Class 7

Haryana State Board HBSE 7th Class Science Solutions Chapter 15 Light Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 15 Light

HBSE 7th Class Science Light Textbook Questions and Answers

Question 1.
Fill in the blanks :
(a) An image that cannot be obtained on a screen is called _________.
(b) Image formed by a convex _________ is always virtual and smaller in size.
(c) An image formed by a _________ mirror is always of the same size as that of the object.
(d) An image which can be obtained on a screen is called a _________ image.
(e) An image formed by a concave _________ cannot be obtained on a screen.
Answer:
(a) virtual image
(b) mirror
(c) plane
(d) real
(e) lens.

Question 2.
Mark ‘T’ if the statement is true and ‘F’ if it is false :
(a) We can obtain an enlarged and erect image by a convex mirror.
(b) A concave lens always form a virtual image.
(c) We can obtain a real, enlarged and inverted image by a concave mirror.
(d) A real image cannot be obtained on a screen.
(e) A concave mirror always form a real image.
Answer:
(a) F
(b) T
(c) T
(d) F
(e) F

Question 3.
Match the items given in Column I with one Or more items of Column II.

Answer:
(a) (v)
(b) (ii)
(c) (i)
(d) (iii)
(e) (vi)

Question 4.
State the characteristics of the image formed by a plane mirror.
Answer:

• Plane mirror forms an erect image.
• It forms a virtual image.
• Size of the image is same as that of the object.
• Image gets formed at the same distance behind the mirror as the object stands infornt of it.
• Image formed is a laterally inverted image, i.e. right hand side of the object seems to be the left hand side and vice-versa.

Question 5.
Find out the letters of English alphabet or any other language known to you in which the image formed in a place mirror appears exactly like the letter itself. Discuss your findings.
Answer:
Letters like A, H, I, M, O, T, U, V, W etc appear same when seen through a plane mirror.

Question 6.
What is a virtual image? Give one situation where a virtual image is formed.
Answer:
The image which cannot be taken on a screen is called a virtual image. When some object is placed very close to the concave mirror we do not get any image of that object on the white screen placed behind the mirror. Such image is called a virtual image.

Question 7.
State two differences between a convex and a concave lens.
Answer:

Question 8.
Give one use each of a concave and a convex mirror.
Answer:

• Use of Concave mirror: Concave mirror is used by dentists to- examine the teeth.
• Use of Convex mirror: Convex mirror is used as side view mirror in vehicles.

Question 9.
Which type of mirror can form a real image?
Answer:
Concave mirror can form a real image.

Question 10.
Which type of lens forms always a virtual image?
Answer:
Convex lens always form a virtual image.

Choose the correct option in questions 11-13

Question 11.
A virtual image larger than the object can be produced by a _________.
(i) concave lens
(ii) concave mirror
(iii) convex mirror
(iv) plane mirror
Answer:
(iii) convex mirror

Question 12.
David is observing his image in a plane mirror. The distance between the mirror and his image is 4 m. If he moves 1 m towards the mirror, then the distance between David and his image will be _________.
(i) 3 m
(ii) 5 m
(iii) 6 m
(iv) 8 m
Answer:
(i) 3 m

Question 13.
The rear view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be _________.
(i) 1m/s
(ii) 2m/s
(iii) 4mls
(iv) 8m/s
Answer:
(iii) 4mls

Extended Learning-Activities and Projects

Question 1.
Play with a mirror Write your name with a sketch pen on a thin sheet of paper, polythene or glass.

Read your name on the sheet while standing in front of a plane mirror. Now look at your image in the mirror.
Answer:
Do it yourself.

Question 2.
A burning candle in water
Take a shoe box, open on one side. Place a small lighted candle in it. Place a clear glass sheet (roughly 25 cm x 25 cm) infront of this candle (fig. 15.1). Try to locate the image of the candle behind the glass sheet. Place a glass of water as its position. Ask your friends to look at the image of the candle through the sheet of glass. Ensure that candle is not visible to your friends. Your friends will be surprised to see the candle burning in water. Try to explain the reason.
Answer:
Do it yourself.

Question 3.
Make a rainbow’.
Try to make your own rainbow. You can try this project in the morning of in the evening. Stand with your back towards the sun. Take a hosepipe or a water pipe used in the garden. Make a find spray in front of you. Your can see different colours of rainbow in the spray.
Answer:
Do it yourself.

Question 4.
Visit a laughing gallery in some science centre or a science park or a village mela. You will find some large mirrors there. You can see your distorted and funny images in these mirrors. Try to find out the kind of mirrors used there.
Answer:
Do it yourself.

Question 5.
Visit a nearby hospital. You can also visit the clinic of an ENT specialist, or a dentist. Request the doctor to show you the mirrors used for examining ear, nose,
throat and teeth. Can you recognise the kind of mirror used in these instruments?
Answer:
Do it yourseld.

Question 6.
Role play
Here is a game that a group of children can play. One child will be chosen to act as object and another will act as the image of the object. The object and the image will sit opposite to each other. The object will make movements, such as raising a hand, touching an ear, etc. The image will have to make the correct movement following the movement of the object. The rest of the group will watch the movements of the image. If the image fails to make the correct movement, she/he will be retired. Another child will take her/his place and the game will continue. A scoring scheme can be introduced. The group that scores the maximum will be declared the winner.
Answer:
Do it yourself.

HBSE 7th Class Science Light Important Questions and Answers

Very Short Answer Type Questions

Question 1.
What do you mean by rectilinear propagation of light?
Answer:
Rectilinear propagation of light means that beam of a light always travels in a straight line.

Question 2.
How can we change the direction of the light?
Answer:
We can change the direction of the light by the phenomenon called reflection.

Question 3.
What do you mean by reflection of light?
Answer:
When a ray of light falls on the surface of any mirror, it bounces back in the same medium. This is called reflection of light.

Question 4.
What is a mirror?
Answer:
Any polished or shining surface is called a mirror.

Question 5.
What do you mean by a real image?
Answer:
Image which can be obtained on a screen is called a real image.

Question 6.
What do you mean by a virtual image?
Answer:
Image which cannot be obtained on a screen is called a virtual image.

Question 7.
What is a convex mirror?
Answer:
A mirror which reflects the light from its inner polished side.

Question 8.
What is a concave mirror?
Answer:
A mirror, which reflects light from its outer polished surface.

Question 9.
What kind of image is formed by a plane mirror?
Answer:
It forms an erect, virtual and image of same size as that of the object.

Question 10.
What kind of image is formed by a concave mirror?
Answer:
It can form both real and virtual, erect or inverted image.

Question 11.
What kind of image is formed when an object is placed very close to the concave mirror?
Answer:
A virtual erect and a magnified image will be formed.

Question 12.
What kind of image is formed by a convex mirror?
Answer:
Convex mirror forms an erect, virtual and diminished image.

Question 13.
What kind of image is formed by a concave lens?
Answer:
An erect, virtual and diminished image is formed by a concave lens.

Question 14.
What happens when a beam of light enters a prism?
Answer:
The beam of light splits into seven colours.

Question 15.
What do you mean by lateral inversion?
Answer:
When right hand side of an object appears as the left hand side and vice-versa.

Short Answer Type Questions

Question 1.
What is a virtual image? Give one example of virtual image.
Answer:
Virtual image : It is an image which cannot be obtained on a screen. It is formed when the reflected rays appears to meet each other but actually do not meet in reality. It is always erect. Image formed by a plane mirror is a virtual image.

Question 2.
What is real image of an object?
Answer:
Real image is formed when two or more reflected rays actually meet. This image can be obtained on a screen. It is always inverted. Pin-hole camera forms a real image.

Question 3.
Give two uses of concave mirror.
Answer:

• It is used as a reflector in search-light and head-lights of the automobiles.
• It is used as a shaving mirror.

Question 4.
Give two uses of convex mirror.
Answer:

• It is used in the cars and scooters to get the rear view to see the traffic coming from behind.
• It is used as reflectors in street lamps so as to diverse the light over a large area.

Question 5.
What do you mean by reflection of light?
Answer:
When a beam of light is incident on a plane surface a part of it is scattered back into the same medium. The scattering back of light into the same medium is called reflection.

Question 6.
Why is silvered glass used as a mirror?
Answer:
The silvered glass has a smooth surface and the smoothness helps in forming a clear image. Silvering makes it shiny and the shiny surface helps in reducing the absorption.

Question 7.
A man walks towards a plane mirror. At what rate will his image move if :
(a) the mirror is stationary,
(b) the mirror moves towards the man.
Answer:
(a) If the mirror is stationary the image moves at the same rate as the man.
(b) When the mirror moves towards the man the image moves at twice the rate of the mirror.

Question 8.
State four characteristics of the image formed by a plane mirror.
Answer:

• The image formed is as far behind the mirror as the object.
• It is exactly of same shape and size.
• It is erect but laterally inverted.
• It is virtual.

Question 9.
Distinguish between a real image and a virtual image.
Answer:
Difference between a real and virtual image :

Question 10.
Distinguish between a concave mirror and convex mirror.
Answer:

Long Answer Type Questions

Question 1.
How would you ascertain that a given mirror is a (a) Plane mirror, (b) Concave mirror, (c) Convex mirror without touching their surface?
Answer:
Hold the given mirror in the hand near your face, see the image. If the image is upright of the same size and does not change in size by moving the mirror, then the mirror is a plane mirror.

It the image is upright, larger and becomes inverted on moving the mirror away from your face, then the given mirror is a concave mirror. If the image is upright, smaller than your face and remains upright on moving the mirror away from your face, then the given mirror is the convex mirror. In this way one can ascertain the kind of mirror, without touching its surface.

Light Class 7 HBSE Notes

1. Light is an invisible energy which casue the sensation of sight.

2. Any object that gives out light is called the source of light e.g. Sun, firefly, candle etc.

3. Sun, moon, stars etc are called natural sources of light.

4. Candle, bulb etc are called man-made sources of light.

5. Light always travels in a straight line, this property of light is called the rectilinear propagation of light.

6. When light falls on a plane mirror, it falls back. This property of turning back of light is called in the same medium is called reflection of light.

7. There are two laws of reflection :
(i) The incident ray the normal at the point of incidence and the reflected ray lie in the same plane.
(ii) The angle of reflection is equal to the angle of incidence.

8. Any polished and shining surface is called a mirror.

9. Mirrors are of two types : concave mirror and convex mirror.

10. Concave mirror form a real and inverted image of the object.

11. Convex mirror always forms a virtual erect and small image.

12. Real image is one which can be obtained on a screen.

13. Virtual image is one, which cannot be obtained on a screen.

14. Lenses are also used to form images. Lenses are used to make spectacles, microscopes, magnifying glasses and telescopes etc.

