards from its position so that the holes are no longer in a straight line. The flame is not visible.
  This activity shows that light from the candle travels in a straight line from the candle to the eyes.
• Formation of shadows: Shadows are formed when light is obstructed by objects. An opaque object casts a dark shadow, translucent casts a weak shadow and transparent objects cast no shadows.
  A shadow of the object is formed in the direction opposite to the side of the source of light. Take a wooden stick about half a metre long. Fix one end of it in open ground where there are no trees and buildings near it. Look its shadow in the morning and mark its points of shadow. Note the direction of sun with respect to the stick. It is formed opposite to the direction of sun.
  Again look at the shadow at about 11 a.m. and then about 2 p.m. At 11 a.m. the shadow formed is on the same side and about 2 p.m. shadow is formed in a direction opposite to that seen in the morning.
• Conclusion:
  → A shadow of an object is formed in the direction opposite to the side of the source of light.
  → Shadow moves according to the movement of sources of light or objects.
  → The length of shadow changes with time.
• Reflection of light: When a beam of light strikes on a plane surface a part of it is turned back into the same direction, it is called reflection.
• On a polished surface, regular reflection takes place and on rough surface irregular reflection takes place.
• Lateral inversion: When we look in a plane mirror, we see the image of the objects placed in front of it. The left of the objects become right and right of the objects become left of the image. Left hand side appears right handside in the image. This is called lateral inversion.

Haryana State Board HBSE 6th Class Science Solutions Chapter 16 Garbage In, Garbage Out Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 16 Garbage In, Garbage Out

Exercises

Question 1.
(a) Which kind of garbage is not converted into compost by the red-worms?
(b) Have you seen any other organisms, besides red worm, in your pit, if yes, try to find out their names. Draw pictures of these.
Answer:
(a) Garbage such as pieces of cloth, polythene bags, broken glass, aluminium wrappers, nails, old shoes and broken toys etc. not into compest by red warms.
(b) Yes, there are other organisms in a pit of compesting such as bacteria and some fungi which decompose the biodegradable wastes.

Question 2.
Discuss:
(a) Is garbage disposal the responsibility only of the government?
(b) Is it possible to reduce the problems relating to disposal of garbage?
Answer:
(a) No, the garbage disposal is our responsibility also. Because clear air, water and locality helps us to make healthy. So every citizen should care for waste disposal. We should not throw wastes carelessly. We should use less and reuse them and recycle the wastes. We should collect garbage carefully in dustbins and should save environment to pollute. It is our duty to keep our environment healthy and clean.

(b) Problems related to garbage disposed can be reduced easily, if we think carefully for disposal of wastes. We should collect, our kitchen or shop garbage in separate bags and dispose of in municipal dustbin. We should not throw any waste materials in the gali or on road. Everyone of us should use separate dust bins. Industry should use effluent plants for their waste disposal. Organic and agricultural wastes should be used for composting garbage should be properly discarded into landfill.
If we properly follow these action then disposal problem can be reduced.

Question 3.
(a) What do you do with the leftover food at home?
(b) If you and your friends are given the choice of eating in a plastic plate or a banana leaf platter at a party, which one would you prefer and why?
Answer:
(a) The left over food in our home is known as kitchen wastes. It comes in group—I category, which wastes are biodegradable by micro-organisms into useful products. Left over food at home is dumped into compost pits with other wastes such as rag, papers, and peels of vegetables which converted into manure after some days and used as food for plants.

(b) In a party I and my friend choose to eat in a banana leaf platter, due to the following reasons:
Banana leaf platter is an agricultural waste and it can be converted into compost after use. Compost is a manure, which is used by plants and crops for getting necessary nutrients. By using banana platter we also save our environment and surroundings to become pollute. Which is helpful for our health and healthy environment.

Question 4.
(a) Collect pieces of different kinds of paper. Find out which of these can be recycled?
(b) With the help of a lense look at the pieces of paper you collected for the above question. Do you see any difference in the materials of recycled paper and a new sheet ofpaper?
Answer:
(a) Pieces of newspapers, magezines, used envelops, note books, shiny plastic coated papers and shiny paper which are waxy in nature. From all these types of papers, plastic coated paper and shiny paper, could not be recycled. But paper pieces like newspapers, used envelops, notebooks, maga-zines, etc. cam be recycled and be converted into useful products, which are harmless for our society.

(b) When we see the recycled paper with the help of lense, we find that there is no great difference between them. The recycled paper quantity decrease upto some levels and there are roughness in recycled paper. This type of paper can be used for making carrybags and other packing materials.

Question 5.
(a) Collect different kinds of packaging materials. What was the purpose for which each one was used? Discuss in groups.
(b) Give an example in which packing could have been reduced?
(c) Write a story on how packing increases amount of garbage?
Answer:
(a) Collect different types of packaging materials such as, plastic cords, plastic bags, strips, jute bags and cords, clothes strips and any packaging materials from your locality and market shops. Discuss with your class mate in groups, in which each packaging materials used and write in your notebook.

(b) The shopkeepers should buy large amount of goods like nuts or coffee. By doing so they reduce the waste and packaging materials. They should buy goods in bulk and bigger quantities in a single box pakage. For exaple we can buy the large package of sugar, rice, cereals, tooth-pestes and detergents, etc. This type of shopping will reduce the wastages.

(c) Packing increases the amount of garbages. Every good or things are sold in small packets of plastic materials which are thrown out after use. This increases the garbage. Plastic bags, cans, aluminium foils and many other packaging materials are used and thrownout after use. These packaging materials increase garbage. Soft drinks, tooth-pastes and many other goods now-a-days are sold in plastic cans and aluminium cans.

Now-a-days every thing/goods such as ghee, refined, soaps, detergents, cereals and all eatable goods are sold in small packets. This increases the garbage upto a large extent. In this way we can say that packaging materials increases the amount of garbage.

Question 6.
Do you think it is better to use compost instead of chemical fertilizers? Why?
Answer:
We think that compost is better to use instead of chemical fertilisers because compost provides much nutrients to crop plants. It is easily absorbed by plant roots. Compost is cheaper than chemical fertilisers. It increases the fertility of the soil. On the other hand chemical fertilisers do not get decomposed by natural methods and they increase water and soil pollution. Chemical fertilizers are easily solunle in water. By leaching they reache the underground water and pollute water.
Therefore, we can say that compost is better use instead of chemical fertilisers.

HBSE 6th Class Science Garbage In Garbage Out Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Name any two garbage.
Answer:
Plastic bags and cans/tins.

Question 2.
Define garbage.
Answer:
Any materials which is discarded by us or which is of no use for us is called garbage.

Question 3.
What is landfill?
Answer:
A low lying open area in which garbage is thrown.

Question 4.
Are all garbage harmful to us?
Answer:
No, all garbage not harmful to us.

Question 5.
What type of garbage are used for composting?
Answer:
Garbage of our kitchen like fruits & vegetable peels, egg cells, waste food and tea leaves are used for composting.

Question 6.
Name some garbage which are not used as composting.
Answer:
Garbage, like, polythene bags, broken glass, aluminium wrappers and old shoes are not used for composting.

Question 7.
Define composting.
Answer:
The rotting and conversion of some materials into manure is called, ‘composting’.

Question 8.
Which type of dustbin is used for collecting garbage which is used again?
Answer:
Blue colour dustbin.

Question 9.
What type of garbage is collecting in green colour dustbin?
Answer:
Materials such as kitchen and other plant or animal wastes.

Question 10.
Should we bum the dried leaves?
Answer:
No, we should not bum the dried leaves.

Question 11.
Define ‘Vermicomposting’.
Answer:
The method of preparing compost with the help of redworms is called ‘Vermicomposting’.

Question 12.
What type of food red worm need?
Answer:
Red worms need food like, vegetable and fruits wastes, coffee and tea remains.

Question 13.
Which type of wastes is not used as red worm food?
Answer:
Wastes such as salt containing pickels, oil, vinegar, meat and milk should not be used as redworm food.

Question 14.
How redworms grind the food?
Answer:
Red worms do not have teeth for grinding food. They have a structure called gizzards for grinding their food.

Question 15.
What is the suitable season for the survival of red worms?
Answer:
They need normal temperature, not very hot nor very cold. They also need moisture around them.

Question 16.
What is ‘Papier mache’?
Answer:
It is a paste made of clay and paper and some rice husk.

Question 17.
Name few things we use that are made of plastics.
Answer:
Toys, shoes, bags, pens, combs and tooth brushes, etc. are few things that we use in daily life made of plastics.

Question 18.
How plastics are harmful for our health?
Answer:
Burning of plastics give out harmful gases, which may cause many health problems including cancer in humans.

Question 19.
How plastic bags are harmful for stray animals?
Answer:
Stray animals look for food in these bags, they end up swallowing these, sometimes they die due to this.

Question 20.
What are the problems we face. When plastic bags thrown away on roads?
Answer:
When we throw away plastic bags on roads or other places, they get into drain and sewer system. As a result drain get choked and water spills on the road.

Question 21.
Name one method by which we minimise garbage.
Answer:
We make a minimum use of plastic bags. We reuse the bags whenever it is possible to do so without any adverse affects.

Question 22.
What do you know about wastes?
Answer:
Wastes are the useless and unwanted materials discarded by humans.

Question 23.
Define domestic wastes.
Answer:
Domestic wastes include sewage, kitchen wastes, and garbage, etc.

