Author name: Bhagya

Haryana State Board HBSE 6th Class English Solutions A Pact with the Sun Chapter 4 The Old-Clock Shop Textbook Exercise Questions and Answers.

Haryana Board 6th Class English Solutions A Pact with the Sun Chapter 4 The Old-Clock Shop

HBSE 6th Class English The Old-Clock Shop Textbook Questions and Answers

Question 1.
What made Ray think the visitor was not really a shopper?
Answer:
The visitor was a man closer to fifty. He approached the counter without any sign of friendliness in his eyes. Moreover, he had a gun and a restless hand in the coat pocket. It made Ray think that the visitor was not really a shopper.

Question 2.
Why do you think he had come to the shop?
Answer:
The older man was in need of money. He was down on his luck. He had come there to get some loan by pawning his wristwatch.

Question 3.
How did Ray communicate with him?
Answer:
Ray was deaf. He pushed a notepad and a pencil across the counter. He wrote on the notepad, “May I help you?” The man wrote back, “How much will you give me for this (wrist watch)?” In this way, Ray communicated with him through the notepad.

Question 4.
What do you think the man said to his friend who waited at the door?
Answer:
The older man’s friend was waiting at the door. Both of them were down on their luck. They were ready to try something they would feel sorry about in future. (Perhaps they had come to loot the shop-owner on gun-point). I think, the older man asked his friend not to cause any harm to the shop-keeper.

Question 5.
Ray was not a pawnbroker. Why then did he lend money to people in exchange for their old watches and clocks?
Answer:
No doubt, Ray was not a pawnbroker but he was kind-hearted. He realized the need for poor people. He could not say ‘No to the needy people who placed their old watches or clocks before him.

Question 6.
‘The watch was nothing special and yet had great powers.” In what sense did it have ‘great power’?
Answer:
The watch was something to exchange as a way out of a bad situation. The man was down on his luck. He would exchange his watch for something which would bring good luck for him. Therefore, the non-special watch had great powers.

Question 7.
Do you think the man would ever come back to pick up the watch?
Answer:
Ray paid a fifty-dollar note to the older man as a loan against the watch. The watch wasn’t worth that much. The over-payment is an indication that the man would never come back to pick up the watch. There is another indication that the watch had great powers. It would change the old man’s condition. Therefore, he would come back to pick it up as soon as he can.

Question 8.
When did the unfriendly face of the visitor turn truly friendly?
Answer:
The older man approached the counter with an unfriendly face. Ray felt afraid but smiled at the unfriendly face. He also pointed to his ears and shook his head from side to side. The older man got surprised when he studied the note pad. (He learnt that ray was deaf). Ray’s words”May I help you?” turned the unfriendly face of the visitor into truly friendly.

The Old-Clock Shop Word Meanings

arrived – approached = आ पहुँची थी, shoppers customers = ग्राहक, thick – compact = मोटी, yeteven then = फिर भी, deaf – one who cannot hear = बहरा, rush- gust = झोंका, hit – struck = प्रहार किया, twenties – aged between twenty and twenty nine = बीस से उन्नतीस वर्ष की आयु के बीच। closer nearer = समीप। remained – stayed = ठहरा रहा, approached – came near = पास आया। sign – clue = संकेत। growing – increasing by degrees = बढती हुई। slowly – at an easy pace = मंद गति से। Notepad – a pad to write notes = कागजों की गद्दी (गड्डी), unfriendly – hostile = शत्रुतापूर्ण, pointed – showed the direction of = संकेत करना, shook – moved = हिलाया। surprise – wonder = आश्चर्य, studied – read = पढ़ा, chance – occasion = अवसर, closely – from a quite near distance = बहुत नजदीक से, shape form = शक्ल, restless – uneasy = अशांत, still – calm = शांत, directly – straight = सीधे। macking of ridicule = उपहास वाली, looked – seemed = दिखाई पड़ना। luck – fortune = भाग्य, later – afterwards = बाद में, ticked on – produced sound like a clock = घड़ी की तरह टिक-टिक की आवाज करना, message – what one wants to say = संदेश, Pick up – to take = लेना, चुनना, loan – (debt) credit = ऋण, Pawnbroker – one who lends money on some security = गिरवी रखने वाला, needy – one who wants something = जरूरतमंद, placed = kept = रखना, loaned – gave on credit. = ऋण देना, interest money paid for use of something = ब्याज, easier – cooler = शांत, Wrist – the front part of the hand = कलाई, Noticed – observed = निहारा, grey – brownish = भूरी, special – peculiar = विशेष, Exchange = to change a thing with another thing = विनिमय, way out – solution = रास्ता, situation – condition = हालत, need – urgency = जरूरत। need – (here) require, = चाहते हो, worth having value = काबिल, कीमत के योग्य, reached into – put hand inside = अन्दर हाथ डाला, pulled out – brought out = बाहर निकाला, seemed – appeared = दिखाई पड़ना, turning – to take a turn = मुड़ना, merry – happy = शुभ, Together – jointly = एक साथ, all the while – all the time = सारा समय।

The Old-Clock Shop Summary in English

It was a snowy Christmas evening. Ray was working on a clock in his old clock shop. He stood up after finishing his work. Just then he saw two men. One was in his twenties. The other was closer to fifty. They did not look like customers. The younger man stayed at the door. The older man approached the counter. Ray felt afraid and pointed to his deaf ears. He wrote on the notepad, “May I help you?” The old man was down on his luck.

Ray understood that the older man was needy. He had something like a gun in his pocket. He showed his wristwatch to Ray. The watch seemed to have great powers. Ray offered a fifty-dollar note him. He had loaned more than he should. The older man thanked Ray. He wished him Merry Christmas’. He also promised that he would pick up his watch as soon as he could.

The Old-Clock Shop Summary in Hindi

क्रिसमस की एक बर्फीली शाम थी। घड़ियों की अपनी पुरानी दुकान में रे एक घड़ी की मरम्मत कर रहा था। अपना काम समाप्त करके वह खड़ा हो गया। तभी उसे दो आदमी दिखाई दिए। एक की आयु बीस वर्ष से अधिक थी। दूसरे की आयु पचास वर्ष के करीब थी। वे ग्राहकों जैसे दिखाई नहीं पड़ते थे। छोटी आयु वाला व्यक्ति दरवाजे के पास ठहरा रहा। बड़ी आयु वाला व्यक्ति काऊंटर के पास पहुँचा। रे को भय लगा और उसने अपने बहरे कानों की तरफ इशारा किया। उसने नोटपैड के ऊपर लिखा, “क्या मैं आपकी मदद कर सकता हूँ।” बड़ी आयु वाला व्यक्ति भाग्य का मारा हुआ था।

रे समझ गया कि बड़ी आयु वाला व्यक्ति जरूरतमंद है। उसकी जेब में बंदूक जैसी कोई चीज थी। उसने रे को अपनी कलाई घड़ी दिखाई। ऐसा लगता था कि घड़ी में महान शक्तियां थीं। रे ने पचास-डालर वाला एक नोट उसे दिया। उसे जितना ऋण देना चाहिए था उससे अधिक ऋण दे दिया था। बड़ी आयु वाले व्यक्ति ने रे का धन्यवाद किया। उसने रे को क्रिमसम की शुभकामना दी। उसने यह भी वचन दिया कि वह बहुत जल्दी ही अपनी घड़ी वापस लेने आएगा।

Haryana State Board HBSE 6th Class English Solutions A Pact with the Sun Chapter 3 The Shepherds Treasure Textbook Exercise Questions and Answers.

Haryana Board 6th Class English Solutions A Pact with the Sun Chapter 3 The Shepherds Treasure

HBSE 6th Class English The Shepherds Treasure Textbook Questions and Answers

Question 1.
The shepherd hadn’t been to school because :
(i) he was very poor.
(ii) there were very few schools in those days.
(iii) he wasn’t interested in studies.
Choose the right answer.
Answer:
(ii) There were very few schools in those days.

Question 2.
Who visited the shepherd one day, and why ?
Answer:
The king of the country visited him one day. He wanted to meet him and find out the truth.

Question 3.
Why did the other governors x grow jealous of the shepherd ?
Answer:
The other governors grew jealous of the shepherd because he grew very famous as a fair and wise governor of the country.

Question 4.
Why was the new governor called to the palace ?
Answer:
The new governor was called to the palace because the king wanted to know the secret of the iron chest.

Question 5.
Why was everyone delighted to see the iron chest on the camel’s back ?
Answer:
Everyone was delighted to see the iron chest on the camel’s back because they thought that this would prove beyond doubt that the charges levelled against the governor were true.

Question 6.
(i) What did the iron chest contain ?
(ii) Why did the shepherd always carry it ?
(iii) Is it an example of the shepherd’s humility or wisdom or both ?
Answer:
(i) The iron chest contained an old blanket.
(ii) The shepherd always carried it because he regarded it as his best friend. This blanket could protect him if the king took away new clothes.
(iii) It was an example of the shepherd’s humility as well as wisdom.

Question 7.
How did the king reward the new governor ?
Answer:
The king rewarded him by making him the governor of a much bigger district that very day.

HBSE 6th Class English The Shepherds Treasure Important Questions and Answers

Question 1.
How did the poor shepherd become famous ?
Answer:
The shepherd though poor, was very wise. He could understand people’s sorrows and troubles. He helped them to face them wisely with courage. Thus he became famous for his wise and friendly nature.

Question 2.
Why did the king disguise himself as a shepherd ?
Answer:
The king wanted to test the shepherd’s wisdom and friendliness so he disguised himself as a shepherd and came to the cave. He did not want to disclose his identity to the shepherd.

Question 3.
How did the shepherd welcome the king who come to him as a poor traveller ?
Answer:
The shepherd welcomed the traveller. He served him water and a share of his own simple meal.

Question 4.
Why did the old governors of the kingdom talk against, the new governor ?
Answer:
As the new governor was humble and wise, he soon became very famous. The old governors became very jeolous so they talked against the new governor.

Question 5.
What is the moral of the story ?
Answer:
The moral of the story is that humility and wisdom always pay in the long run.