15. Lenses are of two types. Concave lens and convex lens.

16. Concave lens is also called diverging lens, because it diverge the light falling on it. Convex lens is called the converging lens because it converges the light falling on it.

17. Concave lens forms, virtual erect and diminished image.

18. Convex lens can form both real and virtual images depending upon the position of the object. It magnifies the objects, when they are placed very near the lens.

19. White light splits into seven colours when it enters a prism.

20. This phenomenon is called dispersion of light.

Haryana State Board HBSE 7th Class Science Solutions Chapter 16 Water: A Precious Resource Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 16 Water: A Precious Resource

HBSE 7th Class Science Water: A Precious Resource Textbook Questions and Answers

Question 1.
Mark ‘T” if the statement is true and ‘F’ if it is false:
(a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T/F)
(b) Water shortage is a problem faced only by people living in rural areas. (T/F)
(c) Water from rivers is the only source for irrigation in the fields. (T/F)
(d) Rain is the ultimate source of water. (T/F)
Answer:
(a) T, (b) F, (c) F, (d) T.

Question 2.
Explain How gropndwater is recharged?
Answer:
The ground water get recharged through the process of infiltration. Infiltration means seeping in water from rivers and lakes into the empty spaces and crack deep below the ground.

Question 3.
There are ten tubewells in a lane of fifty houses. What could be the long term impact on the water table?
Answer:
The effect on the water table depends on the replenishment of the underground water. As only five families will share a tubewell, the water used for daily domestic purpose will not effect the water table as such. But if there is acute shortage of rains the water used by the families will not replenished and water table will fall down.

Question 4.
You have been asked to maintain a garden. How will you minimise the use of water?
Answer:
The water is used to water the plants in a garden. To minimise the wastage of water we will use the technique of drip irrigation, which directly throws water at the base of plants. I will Check the leakages in the water papers. I will arrange small pits for rain water harvesting, The collected rain water will be used for watering loiter.

Question 5.
Explain the factors responsible for the depletion of water table.
Answer:
Various factors are responsible for the depletion of water table
(i) Increased Population : Increase in the human population has increased the demand for water. As the number of humans will keep on increasing, the consumption of water will also increase. Sources of water remain limited but consumption keeps on increasing causing great fall in, water table.

(ii) Increasing industries : All industries need water. Inlith increase in human population, the number of industries has also increased; so has increased the consumption of water mainly from ground. This has caused depletion of ground water.

(iii) Agricultural activities : India is a country whose economy depends on the agriculture. With time the land used for cultivation has increased. Therefore, the consumption of water for agricultural purpose has increased. Rains are the main source of water for irrigation. But irregular rain fall has increased the dependence of farmers on the ground water. This has increased the depletion of ground water.

(iv) Lack of water conservation techniques : Main source of/water on earth and for the underground water is the rain. The water of the rain, if conserved can increase the water level. But this is not done due to the lack of rain water harvesting techniques and other water conservation techniques.

Question 6.
Fill in the blanks with the appropriate answers :
(a) People obtain groundwater through _______ and _______ .
(b) Three forms of water are _______, _______ and _______ .
(c) The water bearing layer of the earth is _______.
(d) The process of water seewage into the ground is called _______.
Answer:
(a) wells and handpumps
(b) solid, liquid and vapour
(c) aquifer
(d) infiltration

Question 7.
Which one of the following is not responsible for water shortage?
(i) Rapid growth of industries.
(ii) Increasing population.
(iii) Heavy rainfall.
(iv) Mismanagement of water resources.
Answer:
(iii) Heavy rainfall.

Question 8.
Choose the correct option. The total water
(i) in the lakes and rivers of the world remains constant.
(ii) under the ground remains constant.
(iii) in the seas and oceans of the world remains constant.
(iv) of the world remain constant.
Answer:
(iii) in the seas and oceans of the world remains constant.

Question 9.
Make a sketch showing groundwater and water tube. Label it.
Answer:

Question 10.
Explain how ground water is recharged.
Answer:
The ground water get recharged through the process of infiltration. Infiltration means seeping in water from rivers and lakes into the empty spaces and crack deep below the ground.

Extended Learning-Activities and Projects

Question 1.
Role play
You are a water detective in your school. You have a team of six members. Survey the campus and make a note of the following:
(a) Total number of taps
(b) Number of taps leaking
(c) Amount of water wasted due to leakage
(d) Reasons of leakage
(e) Corrective measures taken
Answer:
Do it yourself.

Question 2.
Groundwater pumped out
Try to find out if there are any hand pumps in your neighbourhood. Go to the owner or the users of a few of these and find out the depth at which they struck water? If there are any differences, think of the probable reason. Write a brief report and discuss it in your class. If possible, visit a place where boring is going on to install a hand pump. Watch the process and find out the depth of the water table at that place. .
Answer:
Do it yourself.

Question 3.
Catching rainwater – Traditional methods
Form groups of 4 to 5 students in the class and prepare a report on the various traditional ways of water harvesting.
Answer:
Do it yourself.

Question 4.
Conservation of water
Carry out a compaign to conserve water at home and in the school. Design posters to remind others of the importance of water resources.
Answer:
Do it yourself.

Question 5.
Create a logo
Hold a competition to create a logo or a symbol depicting water scarcity.
Answer:
Do it yourself.

HBSE 7th Class Science Water: A Precious Resource Important Questions and Answers

Very Short Answer Type Questions

Question 1.
When do we celebrate water day?
Answer:
We celebrate water day on 22nd March every year.

Question 2.
How much minimum water is required by an individual for his daily requirements?
Answer:
According to survey of United Nations every individual require 50 litres of water every day.

Question 3.
What is the main source of water on the earth?
Answer:
Rain is the main source of water on the earth.

Question 4.
Name the main sources of the natural water.
Answer:
Main source of natural water on earth are two : Surface water and underground water.

Question 5.
What are the sources of surface water?
Answer:
Rain water, River and lake water and sea water are the three sources of surface water on earth.

Question 6.
What do you mean by underground water?
Answer:
Water from rain and other sources of surface water seeps inside the earth to fill the empty spaces and crack. It is called underground water.

Question 7.
What do you mean by infiltration?
Answer:
The process of seeping of water into the empty spaces of the ground is called infiltration.

Question 8.
What do you understand by aquifer?
Answer:
Aquifer is the underground water bearing layer of the earth, which is below the water table.

Question 9.
What are main sources of underground water?
Answer:
Main sources of underground water are springs, tubewells, wells, handpumps etc.

Question 10.
What is depletion of water table?
Answer:
Falling level of water at the water table is called depletion of water table.

Question 11.
Name the factors affecting the depletion of water table.
Answer:
Increase in human population, increasing industries and increasing agricultural activities are cause of depletion of water table.

Question 12.
What is water management?
Answer:
Minimum wastage of water is called water management.

Question 13.
What is drip irrigation?
Answer:
It is a technique using narrow tubings to water plants directly at their base without wasting water.

Question 14.
What symplasm in plants show scarcity of water?
Answer:
Wilting and drying.

Question 15.
How can we utilize the rain water?
Answer:
We can store rainwater with help of rain water harvesting techniques.

Short Answer Type Questions

Question 1.
What is the role of water in sustaining life on earth?
Answer:
Water is very important in sustaining life on earth. All the metabolic functions of living beings cannot be ‘performed without water. It provides habital to several animals and plants. So no living organism can survive without water.

Question 2.
What is surface water? What are its source?
Answer:
The water present on the surface of the earth is called the surface water. It can be obtained from rain water, water from rivers and lakes sea water contains maximum surface water.

Question 3.
What is underground water and how can it be obtained?
Answer:
A part of rain water gets percolated into the ground and collect to form a water table. This water is called underground water. Underground water can be obtained from springs, wells and tubewells. Handpumps are also means of obtaining underground water.

Question 4.
What is conservation of water? How can we conserve water.
Answer:
Conservation of water is the wise and fundicious use if, water by us. We can conserve water of harvesting rain water, minimising the wastage of water in houses and industries, using conservation techniques like drip irrigation in agriculture etc. can conserve our fresh water resources.

Question 5.
What do you mean by rainwater harvesting?
Answer:
Collecting and conserving the rain water from the roof tops of the buildings is called rain water harvesting. Water from the roof tops of the houses, industries etc. is collected. It is used directly or allowed to seep into the soil instead of allowing it to flow down. It helps in raising the water table.

Question 6.
What are water-wise habits?
Answer:
Following are the water-wise habits:

• brushing teeth shaving, etc with taps turned off while not using water.
• moking floor instead of washing.
• using small cisterns in toilets.
• using a bucket and mug to take bath instead of bathing under a shower.
• using harvested rain water.

Long Answer Type Questions

Question 1.
List main sources of water explaining each one briefly.
Answer:
There are mainly two sources of natural water.
(i) Surface water : The water which is present on the surface of earth is called the surface water.
It is of three types :

• Rain water : Rain water is the main source of water on the earth. It is the purest form of natural water.
• River and Lake water : The water is rivers and lakes came from rain and melting of snow.
• Sea water : Water from rivers, lakes and streams flow into the sea. Sea water cannot be consumed because it contains various soluble salts.

(ii) Underground Water : A part of rain water predates into the soil and gets collected there. It is called underground water. It can be obtained from the following :

• Spring Water : Some times the water that is collected above the rocks exert pressure. Consequently it comes out from any opening in the earth. It is called spring water.
• Well Water : Water collected inside the earth is called water table. Wells are dug to obtain water, borings are made to instal a hand pump or a tube well.

Question 2.
List the cause and effects of water scarcity.
Answer:
Cause of water scarcity : Following reasons cause the scarcity of fresh water on earth :
(а) Uneven Distribution of water :
There is uneven rainfall on the earth. Some places receive planty of rainfall while others do not receive any rain. Almost about half of the earths land area does not get sufficient rain.

(b) Lack of conservation facilities : Most of the rain water goes waste as it cannot be absorbed in the earth. It runs into other resources like sea, rivers etc. This water otherwise can be percolated into the soil and raise water table. Constructing small reservoirs, artificial lakes and other storage facilities can increase the water table.

(c) Pollution of water : Considerable amount of consignable water gets polluted due to human and industrial activities. This water if not polluted, can be consumed by human beings.

Effects following are the effects of water scarcity :

• acute shortage of water.
• drying up of pumps and lakes.
• failure of crops thus shortage of food.
• death of man and cattle.

Water: A Precious Resource Class 7 HBSE Notes

• Water is a vital natural resource.
• Main sources of natural water are surface water and underground water.
• Rain is the main source of water on the earth.
• Rainwater river and lake water and seawater are the sources of surface water.
• Springwater tubewells hand pumps are the means of obtaining under groundwater.
• level of water under the ground is called water table.
• Infiltration is the seeping of rainwater into the soil.
• Infiltration increases the water table.
• Excess usage of groundwater depletes the water table.
• Rainwater harvesting, drip irrigation etc. helps in conserving water.
• Increase in population, increase in industries, etc. Cause scarcity of water.
• Security of water can snatch away the greenry from the earth.