Question 24.
What is incineration?
Answer:
The process of burning of wastes in a large furnace is called incineration.

Question 25.
Define vermieulture.
Answer:
The process of getting manure from biodegradable wastes by adding earthworms to the compost, is called vermieulture.

Short Answer Type Questions

Question 1.
How many types wastes can be divided?
Answer:
On the basis of physical, chemical and biological characteristic wastes can be divided into the following categories:
(a) Biodegradable wastes: Wastes which comprise of materials which has the ability to break down sofely and quickly by micro-organisms for example, dead and decaying remains of plants and animals, faecal remains water etc.

(b) Non-biodegadable wastes: Which do not breakdown into simple and harmless products by natural agents like bacteria and fungi are called non- biodegadable wastes. For example, metallic oxides, murcury, lead, DDT and radioactive wastes.

Question 2.
Define municipal wastes.
Answer:
Municipal wastes referred as garbage, etc. Municipal wastes is a combina-tion of wastes. They are papers, food wastes, plastics, metals, ash, glass, and others.

Question 3.
What are biodegradable wastes?
Answer:
Biodegradable wastes comprise of material which has the ability to break down safely and quickly by microorganisms. These originate from natural organic sources animals and plant based products.

Question 4.
Define the term domestic wastes.
Answer:
Human beings discard many things in our day to day life activities. They are considered as domestic wastes. Domestic wastes are:
(i) Sewage
(ii) kitchen wastes
(iii) garbage
(iv) others.
Human excreta and wastes from bathroom and kitchen come in category of sewage. Vegetables, fruits and other food wates are kitchen wastes whereas papers, rags, hairs, and house dust come in garbage category and plastic bags and rubber things are come in other categorties.

Question 5.
Burning of lianes are harmful to us. Explain.
Answer:
Garbage heaps of dried leaves are burnt most of the time. Farmers too often burn the husk dried leaves and part of crop plants in their fields. Burning of these, produces smoke and gases that are harmful to our health.

Question 6.
How earthworms are called farmers’ friends?
Answer:
Earthworms are farmers friends because they help to increase the fertility of the soil. They eat dust and make soil fertile. They are used to prepare vermicopot, which gives many nutrients to soil and ultimately to crop plants. So they are called farmers’ friend.

Question 7.
How do you prepare vermicompost?
Answer:
Vermicompost is prepared by the help of redworms. A pit of 30 cm deep is dug and a comfortable home is made for the redworms in it. Spray a thick layer of sand in it, stalk of plants’ husk or green leaves spread over the sand layer. Sprinkle some water to make this layer wet. Now put some redworms in this pit. Cover it with a sheet of cloth over the pit. Redworms eat fruits wastes’ coffee and tea remains. They grind their food. They eat equal to their weight. After 3/4 weaks soil like material is seen in the pit. This is vermicompost. Remove it from the pit and use after dried in sunlight.

Question 8.
Define recycling of paper.
Answer:
Collect old newspapers, magazines, used envelops, note-books and other papers and take a frame fitted with a net. Tear the paper into small pieces, put them in a tub and pour water over it. Let the paper remain submerged in water for a day. Make a thick paste of paper by pounding it.

Now spread the wet pastes on the wire mesh fixed to the frame. Put it gently to make the thickness of layer of paste as uniform as possible. Wait till waste drains off. Now remove the layer of paste from the frame, spread it on a sheet of newspaper by putting some weights so that these do not curl up. Thus recycled paper is prepared.

Question 9.
What is meant by the spoilage of landscape
Answer:
Spoilage of landscape is directly related to the improper waste management specially solid waste. The solid wastes may be slag heaps from mines, in paper mills, sugar mills, fertilizers and our household. They make our surrounding unhygenic. These spoils the landscape and destroy greenary of some areas. Soil becomes toxic in nature wastes accumulated places often becomes home of rats, house flies, mosquitoes and bacteria. These things destroy the beauty and usefulness of the place.

Question 10.
What are the health problems faced by the rag-pickers?
Answer:
Rag-pickers manually separate non- biodegradable wastes from the heap of garbage in the cities. These people are always exposed to biomedical wates like tape worms, liver flube eggs, sharp materials, broken glass, used syringes, needles etc. which can harm them to a great extent.

Some of the occupational hazards associated with these wastes handling are infectious of different types like skin and eye and respiratory, intestinal. Some diseases also result due to bites of animals. Exposer to dust and can result in cancer. Exposer to toxic agents is usually followed by its absorption and entry into the blood cancer.

Question 11.
List the various steps practiced in waste management.
Answer:
Various steps practiced in waste management are broadly divided into four steps:
(i) collection of wastes
(ii) segregation of waste
(iii) reduction and resource recovery
(iv) treatment and disposal.

Question 12.
How does a landfill basically works?
Answer:
The basic working of a landfill involves three steps:
(i) Deposit the refuse.
(ii) Compact it with buldozers.
(iii) Cover the garbage with at least 6 inches deep of soil after each day operation and with a final cover of 2 feet when the area is full.

Question 13.
What should be taken into consideration while selecting a landfills?
Answer:
While selecting a landfill the following points must be considered:
(i) Land requirements and its cost: The quantity of solid wastes, degree of compaction to be obtained, ratio of compacted wastes to the cover materials and depth of the fill determine the area of land and hence its cost.

(ii) Accessibility: The place where the disposal of wastes is to be done should be located either centrally or near the source generation. Also the landfill should be downward from the community.

(iii) Cover material: A sanitary landfill requires at least 15 cm cover of thick compacted soil at the end of each day work.

(iv) Climate: The frequency of rainfall, the velocity and direction of prevailing wind, and our all temperature time relationship are the factors to be considered for a particular site.

(v) Tropography: Any tropography may be used for the site of a landfill. However different site will pose special operational and design problems.

Question 14.
What are composting? What are its benefits?
Answer:
Composting is defined as the decomposition if heterogeneous matter in a mixed microbial population in the moist, warm and aerobic environment. The micro-organisms convert organic waste into humus which has a significant value for crops. The end product is called compost. It consists of nutrients and minerals like n, p, k and other trace elements.

Compost has the following benefits:
(i) It increases the fertility of the soil, rich in nutrients.
(ii) It also contains trace elements like copper, manganese and molybdenum etc. essential for growth of plants.
(iii) It improves the texture of the soil and increases the water absorption capacity of the soil.

Question 15.
Write short notes on:
(i) Incineration
(ii) Bio-methanation.
Answer:
(i) Incineration:
Incineration is the process of burning of wastes in a large furnance. It reduces the volume of waste by 20 to 30% of original volume and makes the products stable. It helps to eliminate any infectious organisms which may be present while reducing the volumes of wastes to be disposed of. If wastes is not segregated properly, incineration produces toxic ash and its leakage can pollute pond water.

(ii) Bio-methanation:
In this method organic matter like vegetable wastes, crop residues and animal excreta like cow-dung are decomposed in the absence of air and presence of water to produce biogas which is rich in methane. Biogas can be used to produce electricity, to cook to light streetlamps. It is pollution free method of dispoal of organic wastes in which leftover and slurry can be used as a manure.

Long Answer Type Questions

Question 1.
What can we do to minimise overuse of plastics and deal with garbage?
Answer:
(i) We make a minimum use of plastic bags. We re-use the bags wherever it is possible to do so without any adverse effects.
(ii) We insist shopkeepers use proper bags. We carry a cloth or jute bags when we go out for shopping.
(iii) We do not use plastic bags to store eatables.
(iv) We do not throw plastic bags here and there, after use.
(v) We never burn plastic bags and other plastic materials.
(vi) We do not put garbage in plastic bags and throw it away.
(vii) We use vermicompacting at home and dead with other kitchen wastes carefully.
(viii) We recycle papers.
(ix) We use both sides of paper to write. We use a slate for rough work. We use blank sheet of papers left in our note-books for roughworks.
(x) We make our family friends and others to follow proper practices for disposing different kinds of wastes.
The most important point to know and think about is that—more garbage we generate, more difficult it will be to get rid of it.

Question 2.
What we can do to manage waste?
Answer:
The following are some of the things we can do to manage waste:
(i) Throwing garbage in the correct bin.
(ii) Segregating household garbage into biodegradable and non-biodegradable.
(iii) Reducing the use of plastics.
(iv) Using materials that can be recycled.
(v) Buying things with least amount of packaging to avoid generation of waste.

Garbage In Garbage Out Class 6  HBSE Notes

• Landfill is an area where the garbage collected from a city or town is dumped.
• Converting plant and animal wastes including that from kitchen, into manure, is called composting.
• The method of making compost from kitchen garbage using red warms is called vermicomposting.
• Paper can be recycled to get useful products.
• Plastic cannot be converted into less harmful substances by the process of composting.
• We need to generate less wastes and find ways of dealing with the increasing amount of garbage in our surroundings.
• Wastes may be soiid wastes. Industrial wastes, Biomedical wastes, Agricultural wastes commercial wastes and radioactive wastes.
• Wastes are harmful but all are not for example soil is a waste when it is discarded from our homes.
• Proper disposal of wastes must, ensure that it does not pose a threat to people and the environment.
• Domestic wastes are sewage, kitchen wastes, Garbage and others.
• Sewage wastes can be divided into three categories: (i) Natural wastes (ii) Road traffic wastes and (iii) Behavioural wastes.
• Industrial wastes are from manufacturing industry, nuclear reactor, metallur-gical mining, textile, food processing, petroleum and other industries.
• Commercial wastes are generated in shops, restaurants, hotels, institutions, etc. A large quantities of plastic packing bottles, cans and clothings are discarded by these places.
• Commercial wastes may be of the following types: (i) Budding waste, (ii) Restaurants and shope waste, (iii) Wastes from printing.
• Bio-medical wastes generated by medical institutions and hospitals even day. It includes discarded cotton, bandages, plasters, syringes, medicines, saline bottles, hot water bags, and needles, tissues, bloods, fresh x- ray films etc.
• Agricultural wastes are farm animal waste fertilisers, pesticides, insecticides, fungicides, herbicides and rodenticides.
• Wastes may be biodegradable and non- biodegradable. It may be toxic and non-toxic.
• Bio-array use of some organisms to know the biological effects of a sustance or factor.