The Shepherds Treasure Word Meanings

shepherd (शेफड) = गड़रिया, cottage (कॉटेज) = झोंपड़ी, uneducated (अनएज्यूकेटेड) = अशिक्षित, wise (वाइज) = बुद्धिमान, sorrows (सोरोज) = दु:ख, troubles (ट्रब्लस) = परेशानियाँadvice (एडवाइस) = सलाह, famous (फेमस)प्रसिद्ध, wisdom (विजडम) = बुद्धिमानी, country (कन्ट्री)देश, meeting (मीटिंग) = मिलना, disguised (डिसगाईज्ड)छद्म वेश में, mule (म्यूल) = खच्चर, cave (केव)- गुफा, meagre (मीगर) = अपर्याप्त, greatly (ग्रेटली) = काफी ज्यादा, impressed (इम्प्रेस्ड) = प्रभावित, hospitality (हास्पेटिलिटी) = मेजबानी, अतिथि सत्कार, conversation (कन्वर्शन) = बातचीत, depart (डिपार्ट) = विदा होना, kindness (काइन्डनेस) = दया, permit (परमिट) = आज्ञा देना, leave (लीव) = छुट्टी, छोड़ना, guest (गेस्ट) = मेहमान, majesty (मेजेस्टी)- हुजूर, compliment (कम्पलीमेन्ट) = आदर-सत्कार, astonished (एस्टोनिस्ड) = आश्चर्यचकित indeed (इन्डीड) = वास्तव में, appointed (अपायन्टेड) = नियुक्त किया, humble (हम्बल) = विनम्र, governor (गवर्नर) = राज्यपाल, district (डिस्ट्रीक्ट) = जिला, dignity (डिगनिटी) = सम्मान, sympathy (सेम्पैथी) = सद्भावना, सहानुभूति, goodness (गुडनेस) = अच्छापन, just (जस्ट) = न्यायप्रिय, throughout(धू-आउट) = सारी जगह, provinces (प्रोविन्सेज)- प्रान्त, terribly (टेरिबली) = भयंकर रूप से। jealous (जेलयस) ईर्ष्यालु, dishonest (डिसओनस्ट) = बेईमान, collect (कलैक्ट) = इकट्ठा करता है, added (एडेड) कहा (यहाँ), iron chest (आयरनचेस्ट) = लोहे की पेटी (यहाँ) treasure (ट्रेजर) = खजाना, secretly (सिक्रेटली) = गुप्त रूप से, attention (अटेन्शन) = ध्यान, ignore (इग्नोर) = नजर अन्दाज करना, endless (एन्डलस) = अंतहीन, summoned (सम्मनअड) = बुलाया, palace (पैलेस) = महल, camel (कमल) ऊँट, delight (डिलाइट) खुशी, fastened (फास्टअनड) = बाँध ना, securely (सिक्योरअली)- सुरक्षित ढंग से, contain (कन्टेन) = रखता है, smiled (स्माइल्ड) = मुस्कराया, eagerly (इगअरली) = उत्सुकता से, astonishment (एस्टचोनिशमेन्ट) = आश्चर्य में, gold (गोल्ड) = सोना, silver (सिल्वर) = चाँदी, blanket (ब्लेन्कट) कम्बल, holding (होल्डिंग) = पकड़े हुए, proudly (प्राउडलि)- घमंड से, treasure (ट्रेजर)- खजाना, dignity (डिगनिटी) = सम्मान, take away (टेकअवे) = ले लेना, cloaks (क्लोक्स)- कपड़े, embarrassed (एम्ब्रेअसड) = परेशान, jealous (जेलस) = ईर्ष्यालु, wisest (वाइजेस्ट) = सबसे ज्यादा बुद्धिमान।

The Shepherds Treasure Summary in English

Once there lived a shepherd who was uneducated but very wise and helpful. He was very famous for his wisdom. Once the king went to meet him disguised as a shepherd on a mule. He behaved and greeted him very nicely. This poor shepherd could make out that his visitor was the king of his kingdom. The king was impressed with his wisdom. He made him the governor of a small district. Other governors grew jealous of this shepherd and hatched a conspiracy. The king frequently complained of the shepherd’s dishonesty as a new governor. One day he was summoned to the palace. Then he was asked to explain why he always carried an iron chest with him. When the iron chest was opened, it was not found to contain any treasures as his enemies had been alleging. It contained an old blanket which the shepherd regarded as his oldest friend.

The Shepherds Treasure Summary in Hindi

एक बार एक गडरिया जो कि अशिक्षित परन्तु बुद्धिमान और सहायता करने वाला रहता था। वह अपनी बुद्धिमता के लिए बहुत प्रसिद्ध था। एक बार राजा एक खच्चर पर बैठकर गडरिये के रूप में वेश बदलकर उससे मिलने गया। उसने (गड़रिये ने) अच्छी तरह से स्वागत-सत्कार तथा व्यवहार किया। यह गरीब गडरिया समझ गया था कि उसका दर्शक राज्य का राजा था। राजा उसकी बुद्धिमता से बहुत प्रभावित हुआ। राजा ने उसे छोटे से जिले का राज्यपाल बना दिया। अन्य राज्यपाल इस गड़रिये से बहुत ईर्ष्यालु हो गए और उन्होंने एक षड्यंत्र रचा। राजा को नये राज्यपाल अर्थात् गड़रिये की बेईमानी के बारे में बार-बार शिकायतें की जाती थी। एक दिन नये राज्यपाल (गड़रिया) को महल बुला लिया गया। वहाँ उससे अपने साथ हमेशा लोहे की पेटी रखने का कारण पूछा गया। जब लोहे की पेटी खोली गई तो जैसा कि उसके दुश्मन आरोप लगा रहे थे ऐसा कोई खजाना नहीं पाया गया। इसमें एक पुरानी कम्बल थी जिसे गड़रिया अपना सबसे पुराना मित्र मानता था।

Haryana State Board HBSE 6th Class English Solutions A Pact with the Sun Chapter 2 The Friendly Mongoose Textbook Exercise Questions and Answers.

Haryana Board 6th Class English Solutions A Pact with the Sun Chapter 2 The Friendly Mongoose

HBSE 6th Class English The Friendly Mongoose Textbook Questions and Answers

Question 1.
Why did the farmer bring a baby mongoose into the house?
Answer:
The farmer brought a baby mongoose into the house to provide a companion to his son.

Question 2.
Why didn’t the farmer’s wife want to leave the baby alone with the mongoose?
Answer:
The farmer’s wife didn’t want to have the baby alone with the mongoose because she thought the mongoose could harm her son.

Question 3.
What was the farmer’s comment on his wife’s fears?
Answer:
The farmer commented that the mongoose was a friendly animal and that he was the best of his son’s friend.

Question 4.
What did the farmer’s wife strike the mongoose with her basket?
Answer:
The farmer’s wife struck the mongoose with the basket because she thought the mongoose had killed her son.

Question 5.
Did she repent her hasty action? How does she show her repentance?
Answer:
Yes, she repented for her hasty actions as she shed tears later.

Question 6.
Do you have a pet a cat or a dog? If not, would you like one? How would you look after it? Are you for or against keeping birds in a cage as pets?
Answer:
Do it yourself.

HBSE 6th Class English The Friendly Mongoose Important Questions and Answers

Question 1.
Who said this to whom and when? ‘You needn’t be a fraid.’
Answer:
The farmer said this to his wife. He said this when she was going to the market and she told that she did not want her baby to stay alone with the mongoose.

Question 2.
Why did the farmer not return for quite some time?
Answer:
The farmer did not return for quite some time because he met some friends on the way back from fields.

Question 3.
What was customary for the mongoose?
Answer:
It was customary for the mongoose to welcome the farmer’s wife when she returned home.

Question 4.
How did the mongoose prove himself to be a true friend of the baby?
Answer:
When the baby’s parents were not at home the mongoose saw a snake near the baby. He attacked the snake and tore it into pieces. Thus he saved the child. Hence, he proved himself to be a true friend of the baby.

Question 5.
What is the moral of the story?
Answer:
The moral of the story is ‘Don’t act hastily’, and ‘Think twice before you act’.

The Friendly Mongoose Word Meanings

village (विलेज) = गाँव, pet (पेट) = पालतू जानवर, companion (कम्पेनियन) = साथी, tiny (टाइनी) = सूक्ष्म, mongoose (मेन्गूस) = नेवला, fuilly grown (फूलीग्रोन) = पूर्ण विकसित, lovely (लवली) = सुन्दर, रम्य, shining (शाइनी) = चमकदार, bushy (बुशी)- झाड़ीदार, tail (टेल) = पूँछ। Cradle (क्रेडल) = पालना, alternately (आल्टरनेटली) = बारी-बारी से, rocked (रॉक्ड) = हिलाया, basket (बास्केट) टोकरी, friendly (फ्रेन्डली) = मित्रतापूर्ण तरीके से, fields (फिल्डस) = खेत, return (रिटन) = वापसी, finished (फिनिश्ड) = खत्म किया, shooping (शोपिंग) = खरीददारी, groceries (ग्रोसरीज) = घरेलू सामान, welcome (वेलकम) = स्वागत, customary (कास्टमरी) = रिवाज के अनुसार, screamed (स्क्रीम्ड) = चीखी, blood (ब्लड) = खून, paws (पॉज) = पंजे, smeared (स्मीअड) = लेप किया हुआ, सना हुआ, wicked (विकेड) = दुष्ट, screamed (स्क्रीम्ड) = चीखी, hysterically (हिस्ट्रीकली) = उन्मत्त (पागल) जैसा, blind (ब्लाइन्ड) = अंधी, rage (रेग) = नाराज, गुस्सा, strength (स्ट्रेन्थ) = ताकत, askeep (एसलीप) = सोया हुआ, torn (टान) = कटा-फटा होना, bleeding (ब्लीडिंग) = खून बहते हुए, saved (सेव्ड) = बचाया, unaware (अनवेयर) = अनजान था, sobbing (सॉबिंग) = सुबकते हुए, hastily (हेस्टली) = जल्दी से, rashly (रेशली) = लापरवाही से, stared (स्टेयड) = ताका, wiping (वाईपिंग) = पोंडते हुए, tears (टीअर्स) = आँसू, feed (फीड) = पिलाना।

The Friendly Mongoose Summary in English

There lived a farmer, his wife and their small son in a village. The farmer and his wife brought a mongoose to give their son a companion. One day the farmer and his wife had to go out of their house leaving their son alone with the mongoose. When the farmer’s wife returned home, she found the mongoose at the entrance with blood smeared on his face and paws. She thought her son had been killed by the mongoose and as such she killed the mongoose then and there. But when she went to her son, she learnt the truth. In fact the mongoose had guarded her son from the attack of a snake and that’s why her face and paws were smeared with blood. She went to the mongoose and repented a lot. But it was of no use.

The Friendly Mongoose Summary in Hindi

एक गाँव में एक किसान, उसकी पत्नी और उनका छोटा लड़का रहते थे। किसान और उसकी पत्नी एक नेवले को अपने पुत्र को एक साथी की संगति देने के लिए ले आये। एक दिन किसान और उसकी पत्नी को अपने बच्चे को अकेला छोड़कर घर से बाहर जाना पड़ा। जब किसान की पत्नी घर वापस लौटी, उसने नेवले को प्रवेश द्वार पर उसके चेहरे व पंजे को खून से सना हुआ पाया। उसने सोचा नेवले ने उसके पुत्र को मार दिया ऐसा सोचकर उसने भी उस नेवले को मार दिया। लेकन जब वह अपने पुत्र के पास गई तो उसे सच का पता चला। वास्तव में नेवले ने सांप के हमले से उसके लड़के की रक्षा की थी और इसी वजह से उसका चेहरा और पंजे खून से सन गये थे। वह नेवले के पास गई और काफी पश्चात्ताप किया। लेकिन इसका कोई फायदा नहीं था।

Haryana State Board HBSE 8th Class Science Solutions Chapter 10 Reaching the Age of Adolescence Textbook Exercise Questions and Answers.

Haryana Board 8th Class Science Solutions Chapter 10 Reaching the Age of Adolescence

HBSE 8th Class Science Reaching the Age of Adolescence Textbook Questions and Answers

Question 1.
What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer:
Hormones.

Question 2.
Define adolescence.
Answer:
Adolescence: The period of life, when the body undergoes changes, leading to reproductive maturity is called adolescence.

Question 3.
What is menstruation? Explain.
Answer:
When egg produced by ovary does not get fertilized, it along with the thickened lining of the uterus and blood vessels get flown off out of the body every month as bleeding in women. This is called menstruation.