Haryana State Board HBSE 7th Class Science Solutions Chapter 17 Forests: Our Lifeline Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 17 Forests: Our Lifeline

HBSE 7th Class Science Forests: Our Lifeline Textbook Questions and Answers

Question 1.
Explain how animals dwelling in the forest help it grow and regenerate.
Answer:
Animals help in growing and regenerating forests in many ways. Animals work as the cleaning agents in the forest micro-organisms work on the dead bodies of plants and animals and degenerate them. This also renourishes the soil of the forest with the nutrients broken by the micro-organisms. Animals also help in dispersing the seeds of various plants and help in their pollination. This helps in growing a number of plants, which serve as a food for a number of herbivorous animals. Herbivores helps the carnivores to grow as they serve as food for them. Thus, the flora and fauna grows the in forests.

Question 2.
Explain how forest prevent floods.
Answer:
Forests can absorb a lot of water. The roots of the trees absorb the water and prevent it from flowing away. This helps in preventing floods.

Question 3.
What are decomposers? Name any two of them. What do they do in the forest?
Answer:
Decomposers are the organisms which feed on the dead bodies of the plants and animals. They clean the forests of the decaying dead bodies and replensish the nutrient back to the forest soil e.g. beetles and grubs.

Question 4.
Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere.
Answer:
Plants release Oxygen in the atmosphere during the process called photosynthesis. This oxygen is inhaled by the animals living in the forest for their respirations. During respiration, they release carbon dioxide, which is absorbed by plants. In this way the O₂ – CO₂ cycle goes on in the forest.

Question 5.
Explain why there is no waste in a forest.
Answer:
There is no waste in the forest because decomposers convert all the dead bodies of the plants and animals into the humus. Humus gets added to the soil and no waste is remained.

Question 6.
List five products we get from forests?
Answer:
Products we get from forests:

• We get wood from forests which is used for many purposes like making furniture, paper etc.
• We get medicines from forest.
• We get fodder for our animals from forest.
• We get gum, wax etc.

Question 7.
Fill in the blanks :
(a) The insects, butterflies, honeybees and birds help flowering plants in __________.
(b) A forest is a purifier of __________ and __________.
(c) Herbs form the __________ layer in the forest.
(d) The decaying leaves and animals droppings in a forest enrich the __________.
Answer:
(a) pollination
(b) water and air
(c) lowest layer
(d) soil as humus.

Question 8.
Why should we worry about the conditions and issues related to forests far from us?
Answer:
We should be worried about deforestation, as it would lead to floods, increase in earth’s temperature, depriving animals of their habitats and soil erosion.

Question 9.
Explain why there is a need of variety of animals and plants in a forest.
Answer:
Animals and plants sustain the forest life CO₂ – O₂ cycle goes on in the forest due to animals and plants. Animals convert the dead plants and animals into humus and increase the fertility of soil. All food cycles and food webs need variety of plants and animals.

Question 10.
In Fig. the artist had forgotten to put the labels and directions on the arrows. Mark the directions on the arrows and label the diagram using the following labels :
clouds, rain, atmosphere, carbon dioxide, oxygen, plants, animals, soil, roots, water table.

Answer:
(See. Fig.)

Question 11.
Which of the following is not a forest product?
(i) Gum
(ii) Plywood
(iii) Sealing wax
(iv) Kerosene
Answer:
(iv) Kerosene

Question 12.
Which of the following statements is not correct?
(i) Forests protect the soil from erosion.
(ii) Plants and animals in a forest are not depedent on one another.
(iii) Forests influesce the climate and water cycle.
(iv) Soil helps forest to grow and regenerate.
Answer:
(ii) Plants and animals in a forest are not depedent on one another.

Question 13.
Micro-organisms act upon the dead plants to produce
(i) sand
(ii) mushrooms
(iii) humus
(iv) wood
Answer:
(iii) humus

Extended Learning-Activities and Projects

Question 1.
The Department of Environment is to decide whether some portion of a forest in your area could be cleared for a housing complex. Write a letter to the department explaining your point of view as a concerned citizen.
Answer:
Do it yourself.

Question 2.
Visit a forest. Here is a list of points that would make your visit more fruitful.
(а) Make sure that you have permission to go into the forest.
(b) Make sure that you can find your way around. Get a map and go along with some one who is familiar with the area.
(c) Keep a record of the things you see and do. Observations make the visit interesting. Sketches and photographs are useful.
(d) You may record bird calls.
(e) Collect different kinds of seeds or hard fruits like nuts.
(f) Try to recognise various types of trees, shrubs, herbs, etc. Make lists of plants from different places in the forest and of diferent layers. You may . not be able to name all the plants, but it is worth recording and seeing where they grow. Make a record of approximate heights of plants, crown shape, bark texture, lea size, and flower colour.
(g) Learn to recognise the animal’s droppings.
(h) Interview the forest officials and the people of surrounding villages and other visitors.
Answer:
Do it yourself.

HBSE 7th Class Science Forests: Our Lifeline Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Write three things we get from forests.
Answer:
Wood, gum and medicine

Question 2.
What is a forest?
Answer:
Forest is a place hosting a number of plants and animals.

Question 3.
Which plants constitute canopy in forests?
Answer:
Tall and giant trees.

Question 4.
Which plants constitute the understoreys in forest?
Answer:
Shrubs, tall grasses and small trees.

Question 5.
What is the basic unit of any food chain?
Answer:
Plants.

Question 6.
Draw any simple food chain going on in the forest.
Answer:
Grass → insects → frog snake → eagle.

Question 7.
What is Humus?
Answer:
Humus is a dark coloured substance which is formed from the dead bodies of plants and animals.

Question 8.
What are decomposers?
Answer:
The micro-organisms which decompose the dead bodies of the plants and animals are called decomposers.

Question 9.
Who helps in the dispersal of seeds of plants in the forest?
Answer:
Animals and wind helps in dispersal of seed.

Question 10.
How does forest help in preventing floods?
Answer:
Forests absorb the rain water in the soil and prevent the floods.

Question 11.
Why the noise pollution is less in the areas situated near the forests?
Answer:
Forest absorb the noise and prevent noise pollution.

Question 12.
What is deforestation?
Answer:
Cutting and destroying the forest is called deforestation.

Question 13.
What are the effects of deforestation?
Answer:
Floods, rising temperature, scarcity of food and wood and disturbed food chains are the results of deforestation.

Question 14.
How can we preserve our forest wealth?
Answer:
We can preserve our forest wealth by planting more and more trees.

Question 15.
What do you mean by afforestation?
Answer:
Planting more trees is called afforestation.

Short Answer Type Questions

Question 1.
Write any four products we get from forests.
Answer:

• We get wood from the forests.
• We get medicinal plants from the forests.
• We get gum and paper from the forests.
• We get food from forests in form of plants and animals.

Question 2.
What kind of flora is found in the forest?
Answer:
We can find wide variety of plants in the forest. We can find huge and giant trees. We can find small trees and shrubs. Various small plants like shrubs and grasses are also found in the forest.

Question 3.
What is a food chain?
Answer:
All the living components of the forest depend upon each other for their food. This interdependence of one organism on other for food is called a food chain.

Question 4.
What do you mean by micro-organisms?
Answer:
Micro-organisms as the name suggest are very small organisms. These organisms are so small that they cannot be seen with naked eyes. They can be seen under a microscope only e.gt bacteria, yeast etc.

Question 5.
What are decomposers?
Answer:
Decomposers are the micro-organisms which feed on the dead bodies of the plants and animals. They convert the dead bodies of these plants and animals into fertile humus.

Question 6.
How forests help in bringing rain?
Answer:
Trees absorbs water from the soil through their roots. They then release the excess of water through the process of transpiration in the form of water vapours. These water vapours form clouds and clouds bring rain.

Long Answer Type Questions

Question 1.
List the utility of forests.
Answer:
Forests are indispensible for us. They play an important role in our lives and in our environment.
Following are the importance of the forests:
(i) Forests give us a number of products which are very useful for us. They provide us wood. Wood is used to make furniture, house, toys, sports and fuel. Forests give us many medicinal plants. They give us gum, wax, catechu fruits, fodder and many more things.

(ii) Forests help in causing rains.

(iii) Forests maintain the temperature of the earth.

(iv) Forests maintain the O₂ – CO₂ cycle going on in the environment.

(v) Forests maintain the water-cycle going on in the environment.

(vi) Forests prevent many climate disaters like flood and draughts.

(vii) Forest provide shelter to a lot of wild life.

Question 2.
How forest sustain various variety of animals?
Answer:
Forests have different types of animals in it. Herbivores, Carnivores and Scvengers etc. Forest provide all the conditions necessary for their living. They get their food in the forest itself. The herbivores get their food in the form of plants. Carnivores eat the herbivores and systain their lives. Scavengers live on the dead bodies of all these animals and plants. Various invisible micro-organisms also live in forest. These micro-organisms are called decomposers. They convert the dead remains of animals and plants into the fertile humus.

Question 3.
What is the importance of scavengers and decomposers in the forests?
Answer:
A number of animals and plants live in forests. When they die, no body cremate their dead bodies. They keep on lying there. Scavengers like vultures, eagles etc. eat their dead bodies. They eat the flesh and other soft orgAnswer: The rest of the dead bodies are broken down by various micro-organisms called decomposers. They decompose the dead bodies of animals and plants into a dark substance called humus which is very nutritious for the soil. If scavengers and decomposers do not eat the dead bodies of animals and plants, the forest would become a big store of dead bodies and unfit for any wild life. This would disturb the whole environmental balance.

Forests: Our Lifeline Class 7 HBSE Notes

• A major part of our land is covered with forest.
• Forests are very important renewable resource.
• Forest help in maintaining the CO₂-O₂ cycle in our environment.
• They serve as a habitat to a number of plants and animals.
• Forests are indispensible for human life.
• A lot of variety of small and big plants can be found in forests.
• Different species of animals and birds live in the forest.
• All the biotic and abiotic components of the forest are interrelated with each other.
• All these components serve as complementary to each other.
• Forests save the soil erosion and maintain the water table beneath the soil.
• They cause the rains and maintain the water cycle.

Haryana State Board HBSE 7th Class Science Solutions Chapter 4 Heat Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 4 Heat

HBSE 7th Class Science Heat Textbook Questions and Answers

Question 1.
State similarities and differences between the laboratory thermometer and the clinical thermometer.
Answer:
Laboratory Thermometer: While performing experiments involving the measurement of temperature in the laboratory, a mercury thermometer is used. It is a thermometer having graduations marked on the Celsius scale from 0°C to 100°C.