Haryana State Board HBSE 6th Class Science Solutions Chapter 15 Air Around Us Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 15 Air Around Us

Exercises

Question 1.
What is the composition of air?
Answer:
The major components of air are:
(i) Nitrogen (78%)
(ii) Oxygen (21%)
(iii) Noble gases (0.9%)
(iv) Carbon dioxide (00.3%)
(iv) Other gases, dust particles and water vapours (0.01%) by volume.

Question 2.
Which gas in the atmosphere is essential for respiration?
Answer:
Oxygen gas in the atmosphere is essential for respiration.

Question 3.
How will you prove that air supports burning?
Answer:
Take two plastic bottles and remove their base with the help of a sharp knife. Take two candles and coverthese two burning candles with the plastic bottles. After some time, candles stop burning and water level rises up in the plastic bottles.

Now make several holes in one plastic bottle and cover the lighting candle with this bottle. We see that candle burns continuously. This candle gets air from different holes and burns continuously till it is completely finished. This activity shows that air supports burning.

Question 4.
How will you show that air is dissolved in water?
Answer:
Take some water in a beaker and heat it slowly on a tripod stand with gas burner. We see that tiny bubbles are sticking on it. These
bubbles are mainly of oxygen gas present in air, i which is dissolved in water. When we heat water, the air dissolved in water escapes out in the form of bubbles.
This shows that air is dissolved in water.

Question 5.
Why does cotton lump get sunk T in water?
Answer:
Cotton lump contains air in it. There are various spaces in which air is filled. When cotton lump is put into water, air present in the vacant space dissolved in water and cotton lump sank.

Question 6.
The layer of air around the earth is known as
Answer:
The layer of air around the earth is known as atmosphere.

Question 7.
The component of air used by green plants to make their food is
Answer:
Carbon dioxide is needed by green 1 plants to make their food.

Question 8.
List five activities that are possible due to presence of air.
Answer:
Activities that are possible due to presence of air are as follows:
(i) Windmill.
(ii) Movements of sailing yachts.
(iii) Flying of aeroplanes, birds, etc.
(iv) Dispersal of seeds.
(v) Watercycle.

Question 9.
How do plants and animals help each other in the exchange of gases in the atmosphere?
Answer:
Plants and animals help each other in exchange of gases. They are interdependent on each other. All the animals require oxygen for their survival. It helps breaking down digested food in the body and release energy. This process is called respiration. During respiration, carbon dioxide gas is produced.

Plants consume this carbon dioxide gas for preparing their own food and release oxygen. They also use some oxygen for respiration. This oxygen gas is used for animals in their respiration process. In this way, plants and animals help each other in the exchange of gases in the atmosphere.

HBSE 6th Class Science Air around us Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Where do we get air?
Answer:
We get air from the atmosphere.

Question 2.
What is the use of air pressure?
Answer:
Air pressure is used in pumps.

Question 3.
The cover of air around the earth is called
Answer:
Atmosphere.

Question 4.
Air occupies and
Answer:
Space, mass.

Question 5
forms the earth atmosphere.
Answer:
Air.

Question 6.
What gases are found in the air?
Answer:
Air contains nitrogen, oxygen, carbon dioxide and inert gases and water vapours.

Question 7.
Which gas forms the largest part of the air?
Answer:
Nitrogen.

Question 8.
What part of the air is oxygen?
Answer:
Oxygen is l/5th part of the air.

Question 9.
What is the use of nitrogen in air?
Answer:
Nitrogen slows down the process of combustion.

Question 10.
State one biological importance of air dissolved in water.
Answer:
Dissolved air helps aquatic animals for breathing.

Question 11.
During photosynthesis, which gas is consumed?
Answer:
Carbon dioxide gas.

Question 12.
Which gas is released during photosynthesis?
Answer:
Oxygen gas.

Question 13.
Which gas is helpful for combustion?
Answer:
Oxygen gas.

Question 14.
When do plants release oxygen?
Answer:
Plants release oxygen during photosynthesis.

Question 15.
Name two variable components of air.
Answer:
(i) Nitrogen
(ii) Oyxgen.

Question 16.
Name two objects which are inflated by air.
Answer:
(i) Cycle tyre
(ii) Balloons.

Question 17.
Give the percentage composition of nitrogen and oxygen by volume in air.
Answer:
Nitrogen – 70% and oxygen – 21%.

Question 18.
Name two inert gases present in the air.
Answer:
(i) Argon
(ii) Neon.

Question 19.
Why do we need extra oxygen supply at high altitude?
Answer:
Because at high altitude air is thin.

Question 20.
Excepting oxygen and nitrogen, name two other gases present in the air.
Answer:
(i) Carbon dioxide
(ii) Argon.

Question 21.
Which component of the air is used in fire extinguishers?
Answer:
Carbon dioxide gas.

Question 22.
State one way in which air enters the air.
Answer:
Through respiration.

Question 23.
Why do we call neon and argon as inert gases?
Answer:
Because they do not react with any ; other element or compound in ordinary conditions.

Question 24.
Name two gases which can – damage historical monuments.
Answer:
(i) Nitrogen dioxide
(ii) Sulphur dioxide.

Question 25.
What is called wind?
Answer:
The moving air is called wind.

Question 26.
Name two properties of air.
Answer:
(i) Air occupies space
(ii) It has mass.

Question 27.
Write two importances of air in agriculture.
Answer:
(i) Air helps rotate wind-mill which is used to draw water from tube-wells.
(ii) Air helps in dispersion of seeds and ; pollen grains of flowers of several plants.

Question 28.
Give one important use of .! nitrogen.
Answer:
Nitrogen is used in the manufacture of fertilizers.

Question 29.
Name two major gases of air.
Answer:
Two major gases of air are:
(i) Nitrogen
(ii) Oxygen.

Short Answer Type Questions

Question 1.
Write the names of four main constituents of air.
Answer:
(i) Nitrogen
(ii) Oxygen
(iii) Carbon dioxide
(iv) Water vapours.

Question 2.
What are the uses of oxygen present in air?
Answer:
Uses of oxygen:
(i) Animals use oxygen for breathing and respiration.
(ii) Aquatic animals and plants use oxygen for breathing.
(iii) Mountaineers inhale oxygen at heights where air is thin.
(iv) Pure oxygen is used for artificial breathing in hospitals.
(v) Oxygen is used in oxy-acetylene torch for welding and cutting purposes.
(vi) Liquid oxygen is used as rocket fuels.

Question 3.
How can you show that air contains carbon dioxide?
Answer:
Take some lime water in a watch glass and keep it for a few hours in open air. A white crust is formed on the upper surface of the lime water. Lime water turns milky due to the presence of carbon dioxide in the air. This shows that air contains carbon dioxide.

Question 4.
Show that one-fifth volume of air is oxygen.
Answer:
Take a glass trough. Fill it about half with water. Add a few drops of ink to make the water coloured. Fix a candle on a solid iron rectangular block and place the block in water. Take a glass cylinder and mark it into five equal parts by passing a thin strip of paper at equal distance on its outer surface. Light the candle and invert the glass cylinder over it.

The flame of candle starts burning, then becomes and finally stops burning. Coloured water rises up in the glass cylinder and is filled one fifth with water. Thus one fifth of air is used in burning. Hence one fifth volume of air is oxygen.

Question 5.
How will you show that air contains water vapour?
Answer:
Put some ice blocks in a glass tumbler and keep it in the open air. Drops of water appear on the outer surface of glass tumbler after a few minutes. Air in contact with the tumbler gets cooled and the water vapour present in it condenses to give drops of water.

Thus we can see that water is present in air in the form of its vapours.

Question 6.
Explain why air is considered a mixture.
Answer:
Air is considered a mixture because:
(i) The composition of air varies from place to place and at depths and heights.
(ii) The constituents of air such as oxygen, nitrogen, carbon dioxide, water vapours etc. can be separated by simple physical methods.
(iii) The properties of air are the average of its constituents.
(iv) No energy is evolved or absorbed when various components of air (gases) are mixed to obtain air.

Question 7.
Mention five uses of air.
Answer:
Uses of air:
(i) Air is used by humans for respiration.
(ii) Air is necessary for burning.
(iii) Air is used for inflating the tyres of vehicles.
(iv) Balloons and balls can be used only when they are inflated with air.
(v) Compressed air is used in the break system for stopping trains.

Question 8.
How will you show that air is present in a lump of soil?
Answer:
Take a lump of dry soil in a beaker or glass tumbler. Adding water to it, we see that bubbles come out from the soil. This shows that soil contains air.