Question 4.
List the changes in the body that take place at puberty.
Answer:
Certain changes take place in the bodies of boys and girls at age of puberty. These include:
(i) Growing of hair at different body parts
(ii) Sudden increase in height.
(iii) Growth of moustaches and beards in boys.
(iv) Voice,of boys get coarsed.
(v) Development of breast in girls and hips get heavy.
(vi) Development of sex organs.

Question 5.
Prepare a table having two columns depicting names of endocrine glands and hormones secreted by them.
Answer:

Question 6.
What are sex hormones? Why are they named so? State their function.
Answer:
Hormones which constitute the secondary sexual characters are called sex hormones. They are called sex hormones because it is because of them that sex is diferentiated i.e. a boy is distinguished from a girl due to these hormones. Their function is to develop the secondary sexual characters in boys and girls.

Question 7.
Choose the correct option:
(a) Adolescents should be careful about what they eat, because ………….
(i) proper diet develops their brains.
(ii) proper diet is needed for the rapid growth taking place in their body.
(iii) adolescents feel hungry all the time.
(iv) taste buds are well developed in teenagers.
Answer:
(ii) proper diet is needed for the rapid growth taking place in their body.

(b) Reproductive age in women starts when their …………..
(i) menstruation starts.
(ii) breasts start developing.
(iii) body weight increases.
(iv) height increases.
Answer:
(i) menstruation starts.

(c) The right meal for adolescents consists of …………
(i) chips, noodles, coke.
(ii) chapati, dal, vegetables.
(iii) rice, noodles and burger.
(iv) vegetable cutlets, chips and lemon drink.
Answer:
(ii) chapati, dal, vegetables.

Question 8.
Write notes on:
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.
Answer:
(a) Adam’s Apple:
Adam’s apple is a protruding part in the throat. It is the enlarged voice box or larynx, which gets enlarged at the onset of puberty. This makes the voice of the boys hoarse.

(b) Secondary Sexual Characters are the characters which distinguish a boy from a girl. Characters like hair on chest, under the arms, development of breast, beard and moustaches etc. are all called secondary sexual characters.

(c) Sex determination in unborn baby: The sex of the unborn baby is determined by the sex chromosomes of the father. An unfertilized
egg always have X chromosome. If a sperm contributes X chromosome then the baby will be a female and if the sperm contributes Y chromosome, the baby will be a male. So it is the father, who is responsible for the sex of the unbomhaby.

Question 9.
Word game: Use the clues to work out the words.
Across
3. Protruding voice box in boys
4. Glands without ducts
7. Endocrine gland attached to brain
8. Secretion of endocrine glands
9. Pancreatic hormone 10. Female hormone

Down
1. Male hormone
2. Secretes thyroxine
3. Another term for Teenage
5. Hormone reaches here through blood stream
6. Voice box
7. Term for changes at adolescence

Answer:

Question 10.
The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?

Answer:
We conclude that girl are taller than boys age of 12 yr. generally and there height is same at the age of 16 years but some boys gain height and generally become taller then girls.

Extended Learning – Activities And Projects

1. Find out from your elder relatives about their awareness of the leagal status of early marriage. You yourself may get information on it from your teacher, parents, a doctor or the internet. Write a two-minute speech explaining why early marriage is not good for the couple.
Answer:
The legal marriagable age for girls is 18 years and for boys it is 21 years. Before this age marriage is considered a crime. Early marriage is not good for couples because they are not prepared physically and mentally for the responsibilities of married life. A girl attains sexual maturity at age of about eighteen years. Before that her resproductive system is not fully prepared to bear a baby. Similarly boys are not capable of running the household as most of the boys at this age are pursuing their studies. So, the boys and girls should attain physical and mental maturity before getting married.

2. Collect newspaper cuttings and information in magazines about HIV/AIDS. Write a one page article of 15 to 20 sentences on HIV/AIDS.
Answer:
HIV/AIDS is a sexually transmitted diseased (STD) that means this diseases mostly spreads by sexual contacts with an HIV/AIDS infected persons. AIDS stands for Acquired Immunodeficiency Syndrome. It is created by HIV virus. This disease is a fatal disease for which no permanent treatement has been deviced by the scientists. AIDS is actually a disease which destroys the patients immune system slowly. The damage is most of the time permanent and beyond repair. Due to weak immunity the patient easily fall prey to many diseases which eventually kill the person.

Prevention is the only cure for HIV/AIDS. It is advised that one should maintain sexual hygiene and practice safe sexual relationship with a single partner.

3. In our country, according to a census, there are 882 adolescent femals for every 1000 males. Find out:
(a) the concerns of the community regarding this low ratio. Remember that the chance of having a boy or a girl is equal.
(b) what amniocentesis is and how useful this technique is. Why, is its use for indentification of sex of the unborn child banned in India l
Answer:
(a) The society is quite concerned about this issue. This is going to create a problem for them in future as it will become difficult for the boys to find girls for marriage.

(b) It is used to see, if all the organs of a feotus are developing well. It is banned in India to use this technique to determine the sex of the unborn child because they kill the female feotus to have baby boys in future. This is called female feoticide. The female feoticide has disturbed the ratio of boys and girls in India.

4. Put your ideas together and write a short note on the importance of knowing facts about reproduction.
For more information , visit:

• www.teenshealth.org/teen/sexual_health/
• www.ama_assn.org/ama/pub/category/ 1947.html
• www.adolescenthealth.com

Answer:
It is important to know facts about reproduction, because this phase i.e. reproduction phase has to come in every bodies life. It will help to handle all the physical and mental changes coming with sexual maturity in the bodies. It will also help in deciding one’s own course of life in future and save for many STDs.

HBSE 8th Class Science Reaching the Age of Adolescence Important Questions and Answers

Very Short Answer Type Questions

Question 1.
What is the phase of life when the body undergoes changes to attain reproductive maturity called?
Answer:
Adolescence.

Question 2.
What is the age period of adolescence?
Answer:
13 years to 18 years.

Question 3.
What is reproductive maturity called?
Answer:
Puberty.

Question 4.
Write any two changes in bodies of boys during adolescence.
Answer:
Increase in height, hairy line above lips.

Question 5.
What makes a person tall during adolescence?
Answer:
Elongated long bones of arms and legs.

Question 6.
What happens to voice box at puberty?
Answer:
It begins to grow.

Question 7.
What is the protruding part of the larynx visible in boy’s throat called?
Answer:
Adam’s Apple.

Question 8.
What changes occur in the voice of boy’s at the onset of puberty?
Answer:
It becomes hoarse.

Question 9.
Why do growing boys and girls get acnes or pimples?
Answer:
Due to increased secretions of sebacious glands.

Question 10.
What are those characters called, which distinguish a boy from a girl?
Answer:
Secondary sexual characters.

Question 11.
Give any one secondary sexual character of boys.
Answer:
Growth of moustaches and beard.

Question 12.
Give any one secondary sexual character of girls.
Answer:
Growth of breasts.

Question 13.
What controls the body changes during adolescence?
Answer:
Hormones.

Question 14.
What are hormones?
Answer:
Hormones are the chemical substances secreted by Endocrine glands.

Question 15.
Name the hormones secreted by testes.
Answer:
Testosterone.

Question 16.
Which hormone is secreted by ovaries 7
Answer:
Estrogen.

Question 17.
Which endocrine gland is called the master gland?
Answer:
Pituitary gland.

Question 18.
What are hormones secreted by testes and ovaries called collectively?
Answer:
Sex hormones.

Question 19.
Name the sex hormones secreted by testes and ovaries.
Answer:
Testosterone and Estrogen.

Question 20.
Name any one hormone secreted by Pituitary gland.
Answer:
Follicle stimulating Hormone or FSH.

Question 21.
Which hormone is responsible for the maturity of ova or sperms?
Answer:
Follicle stimulating hormone.

Question 22.
What is the common name given to ova and sperms?
Answer:
Gametes.

Question 23.
What is the beginning of menstruation called?
Answer:
Menarche.

Question 24.
What is the stoppage of menstruation called?
Answer:
Menopause.

Question 25.
What are the names given to sex chromosomes?
Answer:
X and Y.

Question 26.
Which sex chromosome determines the sex of body?
Answer:
Y Chromosome.

Question 27.
Which hormone is secreted by thyroid?
Answer:
Thyroxin.

Question 28.
Which hormone is secreted by pancreas?
Answer:
Insulin.

Question 29.
Which hormone controls the blood sugar level?
Answer:
Insulin.

Question 30.
Which hormone is secreted by Adrenal glands?
Answer:
Adrenalin.

Question 31.
Which hormone is called stress hormone?
Answer:
Adrenalin.

Question 32.
Why adrenalin is called stress hormone?
Answer:
Adrenalin is called stress hormone because it helps to calm down when one is angry.

Question 33.
What is a balanced diet?
Answer:
Diet containing all the necessary minerals in right proportion is called a balanced diet.

Question 34.
Name any food, which is called a balanced food in itself.
Answer:
Milk.

Question 35.
Which virus causes AIDS?
Answer:
HIV.

Short Answer Type Questions

Question 1.
What is adolescence?
Answer:
The phase of a person’s life, when his body undergoes changes to attain reproductive maturity is called adolescence. Adolescence begins at the age of 13 and lasts till the age of 18 or 19 years.

Question 2.
What are the signs of adolescence?
Answer:
Certain body changes mark the onset of puberty. Hairy line above lips in boys and sudden increase in height are the signs of puberty. In girls developing breasts show the on set of puberty.

Question 3.
Why some boys or girls have improportionate body parts during adolescence 7
Answer:
Some times the boys and girls have improportionate body parts. They look tall but face look smaller or other tilings. This is because all body parts do not grow at the same rate. But slowly they all catch up and body becomes balanced.

Question 4.
What changes take place in the body of adolescents during this period?
Answer:
Many changes take place in the bodies of boys and girls during adolescence. Their shoulders become wider and chest becomes broader. Girls get developed breasts and their hips become wider. Muscles of boys grow more than the girls.

Question 5.
What changes occur in the voice of boys and girls during puberty?
Answer:
The voice box or the larynx begins to grow. Boys have more grown voice box. It can be seen as the protrubed part in their throat.
Their voice becomes deep and sometimes, it grows more than controlled limit and their voice become hoarse. Girls get a high pitched voice.

Question 6.
What causes the changes in human body during puberty?
Answer:
The changes which occur during puberty are caused due to some chemical substances secreted by glands. These chemical substances are acalled Hormones. Endocrine system in human body has various glands, which secrete many important hormones which help the body to grow and mature.

Question 7.
How do sex hormones work in human body?
Answer:
In males the testosterone is secreted by testes and it causes growth of moustaches and beard. In girls estrogefi causes the development of mammary glands . They develop inside the breast and cause enlargement of breasts.

Question 8.
How does pituitary gland initiate the puberty in humans?
Answer:
Pituitary gland is called the master gland. It stimulates the testes and ovaries to produce sex hormones i.e. Testosterone and estrogen. These sex hormones further initiate the changes in body to attain sexual maturity.

Question 9.
What is menstruation?
Answer:
Monthly bleeding in women is called menstruation, when egg is matured and released by ovaries. It if not fertilized is dispelled by body along with the thick lining of uterus and with blood vessels. It is released from the body in form of monthly bleeding. It is called menstruation.