The difference between the lower and upper fixed points is called range of the thermometer. The range of a mercury thermometer is 100°C. A mercury thermometer having graduations from 0°C to 100°C is shown in figure 4.8.

Clinical Thermometer:
To measure the temperature of a person running fever, doctor uses a thermometer known as Clinicdl Thermometer. It is a specially designed mercury thermometer and is used in the clinics and hospitals by doctors to measure human body temperature.

In construction, it differs from laboratory thermometers, in the sense that a kink or constriction is provided in the stem just above the bulb. Because of this kink, mercury doesn’t fall back into the bulb when clinical thermometer is taken out of the mouth of a patient to know the temperature. A jerk is given to the thermometer so that it is set again for measuring human body temperature. The temperature interval marked on the clinical thermometers ranges from 35°C to 43°C.

Question 2.
Give two examples each of conductors and insulators of heat.
Answer:
Conductors: aluminium, iron
Insulators: plastic, wood

Question 3.
Fill in the blanks:
(a) The hotness of an object is, is determined by its …………… .
(b) Temperature of boiling water cannot be measured by a …………… thermometer.
(c) Temperature is measured in degree ……………. .
(d) No medium is required for transfer of heat by the process of ………….. .
(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of …………. .
(f) Clothes of …………… colours absorb heat better than clothes of light colours.
Answer:
(a) Touching
(b) Clinical
(c) Celsius
(d) Radiation
(e) Conduction
(f) Dark

Question 4.
Match the following:

Answer:

Question 5.
Discuss why wearing more layers of clothing of during winter keeps us warmer tljian wearing just one thick piece of clothing?
Answer:
More layers of clothing keep us warm in winters as they have a lot of space between them. This space gets filled up with air. As air is a bad conductor, it does not allow the body heat to escape out.

Question 6.
Look at Fig. 4.10. Mark where the heat is being transferred by conduction, by convection and by radiation.
Answer:

Question 7.
In places of hot climate it is advised that the outer walls of houses be painted white. Explain.
Answer:
In places of hot climate it is advised that the outer wail of houses be painted white because white colour do not radiate heat easily.

Question 8.
One litre of water at 30°C is mixed with one litre of water at 50°C. The temperature of the mixture will he:
(a) 80°C
(b) More than 50°C but less than 80°C
(d) 20°C
(d) Between 30°C and 50°C
Answer:
(b) More than 50°C but less than 80°C

Question 9.
An iron ball at 40°C is dropped in a mug containing water at 40°C. The heat will:
(a) Flows from iron ball to water.
(b) Not flow from iron ball to water or from water to iron ball.
(c) Flows from water to iron ball.
(d) Increase the temperature of both.
Answer:
(a) flows from iron ball to water.

Question 10.
A wooden spoon is dipped in a cup of ice-cream. Its other end:
(a) Becomes cold by the process of conduction.
(b) Becomes cold by the process of convection.
(c) Becomes cold by the process of radiation.
(d) Does not become cold.
Answer:
(d) does not become cold.

Question 11.
Stainless steel pans are usually provided with copper bottoms. The reason for this could be that:
(a) Copper bottom makes the pan more durable.
(b) Such pans appear colourful.
(c) Copper is a better conductor of heat than the stainless steel.
(d) Copper is easier to clean than the stainless steel.
Answer:
(c) Copper is a better conductor of heat than the stainless steel.

Extended Learning – Activities And Projects

Question 1.
Go to a doctor or your nearest health centre. Observe the doctor taking temperature of patients. Enquire:
(a) Why he/she dips the thermometer in a liquid before use.
(b) Why the thermometer is kept under the tongue.
(c) Whether the body temperature can be measured by keeping the thermometer at some place other than mouth.
(d) Whether the temperature of different parts of the body is the same or different. You can add m.ore questions which come to your mind.
Answer:
Do yourself. You can take help of your family doctor.

Question 2.
Go to a veterinary doctor (a doctor who treats animals). Discuss and find out the normal temperature of domestic animals and birds.
Answer:
Do yourself.

Question 3.
Wrap a thin paper strip tightly around an iron rod. Try to burn the paper with candle while rotating the iron rod continuously. Does it burn? Explain your observation.
Answer:
Do yourself.

Question 4.
Take two similar transparent glass bottles having wide mouths. Put a few crystals of potassium permaganate or pour a few drops of ink in one bottle. Fill this bottle with hot water. Fill the other bottle with cold water. Cover the cold water bottle with a thick piece of paper such as a postcard. Press the postard firmly with one hand and hold the bottle with the other hand. Invert the bottle and place it on top of the hot water bottle. Hold both the bottles firmly. Ask some other person to pull the postcard. Observe what happens. Explain.
Answer:
Do yourself.

HBSE 7th Class Science Heat Important Questions and Answers

Very Short Answer Type Questions

Question 1.
What is heat?
Answer:
The energy transferred from one body to another body due to a temperature difference between them is called heat.

Question 2.
Define temperature.
Answer:
Temperature is the degree of hotness or coldness of a body.

Question 3.
Define thermometer.
Answer:
A device used for measuring the temperature of different objects is called a thermometer.

Question 4.
Hot water bottles are used for fermentations. Explain why?
Answer:
Hot water bottles are used for fermentation as the water does not cool quickly due to its large specific heat capacity.

Question 5.
When equal amount of air, iron and oil are heated from 15°C to 25°C. List them in the order of increasing expansion.
Answer:
Iron, oil, air.

Question 6.
Name any four substances which expand on heating.
Answer:
Aluminium, steel, iron and copper.

Question 7.
Name any two substances which have negligible changes in length on heating.
Answer:
Pyrex glass, Invar.

Question 8.
Name two substances which contract on heating?
Answer:
Ice, Bismuth.

Question 9.
Do all liquids expand when heated or is there any exception?
Answer:
Yes, below 4°C when heated, water contract in stead of expanding.

Question 10.
Which substances has the highest heat capacity?
Answer:
Water.

Question 11.
What is the temperature of a normal human being on the Celsius scale?
Answer:
The temperature of a normal human being on the Celsius scale is 37°C.

Question 12.
Name the thermometer used for measuring the temperature of the human body.
Answer:
The thermometer used to measure the temperature of a human body is called clinical thermometer.

Question 13.
Define convection.
Answer:
The phenomenon due to which particles of a medium actually move to the source of heat energy and then move away from it after absorbing heat energy is called convection.

Question 14.
Why is convection not possible in solids?
Answer:
The molecules of a solid are held strongly due to intermolecular forces. As these molecules cannot travel to the source of heat energy, convection is not possible in case of solids.

Question 15.
What is ventilation?
Answer:
The process by which impure and warm air inside a room is continuously replaced by fresh air from outside is called ventilation.

Question 16.
What do you understand from the term lower standard point?
Answer:
The 0°C correspondence to the temperature of pure melting ice and is called the lower standard point.

Question 17.
What do you understand by upper standard point?
Answer:
100°C corresponds to the temperature of pure boiling water and is called the upper standard point.

Question 18.
Define conduction.
Answer:
The process of transmission of heat energy in solids without the actual movement of particles from their position is called conduction.

Question 19.
Give two examples to show that heat caused biological changes.
Answer:
(i) Conversion of ‘gur’ into alcohol.
(ii) Conversion of milk into curd.

Question 20.
Why is ice wrapped in gunny bags?
Answer:
Gunny bags have a number of fine pores, filled with air. Air being a bad conductor of heat does not allow the external heat to go in and melts the ice.

Question 21.
Why is tea generally served in China clay cups and plates?
Answer:
Because the China clay is bad conductor of heat and checks the heat conduction from the tea to the surroundings and thus keeps the tea hot.

Question 22.
By which of the processes (conduction, convection, radiation), it is not possible to transfer heat?
(i) In a vacuum
(ii) Through the solid material.
Answer:
(i) Conduction and convection
(ii) Convection and radiations.

Question 23.
Why do we use cooking utensils made of metals and alloys?
Answer:
Metals and alloys are good conductors of heat so that the heat from the flame is conducted to the food inside quickly and efficiently.

Question 24.
Is medium necessary for the transference of heat by radiations?
Answer:
No, medium is not necessary for the transference of heat by radiation.

Question 25.
Why do we feel warm while standing beside a burning furnace?
Answer:
When we stand beside a burning furnace, we feel warms, because of the heat radiation coming from the furnace.

Question 26.
Firemen wear helmets made from brass polished from outside. Why?
Answer:
Brass polished helmets reflects most of the heat and absorbs only a very little part of it when they fight against a fire.

Question 27.
When does the conduction of heat stop in two bodies in contact?
Answer:
The conduction of heat stops in two bodies in contact when both attain the same (equal) temperature. In this position they have no temperature difference.

Question 28.
Why is the handle of a press made of ebonite or wood?
Answer:
The handle of press is made of ebonite or wood, because ebonite and wood are bad conductors of heat. So the heat does not reach in our body.

Question 29.
Define radiation.
Answer:
The transfer of heat energy from a hot body to a cold body directly, without heating the space in between the two bodies is called radiation.

Question 30.
Define insulators.
Answer:
The materials which do not allow heat to pass through them easily are poor conductors of heat such as plastic and wood. Poor conductors are known as insulators.

Question 31.
What is thermos flask?
Answer:
Thermos flask is a device in which heat losses due to conduction, convention and radiation are minimised.

Short Answer Type Questions

Question 1.
The cooking utensils are made of metals like aluminium or copper while their handles are made of wood. Why?
Answer:
The cooking utensils are made of metals like aluminium or copper because these metals are good conductors of heat so they help in the transfer of heat.

The handles of cooking utensils are made up of bad conductors such as wood, plastic etc. As the handles made of bad conductors do not get heated up while cooking, we can hold them easily.

Question 2.
Kites and eagles fly without flapping their wings. Why?
Answer:
During the day, hot air surrounding the land gradually rises up and a convection air current develops. Kites and eagles move along this rising current without flapping the wings to fly high up in the sky.

Question 3.
Why do the birds puff up their feathers in winter?
Answer:
The birds puff up their feathers in winter, because in doing so they trap large amount of air, which in turn acts as an insulator and does not allow their body heat to flow out.

Question 4.
Explain briefly the formation of air currents.
Answer:
In coastal areas, during the day, the cool air blows from sea towmrds the land called sea breeze. During the night, the cool air blows from land to sea called the land breeze. This happens because of convection air currents. At night, land cools down much faster than sea. So, sea is warmer than land and the air current blows from land to sea. During the day, land is hotter than sea. As a result, the air rises up and cold air from sea blows towards the land to take its place.

Question 5.
Cement or concrete floors are made in pieces with metals or glass strips in between. Give reasons.
Answer:
It is done to allow for the expansion in summer and contraction in winter. If cement or concrete floors are made out in one continuous pieces. It would develop crackes due to contraction and expansion.