Question 9.
What will happen if the amount of oxygen in the air is increased?
Answer:
If the amount of oxygen in the air is increased, the burning of thing will not stop and fire will spread into large area which will be dangerous to humans and for the nature.

Question 10.
Why is nitrogen important for living organisms?
Answer:
Nitrogen in air is used for manufacturing food by the nitrogen fixation of atmospheric nitrogen into nitrates which mixes with the soil and plants absorb these as their food. So it is necessary and important for living organisms.

Question 11.
How can we see upto a long distance after it rains?
Answer:
When it rains, the dust in the atmosphere settles down to the ground. This is why we can see upto a long distance just after rain.

Question 12.
How do you know that solid particles are floating in air?
Answer:
Choose a sunny room in your home, now close all the doors and windows to make the room dark. Now open the window/door facing the sun just a little in such a way that it allows sunlight to enter the room only through a slit.

Now look the incoming sunlight slants carefully. We see some tiny shining particles moving rapidly in the slanting beam of sunlight. This shows that air contains dust particles.

Question 13.
Describe the process by which oxygen is naturally produced.
Answer:
Oxygen is naturally produced by the process of photosynthesis. Fill a beaker to about 3/4th with pond water and put a small plant in it. Cover it with a funnel. In this beaker now add a pinch of sodium bicarbonate.

Invert a test tube filled with water on the stem of funnel so that air bubbles get in the test tube.

Now put the apparatus in sunlight and observe after sometime. You will see that some gas has been collected in the test tube. Let half the test tube be collected with this gas. Now remove the test tube by putting thumb at the mouth of the test tube. Bring a splinter in the test tube. Splinters burn rapidly which show that it is oxygen gas.

Question 14.
What is liquid air? How can it be made?
Answer:
When air is cooled under reduced pressure, it is convert into liquid form. This air is called liquid air. Air is cooled under reduced air changes into liquid form.

Question 15.
What would happen if plants stop taking carbon dioxide?
Answer:
Plants prepare their own food with the help of carbon dioxide. They take carbon dioxide from the atmosphere and consume all the carbon dioxide released by animals through the process of respiration.

If plants stop taking carbon dioxide from the atmosphere, the amount of carbon dioxide increases in the atmosphere and the temperature of atmosphere will increase due to green house effect. Due to this, glacier will melt and there will be flooding on the earth. The nature living organisms will die.

Question 16.
Why do divers and mountaineers carry oxygen cylinders with them?
Answer:
Divers and mountaineers carry oxygen cylinders with them because at higher altitude and in oceans, the amount of air/oxygen is very thin. Therefore breathing becomes very difficult.

The divers and mountainears inhale oxygen from these cylinders so that they can breate easily. Therefore, they carry oxygen cylinders with them.

Long Answer Type Questions

Question 1.
Point out different uses of air.
Answer:
Uses of various constituents of air:
1. Uses of Nitrogen:
(i) It helps to slow down the process of combustion.
(ii) It dilutes the concentration of air.
(iii) On a very large scale nitrogen is used for the manufacturer of ammonia, which is used to make fertilizers and nitric acid.
(iv) Due to inertness nitrogen is used to produce a blanketing atmosphere during the processing of food to prevent oxidation which causes food to spoil and affects the natural taste.
(v) Nitrogen is used with argon for filling electric lamps.
(vi) Nitrogen is used for making explosive such as TNT and nitro cellulose.

2. Uses of Oxygen:
(i) Without oxygen, animal life is not possible. It is used for breathing and respiration.
(ii) Mountaineers inhale oxygen at heights, where oxygen is thin, from the cylinders they carry on their backs.
(iii) Fish and other aquatic animals use dissolved oxygen for breathing and respiration.
(iv) It is used in hospitals in many diseases for artificial respiration.
(v) Oxygen with acetylene is used as oxy- acetylene torch as welding and cuttings.
(vi) Liquid oxygen is used as rocket fuels.

3. Uses of Carbon dioxide:
(i) Carbon dioxide is used by plants for making their food.
(ii) Carbon dioxide is used in fire extinguishers.
(iii) It is used in soft drinks such as campa and limca.
(iv) Alcoholic beverages such as bear contains carbon dioxide.

4. Uses of Inert gases:
(i) Inert gas argon is filled in bulbs for the protection of filament of the bulb.
(ii) Helium is used to obtain low temperature.
(iii) Neon is used in special electric bulbs called neon-signs.
(iv) Radon gas is used in the treatment of cancer.

Instead of is used in inflating vehicle tyres, such as cars, scooters and motor-cycles. It is used in compressed form for digging, mining and breaking stones in machines. It is used in drying process for agricultural products such as grains, pulses etc. Air current makes the wind-mill to rotate. Wind-mill is used to draw water from the wells and tube-wells. Air is used for sailing gliders and aircrafts. It also helps in dispersal of seeds.

Air around us Class 6  HBSE Notes

• Air is found everywhere. When air is in motion, it is called wind.
• We cannot see air but we can feel it.
• Air occupies space. It is present in water and soil.
• Air is a mixture of oxygen, nitrogen, carbon dioxide, argon and few other gases, water vapours and dust particles.
• Oxygen is necessary for burning and breathing.
• The cover of air surrounding the earth is known as atmosphere.
• Atmosphere is essential for the life on the earth.
• Aquatic animals use dissolved oxygen/air in water for respiration.
• Plants use carbon dioxide to produce their food and release oxygen.
• The plants and animals are inter dependent for gaseous exchange.
• Air is useful in many ways. It is used for inflating tyres, balloons, and for winnowing.
• Air is also used in several musical instruments.
• Without oxygen, animal life is not possible. Mountaineers inhale oxygen at height, where air is thin from the cyclinders of oxygen.
• Oxygen is a supporter of combustion. Ice presence increases the burning process.
• Plants and animals exchange air and are interdependent on each other.

Haryana State Board HBSE 6th Class Science Solutions Chapter 14 Water Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 14 Water

Exercises

Question 1.
Fill up the blanks in the following:
(a) The process of changing of water into its vapour is called ……………. .
(b) The process of changing water vapour into water is called …………… .
(c) No rainfall for a year or more may lead to ………….. in that region.
(d) Excessive rain may cause …………. .
Answer:
(a) Evaporation
(b) Condensation
(c) Drought
(d) Flood.

Question 2.
State for each of the following whether it is due to evaporation or condensation.
(a) Water drops appear on the outer surface of a glass containing cold water.
(b) Steam rising from wet clothes while they are ironed.
(c) Fog appearing on a cold winter morning.
(d) Black board dries up after wiping it.
(e) Steam rising from a hot girdle when water is sprinkled on it.
Answer:
(a) Condensation
(b) Evaporation
(c) Condensation
(d) Evaporation
(e) Evaporation.

Question 3.
Which of the following statements are “true”?
(a) Water vapour is present in air only during the monsoon.
(b) Water evaporates into air from oceans, rivers, and lakes but not from the soil. water level would lower down. It will result into drought.
(c) The process of water changing into its vapours, is ailed evaporation.
(d) The evaporation of water takes place only in sunlight.
(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler.
Answer:
(c) True
(d) True
(e) True.

Question 4.
Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help? If yes, how?
Answer:
Yes, if we want to dry our school uniform quickly, we should spread our clothes near a anghiti or heater. Because near anghithi or heater, temperature is more, which helps water evaporation from the clothes and they dry quickly.

Question 5.
Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you notice a puddle of water around it. Why?
Answer:
When we keep a bottle of water taking out from refrigerator we notice some puddles of water around it. This is because the water-vapour near the surrounding atmosphere, condenses and deposites around the cooled water bottle. Water vapour always remains in the atmosphere.

Question 6.
To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses beomes wet?
Answer:
When we breathe on the spectacles, water vapours comes out from our breathe, and they condenses into water droplets when they come in contact of glass, because the glasses are cooler than the water vapours. So the glasses becomes wet, due to water puddles.

Question 7.
How does clouds formed?
Answer:
The water vapours that goes into air rises up along with air. As the air moves up, it gets cooler and cooler. At sufficient heights, air becomes so cool that the water vapour present in it condenses to form tiny drops of water called droplets. These droplets are very small, much smaller than even a grain of sand. These droplets are so small that lakhs of them together would form a drop of water.

These tiny droplets remain suspended in the air and moves along with it. When these water droplets in the air come closers they may combine to form slightly bigger droplets. In this way their sizes may become larger. Once the size of the droplets become larger than a definite size, they appear to us as clouds.

Question 8.
When does a drought occur?
Answer:
If it does not rain in a region for a year or more. The soil continues to lose water by evaporation and transpiration. Since it is not being brought back by rain, the soil becomes dry. The water level of water in ponds and wells of the region goes down and some of them may even dry up. The ground water may also become scarce. This may lead to drought.

HBSE 6th Class Science Water Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Define the term ‘cycle’.
Answer:
It is an event or phenomenon which repeats itself after sometime.

Question 2.
Name some activities in our daily life where we use water.
Answer:
We use water in our daily life in various activities such as: drinking, bathing and washing of clothes.

Question 3.
What is the main source of water?
Answer:
Oceans are the main source of water.

Question 4.
Define the term ‘evaporation’.
Answer:
The process of changing water from its liquid form to its vapour is known as evaporation.

Question 5.
Is evaporation a slow process or fast process?
Answer:
Evaporation is a slow process.

Question 6.
What is transpiration?
Answer:
Plants lost their excess water through their leaves into the air in the vapour form. This process is called transpiration.