Question 10.
How the sex of the body is determined?
Answer:
Every human beings have 23 pairs of chromosomes in the nuclei of their cells. A pair of sex hormones are also among them. Females have XX sex chromosomes and males have XY sex chromosomes, when after fertilization the zygote get both X chromosomes from male and female, it will develop into a baby girl. When the zygote get X chromosome from female and Y from male, then it develops into a male. Thus the chromosome from a male decides if a baby will be a male or a female.

Long Answer Type Questions

Question 1.
What changes occur in body during puberty?
Answer:
Various changes occur in the body of human beings during puberty. These changes occur due to hormones secreted by reproductive organs. These changes are the following:
(a) Physical changes:
Various changes occur in the bodies of boys and girls. Boys get broader shoulders and wider chest. Sudden increase in their height is accompanied by growth of hair on their body parts. They get moustaches and beard.Girls get developed breasts and wider hips. More secretions from sweat and oil glands cause pimples and acnes in some young people.

(b) Change in Voice:
Voice of boys become deep due to enlarged larynx. Some time more growth in voice box is visible as Adam’s Apple in their throats. Their voice becomes even coarse in case of extra growth of larynx. Voice of girls become high pitched.

(c) Development of Sex Organs:
The reproductive organs of boys and girls become active. Testes start producing sperms and ovaries release matured eggs. Mental and Emotional Maturity: Young people become more mature mentally, emotionally and intellectually.

Question 2.
How are the changes of adolesence controlled by hormones?
Answer:
The endocrine system of body secretes many chemical substances which are directly poured into the blood stream, these chemical substances are called hormones. All changes taking place during adolescence are controlled by these hormones.

Pituitary glands secrete growth hormones which stimulates the sex organs to release hormones.. Testes start secreting testosterone and ovaries start secreting estrogen. These sex hormones cause secondary sexual characters. Estrogen causes development of mammary glands which develop under breast, thus breast starts enlarging in females.

Question 3.
How can bad habits like Drug addiction harm the young people?
Answer:
Boys and girls feel a little bit insecure and confused during adolescence due to sudden changes in their bodies. This can mislead them to certain unhealthy and immoral habbits, like drug addiction and many others. Drug addiction is a very bad habit which can spoil our lives. It is easy to start, taking drugs but very difficult to shun this habit. Drugs can cause many long term harms on our bodies.

They make our body weak and prone to many communicable diseases like AIDS and many other sexual disorders. AIDS virus HIV can pass on to a healthy person from an infected person by sharing the infected syringe. The drug addicts inject drugs by using syringe. The same syringe is shared by other addicts also, so the infected syringe can spread AIDS to others also.

Question 4.
Who is responsible to determine the sex of unborn baby: Father or mother?
Answer:
Each human being have 23 pairs of chromosomes in the nuclei of every cell. These chromosomes contain the hereditary information. Out of these chromosomes a pair of chromosome are called sex chromosomes, which are named X and Y Chromosomes. Each female has 2 X chromosomes while the males have one X chromosome and one Y chromosome. The unfertilized egg released by ovaries always have one X chromosome. Testes produce some sperms with X chromosome and some with Y chromosome.

If sperms with X chromosome fertilize with egg with unborn is a female, but if the sperms with Y chromosome fertilizes with egg, then the unborn baby will be a male. So, it becomes clear that it is the sperm released by father carrying X or Y chromosomes, that determines the sex of the unborn baby.

Question 5.
What should be done to maintain reproductive health?
Answer:
Following measures can help the young people to maintain their reproductive health.
(i) Balanced Diet:
Diet is very important for a growing body. Diet should be a balanced diet. Balanced diet contains all the necessary elements in required proportion. Elements like carbohydrates, proteins, fats and vitamins should be integral part of a balanced diet. Milk provides all the required elements in required proportion. Junk and fast food are good to taste but they are not nutritious so they should not be included in diet.

(b) Personal Hygiene:
One should keep one’s body clean by bathing everyday. All parts of the body should be washed properly because infections can take place due to more sweat and oil secretion by sweat and oil glands.

(c) Physical Exercise:
Daily routine of physical exercise can keep body fit and circulation of blood gets maintained providing energy to all parts of the body.

Reaching the Age of Adolescence Class 8 HBSE Notes

1. A baby becomes adult after passing a few development stages.
2. The age at which a child becomes capable of reproduction is called adolescence.
3. At the age of 11 years to 19 years a child reaches puberty.
4. Reproductive organs start developing as the puberty sets in.
5. Various changes occur in the bodies of boys and girls at age of puberty. Hair starts growing at different parts of body. Girls have developed breasts, heavy hips, boys get.moustaches and beard, their voice become heavy.
6. Height gain is prominent at age of puberty along with other changes. Hormones starts taking control of the reproductive organs, and make the beginning of maturity of reproductive organs.
7. Hormones are the chemical substances which are secreted by the pituitary glands directly into the blood stream.
8. Growth hormones stimulate other glands to secrete various other hormones to control various other body functions.
9. Various hormones secreted by different glands perform various functions. Ovaries and testes secrete hormones for sexual maturity, pancreas secrete Insulin to control sugar level, thyroid secret thyroxin and adrenal glands produce adrenalin. All these hormones are necessary for proper growth and development of body.
11. With onset of puberty females have hormones like estrogen. They have their uterine wall prepared to receive the fertilized egg. They have another phenomenon called menstruation. In this phenomenon they get the unfertilized egg flown out of body through blood.
12. Reproductive health needs a lot of care and one needs to maintain hygiene and physical activity.
13. Proper nutrition and balanced diet in necessary for growing body, so it should be taken care of.

Haryana State Board HBSE 8th Class Science Solutions Chapter 9 Reproduction in Animals Textbook Exercise Questions and Answers.

Haryana Board 8th Class Science Solutions Chapter 9 Reproduction in Animals

HBSE 8th Class Science Reproduction in Animals Textbook Questions and Answers

Question 1.
Explain the importance of reproduction in organisms.
Answer:
Reproduction is very important for the organisms. The organisms reproduce to produce young ones like them. It carries on their generation. If reproduction does not take place, no living being would survive on earth. Secondly, specials characters of an organism are carried over to its next generation through reproduction only.

Question 2.
Describe the process of fertilization in human beings,
Answer:
Human beings reproduce sexually. In human beings fertilization takes place internally i.e. inside female body. Males eject sperms inside females body. Sperms and ovum fuse to form the fertilized egg called zygote. During this process the nucleus of the sperm fuses with the nucleus of the ovum thus forming a single nucleus.
Thus zygote is formed with a single nucleus, this completes the process of fertilization.

Question 3.
Choose the most appropriate answer:
(a) Internal fertilisation occurs:
(i) in female body
(ii) outside female body.
(iii) in male body.
(iv) outside male body.
Answer:
(a) In female body

(b) A tadpole develops into an adult frog by the process of:
(i) fertilization
(ii) metamorphosis.
(iii) embedding
(iv) budding.
Answer:
(b) metamorphosis

(c) The number of nuclei present in a zygote is:
(i) none
(ii) one
(iii) two
(iv) four
Answer:
(c)two.

Question 4.
Indicate whether the following sentences as True (T) or False (F):
(a) Oviparous animals give birth to young ones. ( )
(b) Each sperm is a single cell. ( )
(c) External fertilisation take place in frog. ( )
(d) A new human individual developed from a cell called gamete. ( )
(e) Egg laid after fertilisation is made up of a single cell. ( )
(f) Amoeba reproduces by budding. ( )
(g) Fertilisation is necessary even in asexual reproduction. ( )
(h) Binary fission is a method of asexual reproduction. ( )
(i) A zygote is formed as a result of fertilisation. ( )
(j) An embryo is made up of a single cell.( )
Answer:
(a) False
(b) True
(c) True
(d) False
(e) True
(f) False
(g) False
(h) True
(i) True
(j) False.

Question 5.
Give two differences between a zygote and a foetus?
Answer:
(i) Zygote is made up of a single cell while foetus is made up of many cells.
(ii) Zygote does not have well developed limbs, foetus has well developed and identifiable limbs.
(iii) Zygote is formed by the fertilization of sperms and ovum, foetus is formed by the repeated divisions of the zygote .

Question 6.
Define asexual reproduction. Describe the two methods of asexual reproduction in animals.
Answer:
Asexual reproduction is that type of reproduction in which only single parent is involved. Asexual reproduction takes place by different methods like budding, binary fission etc. Let us discuss these two methods:
(i) Budding:
This type of reproduction takes place in Hydra and Bacteria. A part of the organism starts bulging out. Slowly it grows and develops into a separate individual.

(ii) Binary fission:
In this type of reproduction, a single organism gets divided into two. This type of reproduction takes place in Amoeba. The nucleus of the Amoeba gets divided into two followed by division of their bodies, each part getting one nucleus and developing into separate individual.

Question 7.
In which female reproductive organ does the embryo get embedded?
Answer:
Uterus.

Question 8.
What is metamorphosis? Give examples.
Answer:
Drastic changes which take place during the development of an animal is called metamorphosis. Animals like frog, butterfly undergo metamorphosis.

Question 9.
Differentiate between internal fertilisation and external fertilisation.
Answer:
Internal fertilisation takes place inside the body of the female while the external fertilisation takes place outside the body of the female.
In case of internal fertilisation sperms are ejaculated in female’s body by the male. In external fertilisation sperms are discharged in I open.

Question 10.
Complete the cross-word puzzle using the hints given below.
Across:
1. The process of the fusion of the gametes.
6. The type of fertilization in hen.
7. The term used for bulges observed on the sides of the body of Hydra.
8. Eggs are produced here.

Down:
2. Sperms are produced in these male reproductive organs.
3. Another term for the fertilized egg.
4. These animals lay eggs.
5. A type of fission in amobea.

Answer:

Extended Learning – Activities And Projects

1. Visit a poultry farm. Talk to the manager of the farm and try to find out the answers to the following:
(a) What are layers and broilers in a poultry farm?
(b) Do hens lay unfertilised eggs?
(c) How can you obtain fertilised and unfertilised eggs?
(d) Are the eggs that we get in the stores fertilised or unfertilised?
(e) Can you consume fertilised eggs?
(f) Is there any difference in the nutritional value of the fertilised and unfertilised eggs?
Answer:
For self attempt.

2. Observe live hydra yourself and learn how they reproduce by doing the following activity:
During the summer months collect water weeds from ponds or ditches along with the pond water and put them in a glass jar. After a day or so you may see several hydra clinging to the sides of the jar.

Hydra is transparent, jelly-like and with tentacles. It clings to the jar with the base of its body. If the jar is shaken, the hydra will contract instantly into a small blob, at the same time drawing its tentacles in.

Now take out few hydras from the jar and put them on a watch glass. Using a hand lens or a binocular or dissection microscope, observe the changes that are taking place in their body. Note down your observations.
Answer:
For self attempts.

3. The eggs we get from the market are generally the unfertilized ones. In case you wish to observe a developing chick embryo, get a fertilized egg from the poultry or hatchery which has been incubated for 36 hours or more. You may then be.able to see a white disc-like structure on the yolk. This is the developing embryo. Sometimes if the heart and blood vessels have developed you may even see a red spot.
Answer:
For self attempt.