Question 6.
Room heaters have shiny reflectors. Why?
Answer:
Room heaters have shiny reflectors as the shiny surface absorbs very little heat. They reflect all the heat which makes the room heaters more effective.

Question 7.
Why is the handle of a pressure cooker covered with thick plastic?
Answer:
The handle of a pressure cooker covered with thick plastic, because plastic is a bad conductor of heat. Hence, the heat from the hot cooker does not flow to the handle, with the result that we can hold easily.

Question 8.
The desert sand is very hot in the day and very cool at night. Why?
Answer:
The desert sand has low specific heat capacity. So sand gets very hot in day time. During the night sand cools more quickly due to cold air which moves towards the sea.

Question 9.
Why is the handle of a metallic kettle covered with strips of cane?
Answer:
Cane strips is bad conductor of heat. Therefore, it cannot get heated when water is boiled in kettle. Therefore, the handle of a metallic kettle is covered with cane strips.

Question 10.
Why does the handle of an iron made of ebonite or wood?
Answer:
Ebonite or wood is a bad conductor of heat. Therefore, the heat from the iron is not conducted to the hand.

Question 11.
How does a blanket keep you warm in a cold night, even though it is not a source of heat?
Answer:
The blanket is made of wool, which is a bad conductor of heat. It has fine pores in which air is trapped which is also a bad conductor of heat. They do not allow heat to escape from our body to the surroundings. Therefore, the blanket keeps our body warm in winter.

Question 12.
Why are cloudy nights warmer than the clear nights?
Answer:
Cloudy nights are warmer than clear nights due to the fact that the heat which is radiated by the earth is again reflected back by the clouds. While on the other hand this phenomenon is not possible when the night is clear.

Question 13.
How are had conductors of heat useful in our daily life?
Answer:
Bad conductors are used for holding hot utensils in the kitchen. Bricks and mud which are bad conductors are used in building houses, especially in the ruler. regions. They keep houses warm in winter and cool in summer. The feathres of birds, hair and fur of animals keep them warm in winter, as they are bad conductor of heat.

Question 14.
Why do we wear woolen clothes in winter?
Answer:
Woolen clothes have fine pores filled with air. Wool and air are bad conductors of heat They do not allow heat of our bodies to escape out. Therefore woolen cloth keep the body warm in winter. And for the same reason we wear woolen cloth in winter.

Long Answer Type Questions

Question 1.
Describe briefly the process of conduction.
Answer:
Heat travels through solids by conduction only. The process of transmission of heat energy in solids without the actual movement of particles from their position is called conduction. Conduction takes place under the following conditions:
(i) A material medium that is compact.
(ii) No movement of any particle in the medium.
Thus, solids transmit heat though conduction. When a solid substance is heated, the particles that become hot start vibrating and pass on the excess energy to the neighbouring particles. This process continues till the whole body is heated. However during such an energy transfer, a particle does not change its position. Hence, heat is carried without the bodily movement of the particles.

There are some solids which allow the heat to pass through them. Such substances are called the conductors. Almost all metals such as iron, copper, silver, aluminium etc. are good conductors. The substances which do not allow the heat to pass through them are called the insulators. Wood, plastic, wool, clay etc. are bad conductors.

Question 2.
Write an experiment to prove that heat radiations can travel through vacuum.
Answer:
Take a flat bottomed flask. In the mouth of the flask fix a rubber stopper having two holes. Pass a thermometer through one hole and a glass tube with stopper through the other hole.

Remove air from the flask, by connecting to a vacuum pump. Record the temperature from the thermometer. Place the flask in bright sunlight or in front of an electric heater. It is observed that the thermometer records a rise in temperature. Thus, the experiment proves that transference of heat by radiaton requires no medium.

Question 3.
Explain the working of a thermos flask.
Answer:
Thermos flask is a special kind of flask for keeping liquids. It prevents loss or gain of heat by any of the three methods. It keeps liquid warm or cold for a long time. It was invented by Sir James Dewan in 1893.

It consists of a double-walled glass-cylinder. A vacuum is created in the space between the double walls. The two inner surfaces of glass walls are silvered. The flask is placed on a spring within a non-conduction cylindrical case to protect it from jerks and breakages. The gaps between flask and outer casing is packed with felt pads. The mouth of the flask is finally closed with a cork.

Since the container is made of glass which is a bad conductor of heat and therefore, the loss or gain of heat due to conduction is prevented. As there is vacuum between the double walls, it prevents transmission of heat by convection. Due to silvering of the inner surfaces, the heat loss by radiation is prevented. The cork and the felt pads also help to preserve the heat inside the flask. So, the hot liquids like tea, coffee, etc. remain hot and cold liquids like water, juice, etc. remain cold for a long time.

Question 4.
Write five applications of radiation.
Answer:
Applications of radiation:
(i) The base of cooking utensils is painted black so that it can absorb more heat and hence cooking is done fast.
(ii) Dark clothes are worn in winters as they absorb more heat from the sunlight and keep our body warm.
(iii) White clothes are worn in summer as they absorb very little heat and keep us cool.
(iv) Room-heaters have shiny reflectors as the shiny surface absorbs very little heat. They reflect all the heat which makes the room- heaters more effective.
(v) Crockeries are polished and painted white from outside so that they do not radiate heat easily.

Question 5.
Describe the process of radiation. How is it different from conduction and convection?
Answer:
Radiation is a process of transmission of heat in which heat energy travels in straight lines from hotter to cooler regions without the help of any intervening medium. It means that this process is different from the other two as it does not need any medium like conduction or convection. Radiation can take place in a vaccum. For example, heat from the sun reaches us through the outer space (vacuum) by means of radiation in the form of electromagnetic waves.

Differefnbe between radiation, conduction and convection:

Heat Class 7  HBSE Notes

• Our sense of touch is not always a reliable guide to the degree of hotness of an object.
• Heat: Heat is a form of energy which produces in us sensation of warmth. It causes hotness or coldness sensation in our body.
• Temperature: Temperature tells how hot a body is? Temperature of a body is the degree of hotness or coldness of the body.
• Heat flows in the direction of fall of temperature. Heat can be converted to other forms of energy like sound, light, mechanical energy etc. Other forms of energy can also be converted to heat energy.
• Effects of heat:
  (i) The object becomes hot.
  (ii) The object may expand in size.
  (iii) The object may change in state.
  (iv) Heat can speed up chemical reaction.
• Temperature is measured by a device called thermometer.
• The thermometer that measure our body temperature is called a clinical thermometer. The range of this thermometer is from 35°C to 42°C. For other purposes, we use the laboratory thermometers. The range of these thermometers is usually from 10°C to 110°c.
• The laboratory thermometer used in laboratories. It is called Celsius thermometer. It has one hundred markings on it.
• The melting point of pure ice is called lower standard point. Its value is 0°C.
• The boiling point of pure water is called upper standard point. Its value is 100°C.
• Transfer of heat: Heat flows from one body to another body by temperature difference. The flow of heat is from higher temperature to lower temperature. There are three different ways of heat transfer: conduction, convention and radiations.
• Conduction of heat: The process in which heat is handed over from one particle to another in the direction of fall of temperature without the actual movement of the particles of the medium is called conduction.
  
• Good conductor of heat: The materials which allow heat to pass through them easily, are called good conductor of heat. For example, silver, copper, aluminium, mercury etc. are good conductors of heat.
• Bad conductor of heat: The materials which do not easily allow heat to pass through them are called bad conductors of heat or insulators. Wood, plastics, mud, cork, cotton, ebonite, asbestos, most gases and liquids are bed conductor of heat.
• Convention of heat: Convention is a process by which heat is transferred from one part of a substance to another part through the actual movement of its constituents particles (atoms or molecules). Only liquids and gases convert heat. A solid cannot do so because solids do not flow like liquids or gases do.
• Radiation of heat: The process by which heat travels from one body to another without the intervention of any material medium is known as radiation.
  All hot objects transfer heat by radiation. Radiation does not require either a conducting medium or a convecting fluid. The sun transfers heat in all directions through the process of radiation. The radiations absorbed or emitted by a body depends upon the colour of the body.
  
• Thermos Flask (Vacuum Flask): Thermos flask is used to keep things warm and cold. It consists of a double walled glass flask, having vacuum between the walls, kept inside metallic case with the cork supporters.
  The outer and inner surfaces of the glass flask are highly silvered. The mouth of flask is fitted with air tight cork.
  
• The vacuum between the two walls of the flask prevents heat transfer by conduction or convection.
• The silver coating of the walls of the vessels reflects back heat radiations. Thus heat by radiation can neither enter inside the flask nor go out of the flask.
• The air-tight cork, which is a bad conductor of heat prevents any loss of heat by conduction or convection.
• Some heat may be transferred by conduction through thin glass walls at the neck and the poorly conducting cork.
• The total transfer of heat is very-very small, thus hot or cold liquid kept inside will keep its temperature for a long time.

Haryana State Board HBSE 7th Class Science Solutions Chapter 3 Fibre to Fabric Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 3 Fibre to Fabric

HBSE 7th Class Science Fibre to Fabric Textbook Questions and Answers

Question 1.
You must be familiar with the following nursery rhymes:
(i) Baa baa black sheep, have you any wool
(ii) Mary had a little lamb, whose fleece was white as snow
Answer the following:
(a) Which parts of the black sheep have wool?
(b) What is meant by the white fleece of the lamb?
Answer:
(a) The Hair (fleece) of the black sheep have wool.
(b) The white fleece is the v/hite hair of the lamb.

Question 2.
The silkworm is (a) a caterpiller, (b) a Larva. Choose the correct option.
(i) a
(ii) b
(iii) both a and b
(iv) neither a nor b.
Answer:
(iii) both a and b.

Question 3.
Which of the following does not yield wool?
(i) Yak
(ii) Camel
(iii) Goat
(iv) Woolly dog.
Answer:
(iv) Woolly Dog.

Question 4.
What is meant by the following terms?
(i) Reasing
(ii) Shearing
(iii) Sericulture
Answer:
(i) The fleece of the sheep alongwith a thin layer of skin is removed from its body. This process is called shearing.
(ii) Silk fibres are also animal fibres. Silkworms spin the ‘silk fibres’.
(iii) The rearing of silkworms for obtaining silk is called sericulture.

Question 5.
Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, ………………. , sorting, ………………. , ………………. , ………………. , ………………. .
Answer:
Shearing, scouring, sorting, drying, dying, spinning, weaving.

Question 6.
Make sketches of the two stages in the life history of the silk moth which are directly related to the production of silk.
Answer:

(a) Female silkworm moth with eggs

Question 7.
Out of the following, which are the two terms related to silk production? Sericulture, Floriculture, Moriculture, Apiculture, Silviculture
Hints:
(i) Silk production involves cultivation of mulberry leaves and rearing silkworms.
(ii) Scientific name of mulberry is Morus alba.
Answer:
Sericulture, Moriculture.