Question 7.
Name two processes through which water vapour add conti-nuously into the air.
Answer:
The two processes are:
(i) Evaporation
(ii) Condensation.

Question 8.
Define condensation.
Answer:
The process of conversion of water vapours into liquid form of water is called ; condensation.

Question 9.
What is fog?
Answer:
The fog in winter is due to condensation of water vapour in air near the , surface of the earth.

Question 10.
What is precipitation?
Answer:
When water drops come together in the air becomes heavy and begin to fall, Falling of water drops is called precipitation.

Question 11.
How is snow or hails formed?
Answer:
When water droplets freeze in the air and begin to fall is called hails or snow.

Question 12.
Define water cycle.
Answer:
The water in its vapour form goes to air by evaporation and transpiration forms cloud and then comes back to the surface of the earth through the process of condensation and precipitation. This process is called water cycle.

Question 13.
Name three states of water.
Answer:
The three states of water are:
(i) liquid
(ii) solid
(iii) gaseous state.

Question 14.
What is the importance of convertibility of water from one state to another state?
Answer:
The easy convertibility of water from one state to another state makes its availability in all parts of the earth and throughout the year.

Question 15.
What is the percentage of water that is available for our use?
Answer:
Only a tiny fraction about 0.01% of total water is used by human beings.

Question 16.
What would happen if we do not water plants?
Answer:
Water is essential for plants for their food preparation. So the plants will die without water.

Question 17.
List two sources of water on the earth.
Answer:
(i) Underground water
(ii) surface water.

Question 18.
Where do we get water for our daily use?
Answer:
We get water from well, rivers and ponds.

Question 19.
During melting of ice, the temperature of the system changes/remains unchanged.
Answer:
Remains unchanged.

Question 20.
List the sources of water on the earth.
Answer:
Sources of water on the earth are: Rivers, ponds, lakes, well, spring and rain water.

Question 21.
Write the chemical formula of water.
Answer:
H₂O.

Question 22.
Name two sources of natural water.
Answer:
(i) River water
(ii) Lake water.

Question 23.
Name two solid forms of water.
Answer:
Snow, hails and frost.

Question 24.
Name universal solvent.
Answer:
Water is a universal solvent.

Question 25.
What is saline water?
Answer:
A sample of water contains more than 2% dissolved salts are called saline water.

Question 26.
Name the process by which saline water is made potable.
Answer:
Desalination process.

Question 27.
What do we use water for?
Answer:
We use water for drinking, bathing and cleaning purposes.

Question 28.
Give two uses of water in your home.
Answer:
(i) Cooking of food
(ii) Cleaning of utensils.

Question 29.
What is the use of water in agriculture?
Answer:
In agriculture, water is required to produce grains.

Question 30.
From where do we get fresh water supply?
Answer:
The ultimate source of fresh water supply is oceans.

Question 31.
Who supplies water to lakes and ponds?
Answer:
Oceans supply water to lakes and ponds.

Question 32.
What will happen if we do not water the plants in the pot?
Answer:
Water is essential for plants, for the preparation of their food. Without water, the plants will die.

Question 33.
List the sources of water for your daily use.
Answer:
We get water for daily use from wells, lakes, rivers, ponds and streams.

Question 34.
List the sources of water on the earth.
Answer:
Sources of water on the earth are: Rivers, lakes, ponds, well, spring, sea water, rain water and ocean water.

Question 35.
List the salts that can be obtained from the sea.
Answer:
Common salt, sodium bromide, magnesium chloride and potassium iodide.

Question 36.
Explain the term ‘salinity’.
Answer:
The rain water dissolves large amounts of salts, and it becomes salty. This is called salinity of water.

Question 37.
Write two uses of water in plants.
Answer:
(i) They use water in photosynthesis.
(ii) Water is essential for germination of seeds.

Question 38.
Name two sources of natural water.
Answer:
River water, lake water and stream water.

Question 39.
Name two solid states of water.
Answer:
(i) Snow
(ii) Ice
(iii) Frost.

Question 40.
What is saline water?
Answer:
A sample of natural water which contains more than 2% of dissolved salts, especially common salt is called saline water.

Short Answer Type Questions

Question 1.
How do fish and aquatic plants survive in water?
Answer:
Fish and aquatic plants needs oxygen to survive. Oxygen is slightly soluble in water. They get this dissolved oxygen for their survival.

Question 2.
How are clouds formed?
Answer:
Water vapours being lighter, rise up in the atmosphere. At the upper layer, they are condensed into tiny water droplets and form clouds. These clouds while falling down cause rains.

Question 3.
Give four physical properties of water.
Answer:
Physical properties of water:
1. It is a colourless liquid.
2. It freezes at 0°C and boils at 100°C.
3. Bad conductor of electricity.
4. It has a maximum density ofll cm3 at 4°C.

Question 4.
Define water cycle.
Answer:
Evaporation of water from oceans, ponds, rivers and lakes and from roads and streets to form cloud by condensation at higher altitude. When clouds rain, the rain water flows into the seas and oceans through rivers and streams. Some water percolates into the soil to form underground water. It comes again out in the form of spring and well. This is called water cycle.

Question 5.
Water is called a universal solvent. Give reasons.
Answer:
Water is called universal solvent because it dissolves any things in it. Many things dissolve in water as the time passes. So it is called universal solvent.

Question 6.
State different uses of water.
Answer:
Uses of water:
(i) We use water for drinking, bathing, cooking and cleaning of clothes.
(ii) Water is used in agriculture to produce food.
(iii) It is used in industries for carrying out various activities.
(iv) It is used for making electricity from flowing water.
(v) In thermal power stations, water is used to rotate generators through steam to produce electricity.
(vi) In railways, it is used to move railway engines. In factories, it is used in boilers to produce hot water and steam for running machines.

Question 7.
What are the different sources of water?
Answer:
Different sources of water are:
(i) Oceans
(ii) Seawater
(iii) Rivers
(iv) Lakes
(v) Streams
(vi) Well and dam water.

Question 8.
Write importance of water for sustaining life.
Answer:
Importance of water:
(i) Water is used by the organisms to transport soluble food materials to the cells.
(ii) It carries waste materials produced within the cells which are excreted out by the living beings.
(iii) It carries oxygenated red bloods to cells and tissues ofliving beings and brings back carbon dioxide produced during respiration and excreted out from the body.
(iv) Plants use enormous water during photosynthesis.
(v) It maintains body temperature.
(vi) Water is essential for germination of seeds.

Question 9.
How does rain water become saline?
Answer:
Water is a universal solvent, because it dissolves a large number of substances. When rain falls, it dissolves common salts and many other substances and minerals present on the earth. The rain water passes through different layers of earth, rocks, dissolves large amount of salt and other minerals. Thus it becomes salty.

Question 10.
How will you show the presence of water in air? .
Answer:
Take some pieces of ice in a beaker and keep it for sometime. After some time, we will observe that small water drops are formed on the cold outer surface wall of the beaker. These water drops are formed by the condensation of those water vapours which were present in air around beaker. This shows that water is present in air.

Question 11.
What are natural calamities?
Answer:
The conditions of floodings and drought ai’e called natural calamities.

Question 12.
What are the factors responsible for flooding?
Answer:
There are many factors for flooding like intensity and duration of rainfall, soil condition and presence of plants or trees on the grounds.

Question 13.
Give some uses of water in our houses.
Answer:
We use water in our houses for “many purposes; we need it for drinking, bathing, washing our clothes. We also use water for cooking, cleaning of utensils, watering of plants and other everyday activities.

Question 14.
How is water essential for plants?
Answer:
Water is essential for agriculture to produce grains; It is also required for growing plants that gives us fibres of cotton and jute. Water is required for the growth and in the process of photosynthesis for preparing their food. Germination of seeds requires water.

Question 15.
Who supplies water to rivers, lakes, ponds and wells?
Answer:
Oceans and seas are major sources of water on the earth. The water cycle fully depends upon oceans and seas. Rain is possible only due to water cycle and supplies water to rivers and ponds etc. Indirectly, ocean supplies water to these resources.

Question 16.
Define ground water.
Answer:
‘The ground water is actually rain water which mainly comes from seepage of water accumulated under the ground. Rain water percolates into the soil and reaches under the ground where water quantity increases and air decreases. This reserve water under the ground is called ground water.

Question 17.
We should use ground water judiciously. Why?
Answer:
If large quantity of ground water is taken out for various purposes, the water level goes down. Thus there will be shortage of water and it is not possible if we continuously use this water. So we should use ground water very carefully.

Question 18.
How are lakes and ponds formed?
Answer:
Lakes and ponds are small reservoirs of water. These are created by collection of rain water in low lying areas. Seepage from the ground water reserves also adds to the water in lakes and ponds.

Question 19.
What will happen if there is no rain at all?
Answer:
Rain is an important source of natural water. If there is no rain, the soil will lose its water by evaporation and become dry. Water will also be lost through transpiration process of plants. Rivers, ponds and wells will dry and the water level would lower down. All this will affect animals, humans and wild plants. If it continues for one or tw o years in continuation, it results into drought.

Long Answer Type Questions

Question 1.
What do you mean by water cycle in nature?
Answer:
Water constantly moves from the earth to the air and back again. The constant circulation of water is known as the water cycle.