4. Talk to a doctor. Find out how twinning: occurs. Look for any twins in your neighbourhood, or among your Mends. Find out ifthe twins are identical or non-identical. Also find out why identical twins are always of the same sex? If you know of any story about twins, write it in your own words.
You could visit the following website for information on twins: www.keepkidshealthy.com/twins/ expecting_twins.html.
For more information , on animal reproduction, you can vjsit:

• www.Saburchill.com/chapters/ chap0031.html
• healthhowstuffworks.com/human- reproduction.htm
• www.teenshealth.org/teen/sexual_health

Answer:
For self attempt.

HBSE 8th Class Science Reproduction in Animals Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Name different modes of reproduction.
Answer:
Sexual reproduction and asexual reproduction.

Question 2.
Define sexual reproduction.
Answer:
When male and female organisms are involved in reproduction, it is called sexual reproduction.

Question 3.
Define asexual reproduction.
Answer:
When only single parent involved, reproduction is called asexual reproduction.

Question 4.
What is another name for ovum or sperm?
Answer:
Gametfe.

Question 5.
What is fertilization?
Answer:
When male and female gametes fuse, it is called fertilization.

Question 6.
What is formed when male and female gametes fuse?
Answer:
Zygote.

Question 7.
Name female reproductory organs.
Answer:
Ovaries, oviduct, uterus.

Question 8.
Name male reproductory organs.
Answer:
Testes, sperm ducts and penis.

Question 9.
Name the female gamete produced by ovaries.
Answer:
Ova.

Question 10.
Which male organ produce male gamete?
Answer:
Testes.

Question 11.
Name male gamete produced by testes.
Answer:
Sperms.

Question 12.
Name the hind of fertilization *hich take, pUce inside fem.le. body.
Answer:
Internal fertilization.

Question 13.
What kind of fertilization takes place in humans?
Answer:
Internal fertilization.

Question 14.
What type of fertilization takes place in frogs?
Answer:
External fertilization.

Question 15.
What does a zygote develop into?
Answer:
Embryo.

Question 16.
Where does an embryo grow in case of internal fertilization?
Answer:
In uterus.

Question 17.
What does an embryo grow into?
Answer:
Foetus.

Question 18.
Where does an embryo grow in case of external fertilization?
Answer:
Out side in open.

Question 19.
What are the animals called, who give birth directly to young one?
Answer:
Viviparous animals.

Question 20.
Give at least two examples of viviparous animals.
Answer:
Humans and cows.

Question 21.
What are the animals called, who lay eggs first?
Answer:
Oviparous animals.

Question 22.
Give any two examples of oviparous animals.
Answer:
Hen, Frog.

Question 23.
How many developing stages an egg of a frag undergoes to become an adult?
Answer:
Three: Egg, Tadpole, larvae, adult.

Question 24.
What do we call the sudden and extreme changes taking place during the development of an animal?
Answer:
Metamorphosis.

Question 25.
Name any two methods of asexual reproduction.
Answer:
Budding and Binary fission.

Question 26.
Name any animal undergoing budding for reproduction.
Answer:
Hydra.

Question 27.
Name tuny animal undergoing Binary fission to reproduce,
Answer:
Amoeba.

Short Answer Type Questions

Question 1.
What is reproduction? Why is it important?
Answer:
Reproduction is giving birth to organisms of same kind. Reproduction is important to continue life on earth and to maintain different special characters of different species.

Question 2.
What are different modes of reproduction?
Answer:
Reproduction takes place by two methods. In one method a single parent is involved in the process of reproduction. This is called asexual reproduction. In second method both male and female i.e. both parents are involved in the process of reproduction. This kind of reproduction is called sexual reproduction.

Question 3.
What are the names of male reproductory organs in human beings?
Answer:
In human beings male reproductory organs are a pair of testes, sperm ducts and a penis. Testes are responsible for producing male gametes called sperms. They are transported to the sperm ducts and through the penis, they are ejaculated in female body.

Question 4.
Explain the reproductory organs of female in human beings.
Answer:
In human beings the female reproductoiy organs are a pair of ovaries, oviducts or fallopian tubes and the uterus. Ovaries are responsible to produce female gamete called ova, which fertilize with male sperm in female fallopian tube and travels to uterus for its development into embryo and the foetus.

Question 5.
Describe the human male and female gametes.
Answer:
In human beings the males produce the gamete called sperms. Sperms are very small in size. They have a head with a middle piece which end into a tail. It is a single cell. Similarly, female gamete ova is produced by ovaries. Every ova is a single cell and one matured ova is released by one ovary every month.

Question 6.
What is fertilisation?
Answer:
When a male and a female gamete come in contact with each other they fuse. The male sperm enters the female ova and the nucleus of the sperm fuses with nucleus of the ova and results into a single nucleus. This whole process is called fertilization. In short fertilisation is the fusion of male and female gametes.

Question 7.
Explain how external fertilization takes place?
Answer:
In this case the females lay eggs in slow moving streams. The males also release sperms on this cluster of eggs. The sperms move in water with the help of tail and when come in contact with egg, they get fertilized.

Question 8.
How is an embryo formed put of a zygote?
Answer:
Zygote is a single cell formed by the fusion of male and female gametes. It undergoes repeated numbers of division to form a lot of many cells, so that the limbs and other parts can be developed. Thus a single zygote gets divided to form an embryo.

Question 9.
How is an embryo formed in case of hens?
Answer:
In hens zygote divides many times and reaches the oviduct. During this a protective outer coating is formed around the embryo. The complete embryo develops inside this protective shell. This embryo is laid by the hen along with the shell as an egg. This egg finally hatches after ‘ three weeks to produce chick.

Question 10.
What is budding?
Answer:
Budding is an asexual method of reproduction in animals. It needs only a single parent to reproduce. The body of the animal starts developing a small bulging structure called bud which slowly grows and have itself disconnected from the parent animal and becomes a separate individual. This is called budding. Animals like hydra reproduce through budding.

Question 11.
What do you mean by binary fission?
Answer:
Binary fission is a method of asexual reproduction. In this method the body of the animal divides into two halves. The nucleus of the body divides into two and this is followed by the division of the whole body. So, two organisms get produced with separate nuclei. Animals like Amoeba reproduce by this method.

Question 12.
What is cloning?
Answer:
Cloning is a method of producing an identical organism, a body part or only a cell. The produced organism or cell is completely identical to its original organism or cell. This method has been used many times in animals to produce identical clones.

Long Answer Type Questions

Question 1.
What do you mean by reproduction? Write about different modes of reproduction.
Answer:
Reproduction is the process of producing young ones of the same kind. Reproduction is a very important process. It is the only means of keeping the life on the earth.
There are two modes of reproduction:
(i) Sexual Reproduction:
Reproduction process in which a male and a female parents are involved is called sexual reproduction. In this process both parents produce gametes which fertilize to produce a zygote, which further develops into a baby. Human beings, cows, dogs etc. reproduce sexually.

(ii) Asexual Reproduction:
When a single parent is responsible for producing a young one, it is called asexual reproduction. Budding, fragmentation, spore formation Binary fission etc. are different methods of asexual reproduction. Microorganisms like Hydra, Amoeba, bacteria etc. reproduce asexually.

Question 2.
Draw and describe the male reproductive organs in humans.
Answer:
Male reproductive organs consist of a pair of testes, sperm ducts and penis. Testes are responsible for producing male gamete called sperm. Sperm is very small in size. It has a head, a middle piece and a tail. Sperms travel through sperm ducts and penis, and are released in female body for fertilization.

Question 3.
Draw and explain the Female Reproductive organs in human.
Answer:
Female reproductive organs consist of a pair of ovaries, oviduct or fallopian tubes and uterus.

Ovaries produce the female gamete called Ova. Every month an ovary produces an ovum. The ovum and sperm fertilize inside fallopian tubes and the fertilized zygote travels to the uterus and attach with its wall to develop into the foetus.

Question 4.
What is fertilization? How does it take place?
Answer:
Fertilization is the process by which the male and female gametes fuse to form the zygote. The sperms from a male are transferred into the female body. They swim to the fallopian tubes with help of their tails and one of them enters the ovum to fertilize. When the sperm enters the ovum, the nucleus of both the gametes fuse with each other to form the fertilized zygote.

The fertilized egg is called zygote. This zygote develops into foetus by repeated cell division. When the fertilization takes in the body of female, it is called internal fertilization. But many animals release their gametes into water and fertilization takes place outside the body of female, then the fertilization is called the external fertilization.

Question 5.
What is asexusal reproduction? Describe different methods of asexual reproduction.
Answer:
The reproduction in which only a single parent is involved is called asexual reproduction. This type of reproduction takes place mostly in microoganisms. Following are the methods of asexual reproduction:
(i) Budding:
This type of reproduction takes place in Hydra. The body of the hydra starts developing small bulges. These bulges are called buds. These buds grow in size and finally get detached from its body and become a separate individual.

(ii) Binary Fission:
This type of reproduction takes place in Amoeba. The body of the organism divides into two. The nucleus of the organism divides into two and then the body of Amoeba divides, each part getting each nucleus and thus becoming two separate individuals.

Reproduction in Animals Class 8 HBSE Notes

1. Each living being reproduce to give birth to young ones exactly like them.
2. The process by which young ones are produced is called reproduction.
3. Reproduction is of two types: Sexual reproduction and asexual reproduction.
4. When a male and a female gamete fuse to give birth to a young ones, then it is called sexual reproduction.
5. When a single parent is involved in reproduction, then it is called asexual reproduction.
6. Reproductive organs in males and females are different. In females the reproductive organs are ovaries oviducts and uterus. In males the reproductive organs are a pair of testes, sperm ducts and penis.
7. Ovaries produce female gamete called ovum and male gamete called sperms are produced by testes.
8. Ovum and sperm fuse to form egg called Zygote. The process of fusion of ovum and sperm is called fertilization.
9. Fertilization is of two types: When it takes place inside the females body, then it is called internal fertilization, but when ovum and sperms fuse out side the body, it is called external fertilization.
10. Embryo is formed from the zygote by repeated divisions, which grows in the uterus of the female in case of internal fertilization. Embryo grows into foetus when it gets well developed limbs.
11. When animals give birth to a young one it is called a viviparous animals e.g. man, cow etc. When animals lay eggs, they are called oviparous animals e.g. hen, butterfly, etc.
12. In asexual reproduction organisms reproduce by budding binary fission, fragmentation etc.

Haryana State Board HBSE 8th Class Science Solutions Chapter 8 Cell Structure and Functions Textbook Exercise Questions and Answers.

Haryana Board 8th Class Science Solutions Chapter 8 Cell Structure and Functions

HBSE 8th Class Science Cell Structure and Functions Textbook Questions and Answers

Question 1.
Indicate whether the following statements are True (T) or False (F).
(а) Unicellular organisms have one-celled body. (T/F)
(б) Muscle cells are branched structures. (T/F)
(c) The basic living structure of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)
Answer:
(a) True
(b) True
(c) False
(d) True

Question 2.
Make a sketch of the human nerve cell. What function do nerve cells performs?
Answer:
Functions of human nerve cell:
(i) Nerve cells receive messages from different parts of body.
(ii) They further transfer these message to brain and brain further send commands for functioning Long Branched Nerve Cell of different organs.

(iii) They coordinate functioning of different organs of body.