Question 8.
Match the words of column I with those given in column II.

Answer:

Question 9.
Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.

Answer:

Extended Learning-Activities And Projects

Question 1.
Paheli wants to know the maximum length of continuous silk thread that can be obtained from a cocoon.
Answer:
Do yourself. Take help to your teacher.

Question 2.
Boojho wants to know why caterpillars need to shed their skin when they grow bigger but we humans do not.
Answer:
Do yourself.

Question 3.
Boojho wants to know why caterpillars should not be collected with bare hands.
Answer:
Do yourself.

Question 4.
Paheli wanted to buy a silk frock and went to the market with her mother. There they found that the artificial (synthetic) silk was much cheaper and wanted to know why Do you know why? Find out.
Answer:
Do yourself.

Question 5.
Someone told Paheli that an animal called ‘Vicuna’ also gives wooljl Can you tell her where this animal is found? Look for this in a dictionary or an encyclopaedia.
Answer:
Do yourself.

Question 6.
When handloom and textile exhibitions are held, certain stalls display real moths of various varieties of silk and their life histories. Try and visit these stalls with elders or teachers and see these moths and stages of their life history.
Answer:
Do yourself.

Question 7.
Look for eggs of any moth or butterfly in your garden or park or any other place full of plants. They look like tiny specks (dots) laid in a cluster on the leaves. Pull out the leaves containing eggs and-place them in a cardboard box. Take some leaves of the same plant or another plant of the same variety, chop them and put them in the box. Eggs will hatch into caterpillars, which are busy eating day and night. Add leaves everyday for them to feed upon. Sometimes you may be able to collect the caterpillars. But be careful. Use a paper napkin or a paper to hold a caterpillar.
Observe everyday. Note the
(i) number of days taken for eggs to hatch
(ii) number of days taken to reach the cocoon stage and
(iii) to complete life cycle. Record your observations in your notebook.
Answer:
Do yourself.

HBSE 7th Class Science Fibre to Fabric Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Name the sources of obtaining fibres.
Answer:
The sources of obtaining fibres are plants and animals.

Question 2.
Name some wool yielding animals.
Answer:
Some wool yielding animals are: sheep, angora goat, goat, yak, camel, llama, alpaca.

Question 3.
What is shearing?
Answer:
The fleece (hair) of the sheep alongwith a thin layer of skin is removed from its body. This process is called shearing.

Question 4.
From where do we get wool and silk fibres?
Answer:
Wool and silk fibres are obtained from animals. Wool is obtained from hair of animals ; as sheep hairs and silk fibtes are obtained from silk worm.

Question 5.
What is wool?
Answer:
Wool is the common name of applied to soft curly fibres obtained chiefly from the fleece of domesticated sheep.

Question 6.
What determines the fineness of wool?
Answer:
The number of crimps per centimetre determines the fineness of wool fibre.

Question 7.
Name two breeds of sheep which has finest fleece?
Answer:
Two breeds of sheep which has finest fleece are: merino and Karakul.

Question 8.
Name two systems used in the processing of wool.
Answer:
Two system used in the processing of wool are:
1. Woollen system
2. Worsted system.

Question 9.
Name two substance removed from row wool, before manufacturing yam.
Answer:
Two substance removed from raw wool, before manufacturing yarn are:
1. Yolk
2. Suint.

Question 10.
What is woolmark?
Answer:
Woolmark is the mark of standardisation given to woollen yarns and woollen products. This mark has been instituted by International Wool Secretariat (I.W.S.) located in North Yorkshire (U.K.).

Question 11.
What are the uses of wool?
Answer:
Wool is used for making fabrics, shawls, blankets, carpets, felt and upholstery.

Question 12.
Write the properties of wool fibre.
Answer:
Wool fibre is considerably resilient, has high tensile strength, light weight and is heat insulator.

Question 13.
Name the domesticated moth whose larva produces silk.
Answer:
Silk is obtained from the cocoon of the pupa of mulberry silk moth.

Question 14.
Name the plant on which silk larva feeds.
Answer:
Silk larva feeds on the leaves of mulberry tree.

Question 15.
Name the person responsible for the discovery of silk.
Answer:
Silk was discovered by Xi-Ling-Shi, the bride of Chinese emperor Huang Di, in about 3000 B.C.

Question 16.
Name the strongest variety of silk.State whether the variety you have named is wild silk or domesticated silk.
Answer:
The strongest variety of silk is “Muga”. It is the variety of wild silk.

Question 17.
Name the different varieties of processed silk.
Answer:
Organize, Gepe, Tram and Thrown Singles are different, varieties of processed silk.

Question 18.
Give uses of silk, other than for making dresses.
Answer:
Other than for making dresses, silk is used for items such as parachutes, bicycle tyres, bullet proof vests and non-absorbable sutures in surgery.

Question 19.
What is sericulture?
Answer:
The science of raising silkworms, so as to obtain silk cocoons, is called sericulture.

Question 20.
Where are sheep reared in India?
Answer:
In India sheep are reared in Sub-Himalyan region which has a cooler climate.

Question 21.
Differentiate between staple fibres and filament fibres.
Answer:
The fibres like cotton, jute, and wool are short in length. Silk however, is the longest natural fibre. The short fibres are known as the stable fibres, where as long fibres are known as the filament fibres.

Question 22.
Name some Indian breeds of sheep.
Answer:
Some Indian breeds of sheep are Lohi, Rampur bushair, Nali, Bakharwal, Marwari, and Patanwadi.

Question 23.
What is reeling of silk?
Answer:
A pile of cocoons is used for obtaining silk fibres. This process is called reeling of silk.

Short Answer Type Questions

Question 1.
Differentiate between woollen yarn and worsted yam.
Answer:
The woolen yarn is made from the woolen fibres of mixed lenghts. These fibres are, carded and spun to form a woolen yarn. The articles made from this yarn do not have smooth finished surface.

In the worsted yarn, only the long fibres are used. They are formed into smooth compact strands and are then spun to form woolen yarn. The articles made from these have smooth finished surface.

Question 2.
What do you mean by the term ‘weighting of sillf’?
Answer:
Silk when unwound from the cocoon is covered with a sticky substance. This has to be removed by washing process. As a result, silk loses about 20% of its weight. To make up for this loss some manufactures dip silk in metallic salt solution. This is known as weighting of the silk. This silk is weaker than pure silk. It than not be cleaned properly. This silk is of substandard quality and hence, deceives the buyers.

Question 3.
What is raw silk? How is it produced?
Answer:
After brushing, filaments from four to eight cocoons are joined and twisted. They are then combined with a number of other similarly twisted filaments, to make a thread that is wound on a reel. The thread is called raw silk.

It usually consists of 48 individual silk fibres. When each cocoon is unwound, it is replaced by another cocoon.Unlike the threads spun from other natural fibres, such as cotton or wool, the silk thread is made of extremely long fibres.

Question 4.
Name and describe any two types of silk threads used in the making of silk cloth.
Answer:
Two types of silk threads used in the making of silk cloth are:
1. Organzine:
Organzine thread is made by giving raw silk thread a preliminary twist in one direction and then twisting two or more of these threads in the opposite direction at rate of about 4 turns / cm.
2. Crepe: Crepe is similar to organzine, but it twisted to much greater extent, usually, 16 to 32 turns / cm.

Question 5.
Why do the wool fibres have greater bulk as compared to other fibres?
Answer:
The scales and crimps in the wool fibre make it possible to spin and felt the fleece. They help the individual wool fibres “grab” each other so that they stay together. Because of the crimp, wool fabrics have a greater bulk; than other textiles. They can retain lot of air and hence wool fabrics are good insulators of heat. The heat insulation also works boths ways.

Question 6.
Name the some breeds of sheep reared in our country. Also, indicate the quality and texture of the fibres obtained from them.
Answer:
Some Indian breeds of sheep:
Answer:

Question 7.
Write short note on ‘wool production’.
Answer:
Australia is the world’s largest producer of raw wool and contributes 29% of total world supply. Other leading producers of wool are former Soviet Republics, New Zealand, China, Argentina, South Africa and Uruguay. In India sheep are reared in Sub-Himalayan regions which has a cooler climate. The sheep which are reared in Rajasthan have poor quality of wool and are mainly reared for meat.

Long Answer Type Questions

Question 1.
What is raw silk? How is it produced?
Answer:
After brushing, filaments from four to eight cocoons are joined and twisted. They are then combined with a number of other similarly twisted filaments, to make a thread that is wound oft a reel. The thread is called raw silk. It usually consists of 48 individual silk fibres. When each cocoon is unwound, it is replaced by another cocoon. Unlike the threads spun from other natural fibres, such as cotton or wool, the silk thread is made of extremely long fibres. About 5,500 cocoons are required to produced 1 kg of raw silk.

Question 2.
What is sericulture? Explain in brief.
Answer:
The silk is obtained from cocoon. When the complete cocoon is formed, they are collected. The pupa inside the cocoon is killed by treating the cocoons with boiling water. This hot water not only kills the cocoons but also dissolves the sticky substance that holds the cocoon filaments in place. The cocoons are, thereafter, dried and brushed. This removes the outer portion that is made of coarse filaments.

The thread is then unwound from the cocoons and is wound on a reel. The thread is called the raw silk. It generally consists of 48 individual silk fibres. The silk filaments are unwound from cocoon in a manufacturing plant known as filature. The silk thread is made up of extremely long fibres. About 5,500 silkworms are needed to produce 1 kg of raw silk. The breeding and management of silk moths for producing silk is known as sericulture.

Question 3.
Explain briefly the process of wool manufacturing.
Answer:
In order to make different articles, the raw wool is processed which starts with sorting of the fibres. The fibres are sorted on the basis of length, fineness, etc. The sorting is followed by cleaning 6f the fibres. Using a suitable detergent, the fibres are cleaned from lanolin (an oily substance) and suint (the dried perspiration of sheep). The cleaned wool fibres are then dried and disentangled. Thereafter, they are drawn into a straight continuous thread. This process is called cerding. The kind of yarns that are produced may be woollen yarn or worsted yarn.

For the production oi wooiien yarn, the web is split into fine thin strands, by a process called roving. It is then spun into woollen yarn. Woollen fabric such as tweed is woven from woollen yarn. It is a bulky fabric in which short woollen fibres are arranged randomly. It does not have smooth surface.

For the production of worsted yam, the web is processed by the machines that (i) straighten the fibres (ii) make them parallel (iii) remove all the short fibres. The resultant woolen strand is then condensed by passing it through several machines, until a very thin strand of worsted roving is obtained. It is then spun to a smooth yarn.