The water in seas, rivers, lakes, ponds „r streams evaporates because of the heat of the sun. Plants also give out large amounts of water from their leaves. The water vapour rises up. The air higher’ up in the atmosphere is cooler. This cools the water vapour and it condenses to form tiny drops of water on dust particles. These drops of water together form clouds. As the clouds get cooled further, the water drops become bigger and heavier. When they become too heavy, they fall to the earth as rain.

The rain water enters the seas, rivers, lakes, ponds and streams and then evaporates again. Thus the water cycle in nature goes on.

Question 2.
How can we conserve the precious water?
Answer:
Water can be conserved by the following methods:
(i) We should use water very judiciously.
(ii) We should not waste water during its consumption.
(iii) We should not use drinking water in garden for watering plants.
(iv) We should not throw waste products into water resources.
(v) Water is used through pipes and spraying in agriculture.
(vi) Industrial wastes and effluents should not be released into rivers.
(vii) Ground water should be used when necessary. Leakage of taps should be stopped. In this way, we conserve water.

Water Class 6  HBSE Notes

• Water is essential for all living beings. Water is essential for sustaining life. Water vapour is always present in the air.
• Evaporation of water changes it from its liquid to gaseous state. Evaporation is a slow process.
• Evaporation of water is a continuous process that takes places at all places.
• Large amount of water evaporates into air from oceans, rivers, lakes, ponds and other water bodies and also from the soil.
• Plants release water vapours into air by the process of transpiration.
• The process of conversion of water vapour into liquid water is called condensation. Water vapours condense to form tiny droplets of water in the upper layers of air where it is cooler.
• Clouds appear in the sky when water droplets in air become larger than certain size.
• Falling of water drops from the clouds is called precipitation.
• The process of evaporation, transpiration, condensation, precipitation of water and its down hill flow to the oceans constitute the water cycle.
• Cycling of water between oceans and land ensures availability of water for all living organisms on the earth.
• Water exists in three states, that is solid, liquid and gaseous.
• Lakes, ground water and ice caps are some sources of water. Well water and spring water are examples of ground water.
• Water is a universal solvent, because it dissolves a large number of substances.
• Ocean water is highly saline. This water is harmful for agricultural purpose, animals and for human use.
• Pure water is colourless, odourless and tasteless liquid. Water becomes tasty due to dissolving of some gases such as C02 in it.
• Water dissolves oxygen gas due to which aquatic plants and animals respire. Presence of dissolved carbon dioxide is a source of food for aquatic plants.
• Water cycle helps in replenishing water sources and maintaining global weather.
• Evaporation of water from sea and other water bodies forms clouds at higher altitude. Clouds give rains and rain water flows back into the sea in the form of streams and rivers. Some rain water percolates through the soil to form underground water. This underground water comes up again and rushes out in the form of springs or is drained out as well water. This is called water cycle.
• There are two main natural sources of water: (i) Underground water, (ii) Surface water. Underground water is free from impurities.
• It is mainly of two types: (i) Well water, (ii) Spring water.
• Surface water is present on the surface of the earth. It is of three types: (i) rain water, (ii) river and lake water, (iii) sea water.
• Water is precious. It is one of the most wonderful gifts of nature.
• The total amount of water on the earth remains same but its distribution in different regions is different.
• We need water for various purposes, like drinking, bathing, washing our clothes, for cooking food, cleaning of utensils, watering of plants and other everyday activities.
• Water is required in agriculture to produce grains. It is also necessary for growing plants that gives us fibres and jute. Fibres are used for making clothes.
• Oceans and seas contain most of the water on the earth.
• Oceans and sea water is not fit for drinking and for agriculture purposes due to large amount of salt in it.
• Snow is another source of water. Snowmelts slowly and this water flpws down in the form of streafhs and rivers. Streams and rivers are another source of water.
• Most of the water which human beings use for drinking, washing and farming comes from rivers and streams.
• Water below the ground is known as underground water. This is mainly rain water that comes from seepage of water accumulated under the ground. The level below the ground where air is very less and only water is present is called water table.
• Lakes and ponds are small reservoirs of water. These are created by collection of rain water in low laying areas.
• Rain is a very important source of water for us. All resources of water are fed mainly by rains.
• If it does not rain for one or two years, soil will lose its water by evaporation and become dry. Rivers, ponds and lakes will dry and the
• The results of drought may be that no crops, food and fodder will decrease and humans and animals will die.
• In case of heavy rains, water level increases and flood occurs. Due to lack of air in soil due to heavy rains animals suh as earthworm, rats and snakes come out from the soil. Due to heavy rains, crops are also destroyed.
• Conditions of flood and drought are called natural calamties.
• Conservation of water is essential for sustaining life on the earth. Due to increasing population and increasing industrialisation and urbanisation, water requirements are also increasing.

Haryana State Board HBSE 6th Class Science Solutions Chapter 13 Fun with Magnets Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 13 Fun with Magnets

HBSE 6th Class Science Fun with Magnets Textbook Questions and Answers

Exercises

Question 1.
Fill in the blanks in the following:
(i) Artificial magnets are made in different shapes such as ………… and ………… .
(ii) The materials which are attracted towards magnet are called ………… .
(iii) ………… is not a magnetic material.
(iv) In olden days, sailors used to find direction suspending a piece of ………… .
(v) A magnet always has ………… poles.
Answer:
(i) bar magnet, horse-shoe magnet and round, shaped magnet
(ii) magnetic materials
(iii) leather
(iv) suspended magnet.

Question 2.
State whether the following statements are true or false:
(i) A cylindrical magnet has only one pole.
(ii) Artificial magnets were discovered in Greece.
(iii) Similar poles of a magnet repel each other.
(iv) Maximum iron filings stick in the middle of a bar magnets when it is brought near them.
(v) Bar magnets always point towards North-South direction.
(vi) A compass can be used to find East-West directions at any place.
(vii) Rubber is a magnetic material.
Answer:
(i) False
(ii) True
(iii) True
(iv) False
(v) True
(vi) False
(vii) False.

Question 3.
It was observed that a pencil sharpener gets attracted by both the poles of a magnet, although its body is made of plastic. Name a material that might have been used to make some part of it.
Answer:
A pencil sharpner is made up of iron metals-which is attracted towards the magnet. To some parts of it are made of iron/cobalt; which are magnetic materials.

Question 4. Column I show different positions in which one pole of a magnet is placed ner that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks:

Answer:

Question 5.
Write any two properties of a magnet.
Answer:
Properties of a magnet:
1. A magnet attracts magnetic materials such as iron, cobalt and nickel towards it.
2. When a magnet is suspended freely, it stands always in North-South direction.
3. Magnetic influence can pass through a screen of cloth, plastic and papers.

Question 6.
Where are poles of a bar magnet located?
Answer:
A freely suspended magnet always:omes to rest in one direction i.e., North-South direction.

The end pint of themagnet pointing towards north is called north pole and end pointing towards south is called south pole. Thus we an see that a magnet has two poles:
(i) North-pole
(ii) South-pole.
North and South poles are marked on the magnet.

Question 7.
A bar magnet has no markings to indicate its pole. How would you find out near which end is its north pole located?
Answer:
We take a bar m agnet and tied it with a thread in the middle. Now it is suspended freely tied the thread in a stand. We find that bar magnets stay in North-South directions.

The pole which is towards north is called north pole of the bar magnet. Thus we can find the poles of a magnet.

Question 8.
You are given an iron strip. How will you make it into a magnet?
Answer:
Method of making an iron strip , a magnet: Take the iron strip and place it on the table. Strike it with one pole of a bar magnet in one direction. When you reach the other end of the iron stick, leave the magnet and bring the same pole back to the starting end of the iron stick. Strike again in the same direction. Repeat this process about 30-40 times. Check whether the iron piece has now become a magnet. If not, continue the process for some more time. Remember that the pole and the direction of the magnet is not to be changed. In this way, an iron stick can be converted into a magnet. (See Fig. 13.3.)

Question 9.
How is a compass used to find directions?
Answer:
A compass is made on the property of a magnet, staying in north-south direction. This is a small glass case containing a magnetised needle pivoted on a nail. The needle can rotate freely. Whenever it is kept, its needle always rests in north-south direction, (See Fig. 13.4.)

Normally the north pole of the needle is painted red or some other indication is given to identify north and south poles. So using this needle, north and south can be identified.

Question 10.
A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Affect observed in each case is stated in column I. Possible reasons for the observed affects are mentioned in column II. Match the statements given in column I with those in column II.

Answer:
(A)-(d).
(B)—(c).
(C)—(b)
(D)—(a),
(E)—e).

HBSE 6th Class Science Fun with Magnets Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Name two places where magnets are used in your daily life.
Answer:
(1) Refrigerators
(2) Small pencil box.

Question 2.
Why do chess pieces stick to metallic card board?
Answer:
Because chess pieces are fitted with magnets.

Question 3.
What was the name of Greek shephered?
Answer:
His name was Magnes.

Question 4.
Magnetic ludo is not displaced with movement of vehicle. Why?
Answer:
Because the ludo is fitted with magnet.

Question 5.
From what materials magnets are made of?
Answer:
Magnets are made of from magnetic materials. .

Question 6.
Name two magnetic materials.
Answer:
(i) Iron
(ii) Cobalt.

Question 7.
Which, from the following objects, are attracted towards magnet?
Iron ball, plastic scale, wood stick, glass strip, pins.
Answer:
Iron ball and pins are attracted towards magnet.

Question 8.
What are non-magnetic materials?
Answer:
Materials which do not attract towards magnets are called non-magnetic materials.