Question 3.
Write short notes on the following:
(а) Cytoplasm
(b) Nucleus of a cell.
Answer:
(a) Cytoplasm:
Cytoplasm is a jelly like substance which is present between the cell membrane and the nucleus. Various other organelles of cells are present in the cytoplasm. Cytoplasm is made up of chemical substances like carbohydrates, proteins and water. These chemical substances are present in cells of all types and sizes.

(b) Nucleus of a cell:
Nucleus is the master of the cell. It commands all the functioning of the cell. It is generally located in the centre of the cell and is spherical in structure. A membrane called nuclear membrane separates it from cytoplasm. It contains the genetic material (DNA, RNA) in it. This porous membrane allows the transfer of material in the nucleus and cytoplasm. Nucleus contains a dense body called nucleolus which actually contain chromosomes the genetic material.

Question 4.
Which part of the cell contains organelles?
Answer:
Cytoplasm.

Question 5.
Make sketches of animals and plant cells. State three differences between them. Answer:

Question 6.
State a difference between eukaryotes and prokaryotes.
Answer:
Prokaryotes do not have a well designed nuclear membrane, while Eukaryotes have a well designed nuclear membrane.

Question 7.
Where are chromosomes found in a cell? State their function.
Answer:
Chromosomes are found in the nucleus of a cell. Their function is to carry characteristic features of parent cells to the daughter cell i.e. from parent to offsprongs.

Question 8.
‘Cells are the basic structural units of living organism’. Explain.
Answer:
Cells are the basic structural units of living organisms because lot of cells unit to form and many tissues form an organ. And organs combine to form a complete body, so cell is the basic structural unit of an organism. All basic function for the survival of an organism take peace inside cells so they are the basic functional units of a living being.

Question 9.
Explain why chloroplasts are found only in plant cells?
Answer:
Chloroplasts are only found in plant cells because they are required for the food making process of plants called photosynthesis.

Question 10.
Complete the following crossword with the help of clues given below:
Across
1. This is necessary for photosynthesis.
3. Term for component present in the cytoplasm.
6. The living substance in the cell.
8. Unit of inheritance present on the chromosomes.

Down
1. Green plastids.
2. Formed by collection of tissues.
4. It separates the contents of the cell from the surrounding medium.
5. Empty space in the cytoplasm.
7. A group of cells.

Answer:

Extended Learning – Activities And Projects

1. Visit a laboratory for senior secondary students in your school or in a neightbouring school. Learn about the functioning of a microscope in the laboratory. Also observe how a slide is observed under the microscope,
Answer:
For self attempt.

2. Talk to the senior biology teacher in your school or a neighbouring school. Find out if there are diseases which are passed on from parents to the offspring. Find out how these are carried and also if these diseases can be treated. For this you can also visit a doctor.
Answer:
There are certain diseases which are passed on from parent to the offspring. Diseases like diabites, heart diseases, certain skin diseases like leukoderma, etc. are genetic diseases.

3. Visit an agriculture extension centre in your area. Find out about genetically modified (GM) crops. Prepare a short speech for your class on this topic. You may visit www.usc.ernet.in / currsci / sep2520Ql/ 655.pdf
Answer:
For self attempt.

4. Find out about Bt cotton from an agriculture expert (or from envfor.nic.in/ division/csnrv/btcotton/b gnote.pdf). Prepare a short note on its advantages / disadvantages.
For more on cell, visit: www.enchantedlearning.com/subjects/ plants/ cell/
Answer:
For self attempt.

HBSE 8th Class Science Cell Structure and Functions Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Define a cell.
Answer:
A cell is the basic structural and functional unit of living things.

Question 2.
Who discovered cell?
Answer:
Robert Hooke.

Question 3.
Name three important parts of cell.
Answer:
(i) Cell membrane
(ii) Cytoplasm
(iii) Nucleus

Question 4.
In which cells, cell wall is present?
Answer:
In plant cells.

Question 5.
Give three examples of unicellular organisms.
Answer:
Amoeba, Paramecium, Chlamydomonas.

Question 6.
Where are chromosomes present in a cell?
Answer:
Nucleus.

Question 7.
Name the cell part that has tiny holes.
Answer:
Cell Membrane

Question 8.
Which cell organelle is found only in animal cell?
Answer:
Centrosome.

Question 9.
Name the cells organelle which is found only in plant cell.
Answer:
Plastids.

Question 10.
How do cells increase in numbers?
Answer:
By cell division.

Question 11.
Which organelle is called the ppwer house of the cell?
Answer:
Mitochondria.

Question 12.
Which organelle is called suicidal bags of the cell?
Answer:
Lysosomes.

Question 13.
What does mitochondria do?
Answer:
It prepares food for plants.

Question 14.
What does chromosomes do?
Answer:
Transfer chracters from one generation to another generation.

Question 15.
What does ribosomes do?
Answer:
They help in synthesis of proteins.

Question 16.
Name plastids found in plant cells.
Answer:
Chloroplasts, Leucoplast and chromoplast.

Question 17.
What is the unit of measuring the size of the cell?
Answer:
Microns.

Question 18.
Name the longest cell.
Answer:
Nerve cell in animal.

Question 19.
Name the heaviest animal cell.
Answer:
Ostrich Egg.

Question 20.
Name the largest plant cell.
Answer:
Acetabulum.

Question 21.
Name the smallest plant cell.
Answer:
Bacteria.

Short Answer Type Questions

Question 1.
Why cells are called building blocks of life?
Answer:
Cells like bricks of a building are basic structural units of living organisms. Buildings differ from each other, organism also differ from each other. Both are basic unit of structure. So, they are called building blocks of life.

Question 2.
Why are the mitochondria known as the power housd of the cell?
Answer:
They are rod shaped and very minute. They are concerned with the release of energy from food during respiration. Because of this, they are often referred to as the power house of the cell.

Question 3.
What are the cell organelles? What are their functions?
Answer:
Cell organelles are small active living structures found in cytoplasm of cell. Each organelle has different structure and performs different function for cell. They are endoplasmic reticulum, Plastides, Mitochondria, Ribosomes, Golgi bodies, Centrosomes, Lysosomes, Vacoules.

Question 4.
What is meant by protoplasm?
Answer:
The cytoplasm surrounded by the cell membrane and enclosing the nucleus together constitute the protoplasm. Protoplasm in other words, includes the cell membrance, the nucleus and the Cytoplasm.

Question 5.
Name four elements which form major part of protoplasm?
Answer:
Ninety nine percent of protoplasm by its weight is made up of four elements. Namely; Carbon, Hydrogen, Nitrogen and Oxygen. It also contains other elements such as H20, Carbohydrates, fats, proteins and mineral acids. Both elements and compounds in unique combination provide living nature to the protoplasm.

Question 6.
Why cells could not be observed before 17th century?
Answer:
The main reason was that the size of the majority of the cells are too small to be invisible to the unaided eye and at that time microscope was not discovered. So, the cell could not be observed before 17th century.

Question 7.
Why Hooke had to take thin slices of cork?
Answer:
The cork was solid and the details of cork could not seen in solid state. So he made thin slices to see the details of the cork. He saw space in cork slice which appeared like honey comb, called these compartments as cells.

Question 8.
What do you know about cell shape?
Answer:
Cells are of diverse shapes. Some cells are like Amoeba and white blood cells of our blood. They continuously change their shape. Most cells, however, maintain a constant shape all through their existence.

Question 9.
Write about size variation of the cells.
Answer:
Cells vary in their size. The smallest known cell is bacteria measuring about 0.5 micrometre. Nerve cell is up to 1 metre long. The heaviest cell is of ostrich and acetabulum is the largest unicellular algae which is about 10 cm long. Majority of cells in plants and animals range from 20 to 30 microns in diameter.

Question 10.
Write a short note on cell numbers.
Answer:
Cells are of two types depending upon their number. Some cells exist single in number. The organism consisting of a single cell are called unicellular organisms. The organisms which consist of two or more than two cells are called multicellular organisms. Human body consists of more than a trillion of cells. Amoeba,Paramecium etc. are unicellular organisms.

Question 11.
What is nucleolus?
Answer:
Nucleolus is a small spherical dense body present in the nucleus. It is only visible, with a microscope of a higher magnification.

Long Answer Type Questions

Question 1.
How do you differentiate protoplasm from cytoplasm?
Answer:
Protoplasm:
The cytoplasm surrounded by the cell membrane and enclosing the nucleus together constitute the protoplasm. In other words the cell membrane, the cytoplasm and the nucleus constitute pr’otoplasm.

Cytoplasm:
It is jelly like substance occupied most of the inside of the cell. It occupies the space between the cell membrane and the nucleus. All the life functions take place in the cytoplasm. It contains many important tiny structures called the organelles, which performs the various life functions.

Question 2.
Write the functions of cell organelles.
Answer:
(i) Mitochondria: It performs the function of respiration provide the cell with energy.
(ii) Endoplasmic-reticulum: It is a network of membrane, it provides large surface area for life function to take place.
(iii) Chloroplasts: These are green in colour, contain green pigment chlorophyll which help in food manufacturing in plants.
(iv) Golgi complex: These collect and distribute substances made in the cell. Synthesis and secretions of many materials.
(v) Lysosomes: Certain enzymes which help in breaking down or destroying various unwanted materials of cell.
(vi) Centrioles and centrosome: It helps in cell division in animal cells.
(vii) Ribosomes: They help in protein synthesis.
(viii) Vacoules: These are generally stored inside clear space in the cytoplasm.
In animal cells they are very small. In plant cells they are large and greater in number.

Question 3.
Differentiate between the plant cell and the animal cell.
Answer:

Animal Cell	Plant Cell
(i) Cell wall is absent.	(i) A rigid cell wall is present.
(ii) Chloroplasts are absent.	(ii) Chloroplasts are present.
(iii) Centrosome is present near the nucleus.	(iii) Centrosome is absent.

Cell Structure and Functions Class 8 HBSE Notes

1. All organisms are made of small basic structural and functional units.
2. These smallest functional units are called cells.
3. Robert Hooke observed a cell for the first time in 1665.
4. Cells can be defined as the basic structural and functional unit of life.
5. Cells are of different size and shape.
6. Living Organisms made up of a single cell are called unicellular organisms.
7. All unicellular organisms are microscopic organism e.g. Amoeba, Paramecium etc. i.e. they cannot be seen with naked eyes.
8. Some cells can be seen with naked eyes without any aid e.g. egg of a hen.
9. In unicellular organisms, the single cell perform all the function necessary for living.
10. A cell has different parts. These small parts of the cell are called organelles.
11. A cell is made up of cell membrane, which contains all the organelles in it.
12. All cell organellies are contained in cytoplasm.
13. In the centre of the cytoplasm nucleus is situated, which is the brain of the cell.
14. Mitochondria, Endoplasmic reticulum, chloroplasts, golgi complex, lysosomes, centrioles, and ribosomes are other cell organelles.
15. Cells which don’t have a well organized nuleus are called the karyotic cells. In these cells the nucleus lacks the nuclear membrane.
16. The cells of plants are a bit different from that of animals.
17. In animals, cell wall, chloroplast, chromosomes, vacoules are absent, while they are present in plant cells.
18. Green leaves have a special organelle called chlorophyll i.e. the Green plastids (chloroplasts) which helps in the process of photosynthesis.
19. Different colours of plastids give different colours to plants.