Question 4.
What are the uses of wool? What is woolmark?
Answer:
Wool is used for making fabrics, shawls, blankets, carpets, felt (compressed wool) and upholstery. Wool felt is used to cover piano hammers. It is also used to absorb noise in heavy machinery and stereo speakers.

Shoddy is made from the used wool. To make shoddy, the existing wool fabric is cut into small pieces and then carddd. The carded wool is then respun into yarn. Such a yarn is inferior to the fresh wool and is used for making cheap woollen garments and blankets.

Woolmark:
Wool is marketed worldwide by the International Wool Secretariat (IWS), which is based in Ilkley, North Yorkshise (U.K.). The “Woolmark” instituted by IWS indicates that garments bearing this sign are made from pure new wool, that has not been used previously in any process.

Fibre to Fabric Class 7  HBSE Notes

• Wool comes from sheep, goat, yak and some other animals. These wool- yielding animals bear hair (fleece) on their body.
• The hairy skin of the sheep has two types of fibres that form its fleece : (i) the coarse beard hair, and (ii) the fine soft under hair close to the skin.
• The wool which is used for knitting sweaters or for weaving shawls is the finished product of a long process.
• Sheep hair is sheared off from the body, scoured, sorted, dried, dyed, spun and woven to yield wool.
• The hairs of camel, llama and alpaca are also processed to yield wool.
• The wool may be classified as Virgin, Hogg or pulled depending upon its quality.
• In wool production, Australia and New Zealand produce two-thirds of the world’s supply.
• Woolmark is the mark of standardisation given to pure and new wool.
• Silk fibres are also animal fibres. Silkworms spin the ‘silk fibres’. The rearing of silkworms for obtaining silk is called sericulture.
• The female silk moth lays eggs, from which hatch larvae which are called caterpillars or silkworms.
• During their life cycle, the worms spin cocoons of silk fibres.
• Silk fibres are made of a protein.
• Tassar silk, mooga silk, kosa silk, etc., are obtained from cocoons spun by different types of moths.
• The most common silk moth is the mulberry silk moth. The silk fibre from the cocoon of this moth is soft, lustrous and elastic and can be dyed in beautiful colours.
• Sericulture is a very old occupation in India. India produces plenty of silk on a commercial scale.
• A pile of cocoons is used for obtaining silk fibres. This process is called reeling of silk. The cocoons are kept under the sun or boiled or exposed to steam. The silk fibres separate out. The process of taking out threads from the cocoon for use as silk is called reeling the silk.

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 18 Wastewater Story Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 18 Wastewater Story

HBSE 7th Class Science Wastewater Story Textbook Questions and Answers

Question 1.
Fill in the blanks :
(a) Cleaning of water is a process of removing _________.
(b) Wastewater released by houses is called _________.
(c) Dried _________ is used as manure.
(d) Drains get blocked by _________ and _________.
Answer:
(a) pollutants
(b) sewage
(c) sludge
(d) chemicals, kitchenwaste.

Question 2.
What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
Answer:
Sewage is a liquid containing wastes disposed off by household, industrial and agricultural, activities in water. It is dangerous to release untreated sewage in water because it can pollute the whole source of water. Sewage contain harmful substances and disease causing organisms. It is therefore, dangerous and unsafe to release untreated sewage in water.

Question 3.
Why should oils and fats be not realeased in the drain? Explain.
Answer:
Oils and fats should not be released in, the drains because they harden the soil in the pipes and block them. Fats get clogged in the holes of the soil in the drain and block it. It does not allow the wastewater to flow and thus the whole sewer system is blocked.

Question 4.
Describe the steps involved in getting clarified water from wastewater.
Answer:
Water is treated physically, chemically and biologically in wastewater treatment plant.
Following Steps are involved in the purification of water:
(i) At first stage all the physical impurities like stones, rags, napkins, plastic bags, cans, packets etc. are removed. It is done by passing the water through bar screens.

(ii) Then water is taken to grit and sand removal tank where impurities are removed by sedimentation.

(iii) Solids impurities and faeces etc. are collected from the bottom of the water. These solid impurities collected are called sludge. Water is cleared of floatable solids like oil and grease.

(iv) Clarified water is cleared of other impurities by aerator. All disease causing bacteria are removed by chlorination and water is released in various water bodies.

Question 5.
What is sludge? Explain how it is treated.
Answer:
Sludge is the collected solid waste from the wastewater during the treatment in water treatment plant. Sludge is decomposed in a separate tank by the anaerobic bacteria. Activated sludge is used as manure.

Question 6.
Untreated human excreta is a health hazard. Explain.
Answer:
Untreated excreta can cause a lot of health related problems. It pollutes soil, water and air. The polluted water contain disease causing bacteria, which can spread epidemics like cholera, meningities etc.

Question 7.
Name two chemicals used to disinfect water.
Answer:
Chlorine and ozone are the chemical used to clean the wastewater.

Question 8.
Explain the function of bar screens in a wastewater treatment plant.
Answer:
Bar screens clear the wastewater of all the physical impurities. Large waste objects like napkins, plastics, can sticks, rags etc. are, removed from the wastewater through the bar screens.

Question 9.
Explain the relationship between sanitation and disease.
Answer:
Sanitation and disease are related each other. It sanitation is there no disease will occur, but if the sanitation is not there various types of diseases will occur and spread. So sanitation should be kept to avoid diseases.

Question 10.
Outline your role as an active citizen in relation to sanitation.
Answer:
As active citizen we should take care of our personal and environmental sanitation. We should make people around us, aware of the benefits of sanitation we should help the municipal corporations and gram panchayats to cover all the open drains and remove the unhygenic and disease causing substances thrown in’open.

Question 11
Here is a crossword puzzle : “Good luck !

Across:
3. Liquid waste products
4. Solid waste extracted in sewage treatment
6. A word related to hygiene
8. Waste matter discharged from human body

Down:
1. Used water
2. A pipe carrying sewage
5. Micro-organisms which causes cholera
7. A chemical to disinfect water
Answer:

Question 12.
Study the following statements about ozone:
(a) It is essential for breathing of living organisms.
(b) It is used to disinfect water.
(c) It absorbs ultraviolet rays.
(d) Its- proportion in air is about 3%.
Which of these statements are correct?
(i) (a), (b) and (c)
(ii) (b) and (c)
(iii) (a) and (d)
(iv) All four
Answer:
(b) and (c)

Extended Learning – Activities and projects

Question 1.
Construct a crossword puzzle of your own using the keywords.
Answer:
Do it yourself.

Question 2.
Then and now; Talk to your grand parents and other elderly people in the neighbourhood. Find out the sewage disposal systems available to them. You can also write letters to people living in far off places to get more information. Prepare a brief-report, on the information you collected.
Answer:
Do it yourself.

Question 3.
Visit a sewage treatment,plant.
It-could be as exciting and enriching as a visit to a zoo, a museum, or a park. To guide your observation here are a few suggestions.
Record in your notepad :
Place _________ Date _________ Time Name of the official at the plant _________ Guide/Teacher _________.
(a) The location of the sewage plant.
(b) Treatment capacity.
(c) The purpose of screening as the initial process.
(d) How is air bubbled through the aeration tank?
(e) How safe is the water at the end of the treatment? How is it tested?
(f) Where is the water discharged after treatment?
(g) What happens to the plant during heavy rains?
(h) Is biogas consumed within the plant or sold to other consumers?
(i) What happens to the treatment sludge?
(j) Is there any special effort to protect nearby houses from the plant?
(k) Other observations.
Answer:
Do it yourself.

HBSE 7th Class Science Wastewater Story Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Write different sources of wastewater?
Answer:
Household activities, industrial activities and agricultural activities.

Question 2.
Name certain organic impurities in the wastewater.
Answer:
Animal waste, Human faeces, oil and urine, fruits and vegetables.

Question 3.
Write certain Inorganic impurities in, the wastewater.
Answer:
Metals, phosphates and nitrates.

Question 4.
Name certain disease causing micro-organism.
Answer:
Bacterias, Viruses etc.

Question 5.
Which process removes the solids like faeces and other substances from the wastewater?
Answer:
Grit and sand removal tank.

Question 6.
Which instrument is used to remove floatable solids from the wastewater?
Answer:
A skimmer is used to remove floatable impurities.

Question 7.
Who decomposes the sludge?
Answer:
Anaerobic bacteria decompose the sludge.

Question 8.
What helps to clean the clarified water?
Answer:
Aerobic bacteria helps to clean the clarified water.

Question 9.
Why is ozone and chlorine used?
Answer:
Ozone and Chlorine is used to kill the bacteria etc. present in the clarified water.

Short Answer Type Questions

Question 1.
How is water’polluted?
Answer:
Water is used for various’purposes in homes, industries and agriculture. When water is used for cleaning, bathing, washing, dying etc. it pollutes the water. Unwanted waste materials and chemicals etc. get added in the water and this wastes the water.

Question 2.
How “bar screen” and ‘grit and sand removal tank’ help in clarification of water?
Answer:
When wastewater is passed through bar screens it separates big and large objects like plastics, bags, sticks, can, napkins etc. In grit and sand removal tank other solid impurities like pebbless and etc. are removed.

Question 3.
How is sludge treated?
Answer:
Sludge is the solid impurities separated from the sewage. It is removed and treated in a separate tank with anaerobic bacteria. During this process biogas is produced which is used to produce electricity. Dried sludge is used as manure.

Question 4.
What are the problem arising due to open drains and other unsanitary conditions?
Answer:
Open drains and unsanitary conditions produce bad smell. It becomes an idle place of breeding for mosquitoes, files and other harmful insects. These insects spread many harmful diseases and other health hazards.

Question 5.
How the kitchen waste blocks the drains?
Answer:
Kitchen waste like oils and fats clogs the pores in soil and reduce the Alteration process. It also blocks the pipes by hardening the pipes. Wastes like tealeaves solid food remains, cotton etc. also choke the pipes and slows down flow of oxygen. This slows down the decomposition process by the aerobic bacteria.

Long Answer Type Questions

Question 1.
How defection in open cause health hazards?
Answer:
Due to lack of proper sewage disposal system a large amount of people in India defecates in open. They use riverbeds, railway lines, fields and drains for this purpose. These excreta dries down and percolate, in soil with rain water. It pollutes the ground water. Excreate along river bed pollutes the river water. In this way water on the ground and under the ground get polluted. This polluted water contains the micro-organisms of various communicable diseases like cholera, typhoid, hepatilis and meningiti it is dysentry etc.