Question 9.
Name some non-magnetic materials.
Answer:
Leather, plastic, cloth and paper etc.

Question 10.
What is a magnet?
Answer:
A magnet is an object which attracts pieces of iron, cobalt and nickel.

Question 11.
What happens when the north pole of a magnet ip brought near the north pole of a freely suspended magnet?
Answer:
They repel each other.

Question 12.
What happens when the north pole of a magnet is brought near the south pole of a freely suspended magnet?
Answer:
They attract each other

Question 18.
Can we have an isolated north pole or south pole?
Answer:
We cannot have an isolated north pole or south pole. They always exist in opposite direction.

Question 14.
Which iron is used for making a permanent magnet?
Answer:
Hard steel and alloys.

Question 15.
Which iron is used for making a temporary magnet?
Answer:
Soft iron.

Question 16.
Why are artificial magnets preferred to natural magnets?
Answer:
Artificial magnets are very strong in comparison with natural magnets.

Question 17.
In which direction does a freely suspended bar magnet come to rest?
Answer:
North-South direction.

Question 18.
Why does a magnetic needle get deflected when placed near a current carrying conductor?
Answer:
Due to magnetic field produced by current.

Question 19.
A bar magnet attracts iron fillings more strongly at two ends. What are these ends points called?
Answer:
These end points of the bar magnet are called its poles.

Question 20.
Name two devices where electromagnets are used?
Answer:
Electric bell and loud-speaker.

Question 21.
What type of magnet is used in an electric bell?
Answer:
U-shaped magnet is used in an electric bell.

Question 22.
What is the instrument in which directive property of a magnet is used?
Answer:
Mariner’s compass.

Question 23.
What is a temporary magnet?
Answer:
A magnet which retains its properties of magnet for a short time period is called temporary magnet.

Question 24.
How is a magnet demagnetised?
Answer:
(i) By heating
(ii) by hammering the magnet violently.

Question 25.
Two like poles of magnets are brought near each other. Will they attract or repel each other?
Answer:
They will repel each other.

Question 26.
What is a natural magnet?
Answer:
A natural magnet is a naturally occuring ore of iron which has attractive and directive property.

Question 27.
Can we have a magnet with a single pole?
Answer:
No, because unlike poles of equal strength exist together.

Question 28.
What is a sure test of magnetism?
Answer:
Repulsion is a sure test of magnetb.m.

Short Answer Type Questions

Question 1.
What is the difference between a temporary magnet and a permanent magnet?
Answer:

Question 2.
Give two applications of electromagnets.
Answer:
(i) They are used in cranes to lift heavy loads of scrap iron and iron sheets.
(ii) They are used to separate magnetic substances from non-magnetic substances.

Question 3.
What are the properties of a magnet?
Answer:
There are two main properties of a magnet:
(i) Attractive property.
(ii) Directive property.

Question 4.
Define attractive and directive property of a magnet.
Answer:
(i) Directive property: On suspanding a bar magnet freely with a thread we find that at rest it always points towards north- south direction.
(ii) Attractive property: Magnet has the property to attract iron, cobalt and nickel towards it. These substances are called magnetic substances.

Question 5.
How will you distinguish two identical bars of iron as a permanent magnet and an ordinary piece of iron?
Answer:
To identify the real magnet bring a third magnet near each end of the identical bars. In case of ordinary bar, both its end should be attracted towards magnet. But in case of a permanent magnet, one of its ends would be repelled.

Question 6.
What is the difference between the magnetic properties of soft iron and steel?
Answer:

Question 7.
Explain that induction precedes attraction.
Answer:
When iron piece is brought near a magnet, the iron is first temporarily magnetised by induction. Thus being two opposite poles, there is attraction. The iron piece first converts into a magnet having opposite poles, near its magnetised pole. Thus induction precedes attraction.

Question 8.
What is the difference between an electromagnet and a magnet?
Answer:
A magnet is a natural magnet with fixed magnetic effects. It is obtained from nature in the form of mineral. An electromagnet is a soft iron piece which shows magnetic effects only when eletric current is passed through it. Its magnetic effects can be increased or decreased by increasing electric current through conducting wire round the core.

Question 9.
What is a magnetic compass? What are its uses?
Answer:
A magnetic compass is a device which has a magnetic needle which is free to move on a pivot at the centre of a round box. It is used by sailors and navigators to find the directions. The compass needle is free to rotate and aligns in the north-south direction. Its free end that points north is marked red. (See Fig. 13.4.).

Long Answer Type Questions

Question 1.
What is a compass? Describe the construction of a compass with the help of a labelled sketch. How is a compass used to find directions?
Answer:
The compass is an instrument to find the directions of a place. The compass has a tiny magnet in the form of a needle which can rotate freely on a pivot (or pin). The pivoted magnetic needle of the compass is enclosed in a small brass box having a glass top. The compass has a circular dial with various directions marked on it. The needle of compass always conies to rest along the north-south directions. The north pole of compass needle is painted with different colour to distinguish it from the south pole.

In order to find the directions at a place, the compass is kept on a flat surface at that place. The needle of compass will soon come to rest along the north-south direction. The compass is then rotated until the painted end of needle is towards N (North) mark on the dial and the other end of needle is towards S (South) mark on the dial. We can now find any direction by looking at the dial of the compass.

Fun with Magnets Class 6  HBSE Notes

• Some materials such as magnetite show magnetic properties. These are called natural magnets.
• Magnet attracts some materials such as iron, cobalt, nickel. Such materials are called magnetic materials.
• The materials such as paper, cloth, leather etc. which are not attracted towards magnets are called non-magnetic materials.
• Magnetic attraction is maximum near the ends of the magnet. These ends are called magnetic poles.
• When suspended freely, a magnet always aligns in N—S direction.
• When suspended freely one pole of the magnet always points towards North. This is known as North pole.
• The other pole which points towrds South, is known as South pole.
• Opposite poles of two magnets attract each other whereas there is repulsion between similar poles.
• Magnetic influence can pass through screens of some substances like cloth, plastic, paper, glass etc.
• While travelling on the sea or air, a magnet can be used to find the directions. In olden days sailors used this property of magnet for finding directions when they were at sea.
• Compass is a small glass case, containing a magnetised pivoted on a nail. The needle can rotate freely.
• Wherever it is kept its needle always rests in North-South direction.
• On heating, or hammering magnetic property is destroyed.
• To keep it safe, store bar magnets in pairs with unlike poles together, separated by a bit of wood and two pieces of soft iron across the ends. For horse-shoe magnet, keep one iron piece across the poles.

Haryana State Board HBSE 6th Class Science Solutions Chapter 12 Electricity and Circuits Textbook Exercise Questions and Answers.

Haryana Board 6th Class Science Solutions Chapter 12 Electricity and Circuits

HBSE 6th Class Science Electricity and Circuits Textbook Questions and Answers

Exercises

Question 1.
Fill in the blanks:
(a) A device that is used to break an electric circuit is called ………… .
(b) An electric cell has …………. terminals.
Answer:
(a) switch
(b) two.

Question 2.
Make ‘true’ or ‘false’ for following statements:
(a) Electric current can flow through metals.
(b) Instead of metal wires, a jute string can be used to make a circuit.
(c) Electric current can pass through thermocol.
Answer:
(a) True
(b) False
(c) False.

Question 3.
Explain why the bulb not glow in the arrangement shown in Fig. 12.1.
Answer:
The bulb would not glow in the arrangement shown in figure because the one end of tester/screw driver is made up of plastic which does not allow the electric current of flow through it.

Question 4.
Complete the drawing in Fig 12.2. to indicate where the tree ends of the two wires should be joined to make the bulbs glow.

Question 5.
What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
Answer:
An electrical switch is used to open the circuit or to close the circuit due to which electrical gadgets start or stop. Electrical switch is used in many electrical gadgets such as: Television, Washing machine, Electrical mixy, Toaster, Heaters, Press, Tube-light, Electrical bulb, Torch, etc.

Question 6.
Would the bulb glow after completing the circuit shown in Fig. 12.13 if instead of safety pin we use an eraser?
Answer:
No, since eraser is an insulator so it does not allow the current to pass. Hence, the bulb will not glow.

Question 7.
Would the bulbs glow in the circuit in Fig. 12.5.

Answer:
No, the bulb will not light up. Because on one terminal, woolen thread is used instead of metal wires. Woollen thread is insulator in which no current flows. So the bulb will not light up.

Question 8.
Using your “conduction tester” on an object is was found that the bulb begins to glow is that a conductor or an insulator? Explain.
Answer:

The bulb lights up, when we use “conductor tester”, because the material we use is conductor. The material is made up of metals which are conductors of electricity. Therefore the bulb lights up. The circuit completes due to flow of electricity through metal materials. (See Fig. 12.6.)

Question 9.
Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Answer:
Our body is good conductor of electricity and rubber in insulator. During repairing work if the body comes in contact with current carrying wire then there will not be any accident as rubber does not allow the passage of current though it. Hence electrician uses rubber gloves while repairing an electric switch.

Question 10.
The handles of the tools like screwdrivers and pliers used by electricians for the repair work usually have plastic or rubber covers on them. Can you explain why?
Answer:
Plastic or rubber is an insulator which does not allow electric current to pass through it. The handles of the tools like screwdrivers and pliers used by electricians have covering of plastic or rubber, so that electric current may not pass through these tools to the body of the electrician to harm him.