Haryana State Board HBSE 8th Class Science Solutions Chapter 7 Conservation of Plants and Animals Textbook Exercise Questions and Answers.

Haryana Board 8th Class Science Solutions Chapter 7 Conservation of Plants and Animals

HBSE 8th Class Science Conservation of Plants and Animals Textbook Questions and Answers

Question 1.
Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called ………….. .
(b) Species found only in a particular area is known as ………….. .
(c) Migratory birds fly to far away places because of …………. changes.
Answer:
(a) wildlife sanetuary
(b) Endemic species
(c) climate.

Question 2.
Differentiate between the following:
(a) Wildlife sanctuary and biosphere reserve.
(b) Zoo and wildlife sanctuary.
(c) Endangered and extinct species.
(d) Flora and fauna.
Answer:
(a) Wildlife sanctuary is a place where wild animals are protected and preserved. Here poaching or capturing any animal is strictly prohibited. Biosphere reserves are the protecting areas meant for only conservation of biodiversity i.e. animals and plants and even the microorganisms. It also helps to maintain the culture of that area. It contains many wildlife sancturies, national parks.

(b) Zoos are smaller places having some animals protected for the public view, while wildlife sancturies protect and conserve wild animals in their natural habitats. They are spread in vast areas.

(c) Endangered species are those species which are at the verge of extinction and which are required to be protected and conserved, while extinct species are those which no more exist on the earth.

(d) Flora is the term used for wide variety of plants while fauna is used to refer to all the varieties of animals.

Question 3.
Discuss the effects of deforestation on the following:
(a) Wild animals
(b) Environment
(c) Villages (Rural areas)
(d) Cities (Urban areas).
(e) Earth
(f) The next generation.
Answer:
(a) Wild animals:
When forests are cut, they leave many wild animals unsheltered. Their habitat is snatched away from them and they are left to die without their natural shelter.

(b) Environment:
Environment is adversely effected by deforestation as ecological balance is disturbed. Carbondioxide is not absorbed by plants and it gets accumulated to cause global warming.

(c) Villages (Rural areas):
Villages are depended upon forests to large extent. They are closely related to forests. Some adjoining villages have to face the wrath of wild animals as unhabitated animals run to nearby villages and cause danger to them. Morever they are devoid of other benefits like fruits, fuel, wood etc. they get from forests.

(d) Cities (Urban areas):
Cities are not directly effected by the cutting of forests because they are away from forests. But changes in climate effect cities. Calamities like flood and droughts do not spare cities.

(e) Earth:
Earth is the worst effected by deforestation. Its fertile land gets converted into deserts and its temperature rises. Its environment and climate changes.

(f) The Next generation:
The next generation will not be able to see many beautiful and attractive flora and fauna. They will not get a clean and cool environment. They will have to breath poisonous gases and have to live in jungles of concrete.

Question 4.
What will happen if:
(a) we go on cutting trees.
(b) the habitat of an animal is disturbed.
(c) the’top layer of soil is exposed.
Answer:
(a) We go on cutting trees:
If we go on cutting trees, the earth will loose its top fertile soil and get converted to desert. The ecological balance will get disturbed and floods and droughts will become more frequent. Many animals will loose their shelter and there will be a scarcity of things like fruits, paper, etc. we get from forests.

(b) When the habitat of an animal is disturbed, it becomes unprotected and unconserved. It becomes prone to extinction and if not conserved and protected, it will stop to exist anymore on the earth.

(c) When the top layer of the soil is exposed, the humus is lost and fertile soil gets converted into dry sand particles. It is called desertification.

Question 5.
Answer in brief:
(а) Why should we conserve biodiversity?
(b) Protected forests are also not completely safe for wild animals. Why?
(c) Some tribes depend on the jungle. How?
(d) What are the causes and consequences of deforestation?
(e) What is Red Data Book?
(f) What do you understand by the term migration?
Answer:
(a) We should conserve biodiversity to save it from becoming extinct.

(b) Protected forests are also not completely safe for wild animals because the poachers have found access in these areas an,d still kill the wild animals inside these protected areas.

(c) Some tribes are totally dependent on forests for their food, shelter, clothes and other requirements.

(d) Causes of the deforestation are growing urbanization and industrialization. Consequences are the desertification and natural calamities. It has also rendered many species of plants and animals unprotected and unconserved.

(e) Red Data Book is the record book and source book of all the endangered animals and plants. Different record books are maintained for endangered animals and endangered plants.

(f) The term migration means the phenomenon of periodical movement of a species of brids from its owu habitat to some other habitat due to changes in climate. It is for the purpose of breeding and other specific purposes.

Question 6.
In order to meet the ever- increasing demand in factories and for shelter, trees are being continually cut. Is it justified to cut trees for such projects? Discuss this in your class and prepare a brief report.
Answer:
It is not justified to cut forests for any project. We not only cut forests, we snatch away shelters from many plants, animals and birds. They also disturb the ecological balances and cause many natural calamities. So, we should preserve and protect our forests.

Question 7.
How can you contribute to the maintenance of green wealth of your locality? Make a list of actions to be taken byyou.
Answer:
We can grow new plants in our locality. Take turns to water them and take care of them. The existing plants should be properly nourished. All the residents should be taught about the coming dangers due to deforestation like global warming etc. They should be encouraged to help in the maintenance of green wealth of our locality.

Question 8.
Explain how deforestation lead to reduced rainfall.
Answer:
Deforestation leads to reduce rainfall because plants are the main agents to maintain the water cycle in the environment. Plants will not absorb water from the soil and will not evaporate water from their leaves to form clouds. If clouds will not be formed then how can we expect rainfall.

Question 9.
Find out about national parks in your state. Identify and show their location on the outlipe map of India.
Answer:
For self attempt.

Question 10.
Why should paper be saved? Prepare a list of the ways by which you can save paper.
Answer:
Paper is manufactured by using, pulps of tree bark. If we will keep on cutting forests indiscriminately, then where will we get pulp from. We should save paper to protect our trees, because paper can be recycled to make- new paper. We should not throw papers here and there. Newspapers, old books, notebooks and other papers should be collected and sold to kabadiwala, so that he can further supply it for recycling.

Question 11.
Complete the word puzzle:
Down .
1. Species on the verge of extinction.
2. A book carrying information about endangered species.
5. Consequence of deforestation.
Across
1. Species which have vanished.
3. Species found only in a particular habitat.
4. Variety and variability of a plant, animal and microorganisms.

Answer:

Extended Learning – Activities And Projects

1. Plant at least five different plants in your locality during this academic year and ensure their maintenance till they grow.
Answer:
For self attempt.

2. Promise yourself that this year you will gift at least 5 plants to your friends and relatives on their achievements, or on occasions like birthdays. Ask your friends to take proper care of these plants and encourage them to gift plants to their friends on such occasions. At the end of the year count the plants that have been gifted through this chain.
Answer:
For self attempt.

3. It is justified to prevent tribals from staying in the core area of the forest? Discuss the matter in your class and note down the points for and against the motion in your notebook.
Answer:
It is not justifiable in my Qpinin to prevent triabls from the core area of a forest. It is their natural habitat. They are not any threats to animals and plants as their life is centred around plants and animals. They don’t destroy forest or kill animals unnecessarily. Forest for them is an important as for other animals and plants.

4. Study the biodiversity of a park nearby. Prepare a detailed report with photographs and sketches of the flora and fauna.
Answer:
For self attempt.

5. Make a list of the new information you have gathered from this chapter. Which information did you find the most interesting and why?
Answer:
(i) We have learnt how deforestation is destoryed biodiversity.
(ii) We have learnt about the actual meaning ofbiodiversity.
(iii) We have also gathered new information about extinct and endangerous animals.
(iv) We did not know anything about Red Data Book-but know we have learnt about it through this lesson.

6. Make a list of various uses of papers. Obseve currency notes carefully. Do you find any difference between a currency paper and paper of your notebook? Find out where currency paper is made.
Answer:
Paper is very useful for us.
(i) Our book and notebooks are all made up of paper.
(ii) Most of our currency is made up of paper.
(iii) All legal information and other important information are encoded on papers.
(iv) Paper is used to make bags, containers, package materials, etc. The paper used to make currency is stiffer than the normal paper and is transparent to some extent.

7. Karnataka Government had launched “Project Elephant” to save Asian elephants in the state. Find out about this and other such campaigns launched to protect threatened species.
Answer:
For self attempt.

Activities

Activity No. 7.1

Add more causes of deforestation to your list and classify them into natural and man-made.
Answer:
Natural causes of deforestation:
(i) lightning fires.

Man-made causes of deforestation:
(i) animal grazing.
(ii) Wood for fuel making houses.
(iii) Wood for manufacuring of paper.

Activity No. 7.2

Animal life is also affected by deforestation. How? List the points and discuss them in your class. ,
Answer:
(i) Animals loose their shelter as trees are out.
(ii) There is shortage of food for animals due to deforestation.
(iii) Animals become easy prey to hunters and bigger animals.
(iv) Food chains are disturbed.
(v) Animals have to bear the bad effects of natural calamities.

Activity No. 7.4

List the factors disturbing the biodiversity of your area. Some of these factors and human activities may disturb the biodiversity unknowingly. List these . human activities. How can these be checked? Discuss in your class and write a brief report in or notebook.
Answer:
Main factor affecting biodiversity of an area is cutting of trees and using the forest land for construction and industrialization. Excessive rains or droughts also offer the biodiversity of an area. Certain human activities which give rise to polluting end products also disturb the biodiversity unknowningly. When plants and animals do get clean environment they either fall ill or die, thus disturbance in biodiversity.

Activity No. 7.7

Visit a nearby zoo. Observe the conditions provided to the animals. Were they suitable for the animals? Can animals live in artificial setting instead of their natural habitats? In your opinion, will the animals be confortable in a zoo or in their natural habitat?
Answer:
Conditions provided in a zoo can never be compared with the natural habitat. The condition in a zoo are not exactly suitable for animals, although it is tried best to provide best living conditions to the animals in a zoo. But in my opinion animals be most comfortable in their natural habitat.

HBSE 8th Class Science Conservation of Plants and Animals Important Questions and Answers

Very Short Answer Type Questions

Question 1.
What is cutting of forests called?
Answer:
Deforestations

Question 2.
Write any one cause of deforestation.
Answer:
Industrialization.

Question 3.
Name any one natural cause of deforestation.
Answer:
Forest fires.

Question 4.
Write any one consequence of deforestation.
Answer:
Increasing temperature of earth.

Question 5.
What is the process of conversion qf fertile soil into sand called?
Answer:
Desertification.

Question 6.
What are places where wild animals are protected called?
Answer:
Wildlife sanctuary.

Question 7.
What is the part of earth, which supports the biodiversity called?
Answer:
Biosphere reserve.

Question 8.
Name two wildlife sanctuaries hosted by Panchmarhi biosphere reserve.
Answer:
Bori and Panchmarhi.

Question 9.
What do you mean by Flora?
Answer:
All plants found in a particular area.

Question 10.
What do you mean by Fauna?
Answer:
All animals in a particular area.

Question 11.
What are species found only in a restricted area called?
Answer:
Endemic species.

Question 12.
Name any fauna of Panchmarhi Biosphere,reserve.
Answer:
Bison.