Wastewater Story Class 7 HBSE Notes

• Water is a precious natural resource.
• We cannot imagine our lives without water.
• We waste a lot of water daily in various household and industrial activities Such water is called wastewater.
• The wastewater produced during household activities, industrial activities, and various agricultural processes is also called sewage.
• Sewage is the liquid waste that can cause various diseases and environmental hazards if not managed.
• Sewage is collected from its sources and treated to destroy its harmful constituent to clean it.
• It is made usable in treatment plants and disposed of in various sources of water.
• Drainage systems should be covered to avoid communicable diseases.
• We should not throw waste in the open and should not defecate in open.
• Low-cost disposal methods can be adopted in areas where a proper sewer system is not available.

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 Board HBSE 7th Class Science Solutions

HBSE 7th Class Science Solutions in English Medium

• Chapter 1 Nutrition in Plants
• Chapter 2 Nutrition in Animals
• Chapter 3 Fibre to Fabric
• Chapter 4 Heat
• Chapter 5 Acids, Bases and Salts
• Chapter 6 Physical and Chemical Changes
• Chapter 7 Weather, Climate and Adaptations of Animals to Climate
• Chapter 8 Winds, Storms and Cyclones
• Chapter 9 Soil
• Chapter 10 Respiration in Organisms
• Chapter 11 Transportation in Animals and Plants
• Chapter 12 Reproduction in Plants
• Chapter 13 Motion and Time
• Chapter 14 Electric Current and its Effects
• Chapter 15 Light
• Chapter 16 Water: A Precious Resource
• Chapter 17 Forests: Our Lifeline
• Chapter 18 Wastewater Story

HBSE 7th Class Science Solutions in Hindi Medium

• Chapter 1 पादपों में पोषण
• Chapter 2 प्राणियों में पोषण
• Chapter 3 रेशों से वस्त्र तकग
• Chapter 4 ऊष्मा
• Chapter 5 अम्ल, क्षारक और लवण
• Chapter 6 भौतिक एवं रासायनिक परिवर्तन
• Chapter 7 मौसम, जलवायु तथा जलवायु के अनुरूप जंतुओं द्वारा अनुकूल
• Chapter 8 पवन, तूफ़ान और चक्रवात
• Chapter 9 मृदा
• Chapter 10 जीवों में श्वसन
• Chapter 11 जंतुओं और पादप में परिवहन
• Chapter 12 पादप में जनन
• Chapter 13 गति एवं समय
• Chapter 14 विद्युत धारा और इसके प्रभाव
• Chapter 15 प्रकाश
• Chapter 16 जल: एक बहुमूल्य संसाधन
• Chapter 17 वन: हमारी जीवन रेखा
• Chapter 18 अपशिष्ट जल की कहानी

Haryana State Board HBSE 7th Class Social Science Solutions Civics Chapter 9 A Shirt in the Market Textbook Exercise Questions and Answers.

Haryana Board 7th Class Social Science Solutions Civics Chapter 9 A Shirt in the Market

HBSE 7th Class Civics A Shirt in the Market Textbook Questions and Answers

Question 1.
What made Swapna sell the cotton to the trader instead of selling it at the Kurnool cloth market?
Answer:
The following reason made Swapna sell the cotton to the traders instead of selling at the Kurnool cloth market.

Swapna had borrowed ₹ 2,500 from the trader at a very high rate of interest to buy seeds, fertilizers, and pesticides for cultivation. At this time the trader enters an agreement with Swapna that she will sell her cotton to him. So, Swapna sells her cotton to traded instead of selling in Kurnool cloth market.

Question 2.
Describe the condition of employment as well as the wages of the workers in garment exporting factory* Do you think that the workers get a fair deal?
Answer:
(i) The workers in the garment exporting factory work at least 10 to 12 hrs. in a day but they get very low wages monthly.
(ii) Their job is not permanent; whenever the employer feels that a worker is not needed, he may be asked to leave.
(iii) Their wages are fixed according to their skills.
(iv) The highest paid among the workers are the tailors, who get maximum salary of 3,000 per month.
(v) More women are employee in these factories as helpers.
(vi) These jobs fetch him very low salary.
Now, these workers do not get fair deal.

Question 3.
Think of something common that we use. It could be sugar, tea, milk, pen, paper etc. Discuss through what chain of markets this reacts to you. Can you think of the people that help in the production or trade?
Answer:
A chain of markets links the producer to the buyer. Buying and selling takes place at every step in the chain.
Through Retailer: The producer supplies goods to retailer who sells them to the consumers:

Producers
|
Retailer
|
Customer (Buyer)

Through Wholesaler: The producer may supply goods to wholesaler in large quantity who can further sell the same in small quantities to the customers. There is no place of retailer in it.

Produce
|
Wholesaler
|
Customers

Through agent, wholesaler and retailer: The producer may also involve the agent (intermediator) in this chain of marketing.

Producer
|
Agents
|
Wholesaler
|
Customer

People from a simple worker to the main producer, agents, wholesaler, retailer all help in the production or trade.

Question 4.
Arrange the statements given below in the correct order and then fill the number in the cotton balls accordingly. The first two have been solved for you.
1. Swapna sells the cloth to the trader.
2. Customers buy these shirts in the supermarket.
3. Trader sells cotton to the ginning mill.
4. Garment exporters buy the cloth from merchants for making shirts.
5. Yarn dealers or merchants give the yarn to the weavers.
6. The exporter sells shirts to the business persons from the USA.
7. Spinning mill buys the cotton and sells yarn to the yarn dealers.
8. Weavers return with the cloth.
9. Ginning mill cleans the cotton and makes it into balls.

Answer:
1. Swapna sells the cloth to the trader.
2. Trader sells cotton to the ginning mill.
3. Ginning mill cleans the cotton and makes it into balls.
4. Spinning mill buys the cotton and sells yarn to the yarn dealers.
5. Yarn dealers or merchants give the yarn to the weavers.
6. Weavers return with the cloth.
7. Garment exporters buy the cloth from merchants for making shirts.
8. The exporter sells shirts to the business persons from the USA.
9. Customers buy these shirts in the supermarket.

Question 5.
Did Swapna get a fair price on the cotton?
Answer:
No, Swapna did not get a fair price on the cotton.

Question 6.
Why did the trader pay Swapna a low price?
Answer:
The trader paid Swapna a low price because she had borrowed ₹ 2500 at the time of cropping season at high rate of interest.

Question 7.
Where db you think larger farm would sell cotton? How is their situation better than Swapna?
Answer:
Larger farmer would prefer to sell their product in wholesale market. Their situation is better from Swapna because Swapna cannot sell the product in wholesale market. She has to sell it through trader and she does not get price for her product.

Question 8.
You might have co-operatives in your areas. It could be in a milk provision, paddy etc. Find out for whose benefits they were set up.
Answer:
These co-operatives have been set up for the benefit of the local people of the area especially for the poor farmers.

Question 9.
What are the following people doing at the Erode cloth market-merchants, weavers, exporters?
Answer:
Merchants: Merchants are getting the woven cloth from the weavers after paying them wages for weaving cloth them from.
Weavers: The weavers spend long hours working on looms and they work for wages.
Exporters: Exporters arrange the cloth for exports.

Question 10.
In what ways are weavers dependent on cloth merchants?
Answer:
Weavers are dependent on cloth merchants because:
The cloth merchants give them thread and they weave cloth for them from where they earn their living.

Question 11.
Why do you think more women are employed in the Impex garment factory? Discuss.
Answer:
More women are employed in the Impex garments factory because:
(a) They do the work of thread cutting, buttoning, ironing and packaging more patiently.
(b) These jobs have the lowest wages and women are ready to work for the lowest wages.
(c) They do not raise disputes.

Question 12.
The shirt shows the profit made by the business person, and the various costs that he had to pay. Find out from the diagram below, what cost price includes.

Answer:
The cost price includes:
Purchase (₹ 200) + Storage 100) + advertising (₹ 300)
= ₹ 600.

Question 13.
What are the demands of foreign buyers made on the garment export? Why do the garment exporters agree to these demands?
Answer:
The foreign buyer demands the following from the supplier:
(a) the lowest prices
(b) high standards of equality
(c) prompt delivery of goods
The garment exporter agrees to fulfill the demand of foreign buyers because he hopes to get a bulk order.

Question 14.
What are the reasons that the business person is able to make a huge profit in the market?
Answer:
The business person is able to make huge profit in the market because:
(a) He sells his shirts to high income people who do not ask for the prices.
(b) He tries to meet the latest demands of the customers.

HBSE 7th Class Civics A Shirt in the Market Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Who is Swapna and what does she do?
Answer:
Swapna is a small farmer in Kurnool and she grows cotton.

Question 2.
What is putting out system?
Answer:
The arrangement between the merchant and the weavers is known as putting out system.

Question 3.
To whom does the Erode merchant supply the cotton cloth?
Answer:
The Erode merchant supplies the cotton cloth to a garment exporting factory near Delhi.

Short Answer Type Questions

Question 1.
Write about Erode’s cloth market in brief.
Answer:
Erode is a bi-weekly cloth market in Tamil Nadu. It is one of the largest cloth markets in the world. A large variety of clothes are sold in this market.

Question 2.
What is the role of merchant in making the clothes?
Answer:
The merchant distributes work among the weavers based on the orders he has received for cloth. For this, he buys the yarn and gives to the weavers with instructions about the kind of cloth that is to be made.

Question 3.
What is the role of market in the lives of people related to cloth?
Answer:
The market offers people, related to cloth, opportunities for work and to be able to sell things that they grow or produce. It could be the farmer selling cotton or weaver producing cloth.

Question 4.
Why have the poor people to depend on rich persons?
Answer:
The poor have people to depend on the rich and the powerful persons for loans, raw materials and marketing of their goods, and most often for employment.

Long Answer Type Questions

Question 1.
How do the weaver’s cooperatives work? How are they helpful for the weavers?
Answer:
In weavers’ cooperative:
(a) The weavers form a group and take up certain activities collectively.
(b) They procure yarn from the yarn dealer and distribute it among the weavers.
(c) The co-operative also does the marketing.

They are helpful for the weavers because:
(i) the role of merchant is reduced and weavers get a fair price on the cloth.
(ii) The government also helps the cooperatives by buying cloth from them at a reasonable price.

Question 2.
Write a note on the Impex garment factory.
Answer:

• The Impex garment factory has 70 workers.
• Most of them are women. Most of these workers are employed on a temporary basis.
• The employer can remove the workers when he does not need them.
• Workers wages are fixed according to their skills.
• The highest paid among workers are the tailors who get about ₹ 3,000 per month.
• Women are employed at the lowest paid wages for the jobs like thread cutting, buttoning, ironing and packaging.

A Shirt in the Market Class 7 HBSE Notes

• Ginning Mill: A factory where seeds are removed from cotton balls. The cotton is pressed into bales to be sent for spinning into thread.
• Exporter: A person who sells goods abroad.
• Profit: The amount that is left or gained from earnings after deducting all the costs. If the costs are more than the earnings, it would lead to a loss.