HBSE 6th Class Science Electricity and Circuits Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Define electricity.
Answer:
Electricity is one of the most useful forms of energy.

Question 2.
Name two devices which work on electricity?
Answer:
(i) Toaster
(ii) Television.

Question 3.
From where is electricity supplied to our home?
Answer:
Electricity is supplied to our home from power station.

Question 4.
When electricity supply fails at night, from where do we get electricity?
Answer:
When electric supply fails at night, we get electricity from torch.

Question 5.
What supplies electricity to torch bulb?
Answer:
Electric cell supplies electricity to torch bulb.

Question 6.
What is an electric cell?
Answer:
It is a source of electricity.

Question 7.
Name two devices in which we use electric cell?
Answer:
(i) Alarm clock
(ii) Camera.

Question 8.
What type of terminals does an electric cell contain?
Answer:
Two types of terminals:
(i) Positive terminals (+) and (ii) Negative terminals (-).

Question 9.
Define battery.
Answer:
When two or more cells are joined together, we call it a battery.

Question 10.
How does an electric cell produce electricity?
Answer:
An electric cell produces electricity from chemicals stored inside it.

Question 11.
When does the electric bulb light up?
Answer:
Electric bulb lights up when the bulb and the connecting wire form a complete path which starts from one terminal of the electric cell and ends at the other terminal.

Question 12.
If there is any gap in the path, will the bulb light up?
Answer:
The bulb will not light up.

Question 13.
Define an electric circuit.
Answer:
The complete path from one terminal of the electric cell through the bulb and back to the other terminal of electric cell is called, a circuit.

Question 14.
In which direction does electric current flow in a circuit?
Answer:
Electric current flows in a circuit from positive terminal to negative terminal.

Question 15.
What is a fused bulb?
Answer:
When the filament is broken in a bulb, it is called the fused bulb.

Question 16.
What is an electric switch?
Answer:
A switch is a simple device that either breaks or completes the circuit.

Question 17.
Define an open circuit.
Answer:
When there is a gap between two terminals, it is called open circuit.

Question 18.
What is a closed circuit?
Answer:
A circuit where there is no gap between two terminals is called a closed circuit.

Question 19.
Define conductors.
Answer:
The materials through which electric current can flow are called conductors.

Question 20.
What are insulators?
Answer:
The materials through which the electric current cannot flow are called insulators.

Question 21.
Name two materials which are condutors.
Answer:
(i) Aluminium
(ii) Copper.

Question 22.
Name two insulators.
Answer:
(i) Rubber
(ii) Plastics.

Question 23.
Can we use rubber/jute instead of metal wires to connect circuit?
Answer:
No, we cannot use rubber/jute to connect circuit wires.

Question 24.
Name two metals which can be used to connect wires.
Answer:
(i) Copper
(ii) Aluminium.

Short Answer Type Questions

Question 1.
Classify the following into conductors and insulators:
Metal, Rubber, Plastic, Wood, Glass, Iron nail, Gold foil.
Answer:
(a) Conductors: Metals, iron nails, gold foil.
(b) Insulators: Rubber, plastic, wood, glass.

Question 2.
Why are copper and aluminium metals used for making wires?
Answer:
Copper and aluminium are metals. They are good conductors of electricity and electric current can flow through them. So they are used for making electric wires.

Question 3.
Name two insulators and two conductors.
Answer:
Insulators:
(i) Plastic
(ii) Rubber.

Conductors:
(i) Iron
(ii) Copper.

Question 4.
Name some devices in which electric cell is used.
Answer:
We use electric cell in many devices; such as alarm clock, wrist-watch, transistor, calculator, camera, lighter etc.

Question 5.
Define an electric cell.
Answer:
An electric cell contains a cylindrical pot covered by a thick paper sheet. Inside the a pot, there are some chemicals stored and a carbon rod in the middle covered by metal cap at its top. There are two terminals: (+) positive and (-) negative terminals in the cell. The (-) negative mark is negative terminal of the cell. Both terminals are on the same side. (See Fig. 12.7.)

Question 6.
Define a battery.
Answer:
When two or more electric cells are joined in such a way that positive terminal of one cell is joined by negative terminal of another cell, we call it a battery. (See Fig. 12.8.)

Question 7.
How does an electric cell produce electricity?
Answer:
Electricity is-produced by electric cell from chemicals stored inside it. When the chemicals of the cell are used up, it stops producing electricity.

Question 8.
What is an electric bulb? Explain.
Answer:
An electric bUlb contains tiny wire inside a glass cover, called filament. The filament is supported by two thick wires. One of the thick wires is connected to the metal case around the base of the bulb and other is connected to the metal tip of the base. The base and metal tip are two terminals of the bulb. The two terminals do not touch each other. (See Fig. 12.9.)

Question 9.
When does the bulb light up?
Answer:
The bulb light up only when the bulb and the wire complete, the path which starts at one terminal of the electric cell and ends at the other terminal. If there is any gap in the path, the bulb does not light up. It also does not light up if the path starts and returns to the same terminal of the electric cell. (See Fig. 12.10.)

Question 10.
Define an electric circuit.
Answer:
The complete path from one terminal of the electric cell through the bulb and back to the other terminal of the electric cell is called a circuit. As soon as the path from one terminal of the electric cell to the other terminal is complete, an electric current starts flowing through the circuit and the bulb starts glowing.

Question 11.
How does electric current flow in an electric cell?
Answer:
The electric current flows from the positive terminal of the electric cell to its negative terminal as shown in the figure below:
In the bulb, the current enters through one of its terminals, flows through the filament inside the bulb and comes out through the other terminal of the bulb. The bulb lights up.

Question 12.
What is a fused bulb?
Answer:
If the filament is broken, the circuit is not complete and hence the current cannot flow. The bulb with broken filament is called a fused bulb.

Long Answer Type Questions

Question 1.
Draw a labelled sketch of a torch. Give its various parts and working.
Answer:
Parts of a torch:
(a) A metallic or plastic casing
(b) Torch bulb
(c) Glass reflector
(d) Metal switch contacts
(e), Slide switch
(f) Two or three dry dells according to size of the cell
(g) Metal spring attached to slide switch
(h) Lamp contact.

Working of torch:
Electric current flows in the closed circuit. When slide switch is slided forward, cell contact is complete with the bulb, circuit is now closed. Electric current starts from one terminal of the electric cell and comes back to the other terminal of the electric cell. Bulb glows and starts emitting light.

Question 2.
Describe an electric bulb.
Answer:
It consists of a tiny coiled wire, supported by two thick wires making a V-shape. This tiny coiled wire is called filament. The’ two thick wires making this v-shape are called supporting wires. The lower end of one of these wires is connected to the metal casing at the side of the bulb. The lower end of the second wire is connected to the metal top at the base and the metal casting at its lower end act as terminals of the bulb. The space in between the terminals of the bulb is filled with sealing wax. This prevents the terminals from making contact with one another.

Where the electric current passes through the filament of the bulb through the terminals, it gets white hot and produce light

(a) Torch bulb
(b) Inside a torch bulb

Question 3.
What is electric circuit? How many types of electric circuit are there? Define them. Draw a diagram to show the closed Circuit for switch, bulb and dry cell.
Answer:
Electric circuit:
The complete path of flow of electricity from one terminal of the cell to its other terminal through various electrical components is called an electric circuit.

There are two types of electric circuit: (a) Open electric circuit, (b) Closed electric circuit.

(a) Open electric circuit:
The circuit in which electrical contact at any point is broken is called open electric circuit.

(b) Closed electric circuit:
The circuit in which electric current flows from one terminal of a cell or battery to the other is called a closed circuit.

Question 4.
Does supply of electricity have two-way path?
Answer:
Yes . There are always two wires coming from the electric power house. One of the wires brings the current and is called live wire. The current coming through live wire passes through an electric appliance (such as a bulb, fan, etc.) and then flows out through another wire to power house. The wire which carries away the current to power house is called neutral wire.

These days there is a third wire, which is commonly called earth wire. This wire is attached to the metallic bodies of the electric appliances. It is a kind of safety wire which protects us from electric shocks and electric fires.

Electricity and Circuits Class 6  HBSE Notes

• Electricity is the most useful forms of energy. We use many devices which work on electricity such as heater, washing machine, T.V., tube-light, etc.
• Electric cell is a source of electricity. It has two terminals: (i) Positive terminal and negative terminal.
• Electric cell produces electricity from the chemicals stored inside it.
• A bulb has two terminals. The complete path from one terminal of the electric cell through the bulb and back to the other terminal of electric cell is called a circuit.
• When there is a complete circuit from one terminal of the electric cell to the other, electric current flows through the circuit.
• The electric current flows from the positive terminal of the electric cell to its negative terminal.
• Switch is a simple device that either breaks the circuit or completes it to stop or start the flow of current.
• Materials through which the electric current can flow are called conductors;
• Materials through which the electric current cannot flow are called insulators.
• Electric cells are used in many devices such as an alarm clock, wrist-watch, transistor and camera etc.
• When two electric cells are jointed together, we call it a battery.
• In an electric bulb there is a thin wire, called filament and two thick wires.
• Electric circuit: The complete path from one terminal of the electric cell through the bulb and back to other terminal of electric cell, is called a circuit.
• Electric switch: A switch is a simple device that either breaks the circuit or completes it.
• Conductors and insulators are equally important for us.
• Our body is a good conductor of electricity. Therefore be careful when you handle an electrical appliance.