Question 13.
Name any three endangered species protected in our wildlife sanctuaries.
Answer:
Black buck, white eyed buck, golden cat.

Question 14.
What do National Parks preserve?
Answer:
Flora, fauna, landscape and historical objects.

Question 15.
Which is the first Reserve Forest of India?
Answer:
Satpura National Park.

Question 16.
Which prehistoric evidences of human life are found in Satpura National Park?
Answer:
Rock shelters of primitive humans.

Question 17.
When was Project Tiger launched?
Answer:
1st April, 1973.

Question 18.
What are the animals facing the danger of extinction are called?
Answer:
Endangered animals.

Question 19.
Name any one extinct animal.
Answer:
Dinosaurs.

Question 20.
Name the record book having records of all endangered animals and plants.
Answer:
Red Data Book.

Question 21.
Name some migratory birds.
Answer:
Surkhab, Bar Headed Goose, Great Cormorant.

Question 22.
How many times a paper can be recycled?
Answer:
5-7 times.

Question 23.
What do we call the restocking the plants by growing new plants?
Answer:
Reforestation.

Question 24.
What is plantation of new plants called?
Answer:
Afforestation.

Question 25.
What is the revised Forest Policy of 1952 called?
Answer:
Forest Act, 1980.

Short Answer Type Questions

Question 1.
What do you mean by deforestation?
Answer:
Indiscriminate cutting of forests for urbanization and industrialization is called deforestation. In simple words, deforestation means to clear the forests and use the land for other purposes.

Question 2.
Write some natural causes of deforestation.
Answer:
Natural causes of deforestation are those causes which are not initiated by human beings. Natural phenomenon like lightening on forests cause major forest fires, which can bum a large area of forests. Forest fires due to intense heat cause spontaneous combustion and bums a vast area of forest. Similarly, floods and severe droughts also cause damage to forests.

Question 3.
Write a few consequences of deforestation.
Answer:
Deforestation. has dangerous consequences which prove fatal for wildlife and human life. It gives rise to severe droughts and floods. It converts the fertile land into desert. It increases the temperature of the earth which causes melting of polar ice and glaciers. Many important species of plants, animals and birds become extinct and other stands at the verge of extinction.

Question 4.
How deforestation reduces rainfall?
Answer:
Deforestation disturbs the water cycle and reduces the rainfall. Increased amount of carbondioxide in environment increases the temperature of the earth. Which means there is less amount of water left on the earth. This reduces the evaporation of the water to form clouds thus reduced rainfall.

Question 5.
What do you mean by biodiversity?
Answer:
Biological diversity means the variety of living things existing on earth and their inter-relationship, as well as their relationship with the environment. In other words, variety of plants, animals and microorganisms generally found in an area is called its biodiversity.

Question 6.
What do you mean by endemic species?
Answer:
Species of animals and plants which are only found in a particular geographical area is called endemic species. These plants and animals cannot be found in any other geographical area e.g., wild mango arid gaint squirrel is endemic species of Panchmarhi.

Question 7.
What do you mean by wildlife sanctuaries?
Answer:
Wildlife sanctuaries are the protected areas where wild animals are protected and conserved. The wild animals are provided with their natural habitat. Their poaching and capturing is strictly prohibited m these protected areas.

Question 8.
What is a National Park?
Answer:
National Park is the protected vast area which conserves animals, plants, landscapes and even the historical objects. They are very large areas and can even protect whole sets of ecosystems in them. India has many such National Parks like Satpura National Park, Kaziranga National Park, etc.

Question 9.
What are the endangered and extinct animals?
Answer:
Endangered animals are those which are facing the danger to their existence. They are threatened to stop existing on the earth, if not saved. The extinct animals are those which do not exist any more on the earth e.g. Dinosaurs.

Question 10.
What is ecosystem?
Answer:
An ecosystem comprises of all the plants, animals, microorganisms in a particular area alongwith its non-living components like climate, soil, river, deltas etc.

Question 11.
What do you know about Project Tiger?
Answer:
Project Tiger was launched by Gqf*rtnment of India on 1st April, 1973 to enusre the maintenance of a viable populati on of tigers in our country. Tigers are one of the endangered species, so to preserve it Project Tiger was launched.

Question 12.
Why do birds migrate?
Answer:
Birds migrate from one place to another due to change in climate and for specific purposes like breeding etc. When weather in their natural habitat becomes cold they migrate to other lands covering long distances to lay eggs.

Question 13.
How does recycling of paper help preserving trees?
Answer:
Paper is made from the bark of trees. If used paper is recycled to make new papers, it means we do not have to cut more trees. So, recycling paper means protecting trees.

Question 14.
What do you mean by Habitat?
Answer:
Each species can live in particular environment according to their characteristics. So, the natural surroundings of a plant or animal species where they can grow, reproduce and live comfortably are called habitats, e.g. a lion can live in jungle, but not in a city. So jungle is the habitat of the lion.

Long Answer Type Questions

Question 1.
What is Deforestation? Write its causes.
Answer:
Deforestation means indiscriminate cutting of trees in forest. Forest lands are cleared to be used for urbanisation and industrialization.
Following are different causes of deforestation:
(i) Forest land is used for urbanization. As population is growing, so is growing the need for houses. So more and more land is required.
(ii) With growing population, industries are also growing. So the cleared land is used to set-up factories and industries.
(iii) Wood of forest is used for making furniture, doors, windows of buildings etc.
(iv) Wood is cut to use as fuel for cooking.
(v) Some natural causes like forest fires etc. also cause destruction of forests.

Question 2.
What are the consequences of deforestation? Explain.
Answer:
Deforestation has dire consequences. Following are the consequences of deforestation:
(i) Deforestation snatches away the natural habitat of many animals, plants and birds. It puts many species in endangered zone and many get extinct.
(ii) Deforestation causes natural calamities like floods, drought etc.
(iii) Reduced rainfall and increase in earth’s temperature has caused problems like Global warming.
(iv) Increased amount of carbondioxide and other gases pollute environment.
(v) Oxygen level is decreased as well as the water level.
(vi) Fertile top layer of soil gets converted into desert.

Question 3.
What is done for the conservation of wildlife?
Answer:
Various measures are taken to conserve wildlife. Reserved and protected areas like Biosphere reserve, Wildlife sanctuaries and National parks are formed.

Biosphere Reserves are the areas which support biodiversity and culture of the reserved area. Biosphere Reserve is a vast area which contains many other protected areas.

Wildlife Sanctuaries are the areas where wild animals are conserved and protected. It is the area which is restricted and activities like killing of animals and capturing of animals are strictly prohibited.

National Parks: National Parks are meant to protect and preserve flora, fauna, landscapes and historical objects of an area. They not only protect the living organisms, but also the non-living things of that particular area.

Question 4.
What do you mean by Endemic Species? Write about any three species endemic to India.
Answer:
Species of animals and plants comfined to certain specific geographical areas are called endemic species. Following are the three species of animals endemic to India.
(i) Lion-tailed macaque:
This animal got his name from its tail which is 25 cm in length and has a tuft at the end like that of lion’s which is black in colour. It is endemic to south-west India an is one of the most threatened primates.

(ii) Asiatic lion:
Asiatic lion is now endemic to Gir National Patk only as it is believed that the last remnants of this species are found in Gir National Park in Gujarat only.

(iii) Nilgiri ibex:
These stocky goats possessing short coarse fur and a bristly main are endemic to Nilgiri Hills and the Southern postion of the Western Ghats range in Tamil Nadu and Kerela. It is actually called Nilgiri Thar and Nilgiri ibex is its local name.

Question 5.
What is migration and why animals migrate?
Answer:
Movements of animals in large number from one place to another place to escape unfavourable conditions is called migration. Animals migrate for specific purposes. When the purpose is solved, they usually come back to their endemic area.

Migration can be due to unfavourable environmental conditions, eg. The Arctic Tern migrate to Antarctic to spend its winlers. Some birds of colder regions migrate to Asiatic countries during winters. This type of migration is called seasonal migration which occur in many species of insects, birds, marine mammals and herbivorous mammals.

Migration is also done for better food or water availability in other regions due to temperature and other climatic conditions.
Some species of animals and birds also migrate for the purpose of reproduction e.g. fresh watereeds go to saltwaters from freshwater to lay eggs.

Question 6.
What is poaching? How is it done by anti social elements and for what purpose?
Answer:
Illegal hunting of animals is called poaching. Anti-social element some time create a nexus with the forest staff for poaching; They hunt the animals for selling their skin, horn, fur and hides.

All valuable parts of these animals are used for various purposes and are sold at very high prices.
Uses for ornaments: The bones and other parts like trunks of elephants etc. are used to make ornaments.
Uses in medicines: The horns and bones of some animals like rhinoceros and tigers are used to prepare some traditional medicine specially in Asian countries.
For wall hanging and clothings: The skin, fur and hides are used for the clothing. Mufflers, coats, jackets, skirts etc. are made using leather and fur of the animals like cats, minks, bears foe fur, skin of alligators and snakes and deer and cattle are killed for leather.

Question 7.
Write a short note op migratory birds.
Answer:
Migratory birds are those birds which migrate from their natural habitat to far off areas for breeding. When the natural habitat o.f these birds become very cold, they fly off to distant lands to lay eggs, as climate there is suitable for their breding. They always fly to a specific area every year at a specific period. They migrate in groups to escape the inhospitable climate of their natural habitat.

Birds like Surkhab fly to India from Malyasia. Other birds like Bar Headed Goose, Great Cormorant etc. are also migratory birds.

Question 8.
Recycling of paper helps to protect forest and environment. Explain.
Answer:
Paper is made from trees. Innumerable trees are cut to manufacture paper. If we recycle used paper, we will not have to cut trees to manufacture new paper. Each paper can be recycled 5-7 times and can be used. If we do not throw paper here or there and collect it to be sold to the Kabadiwala, we sire saving our green wealth. It will also save the chemicals used to prepare paper and also the energy used for preparing it. The wastage mid garbage produced during this process will also be reduced and environment will remain clean.

Question 9.
How can we save CHIT green wealth?
Answer:
Our forests are our wealth. We should not destory them but conserve them. To conserve our forests, first of all we should stop cutting them. We should plant as many plants as we cut, so that the number of trees remain unchanged. People should be made aware of the bad effects of deforestation and they should be made familiar with the advantages of the trees for us. Community plantation programmes should be encouraged. Students should be encouraged to plant one plant every year. Plantation of trees is not sufficient. They need proper look after too. So, the tree we plant, should be nourished and taken care of.

Conservation of Plants and Animals Class 8 HBSE Notes

1. A vast variety of plants and animals exist on earth.
2. Deforestation is a threat to the survival of these plants and animals as major varieties of plants and animals are present in forests.
3. Indiscriminate cutting of forests is called deforestation. Land cleared by deforestation is used for other purposes too.
4. Trees cut from these forests are used to make furnitures, papers, houses and is also used as . fuel.
5. Deforestation causes floods, droughts, infertility of soil and many other natural calamities.
6. Soil looses humous due to deforestation and becomes sand, thus deforestation converts a fertile land into a desert and it is called desertification.
7. We should conserve our forests by planting more and more trees which is called afforestation. For conservation of animals; wildlife sancturies and hational parks are formed. They give shelter to our wildlife and help to preserve our endangered species of plants and animals.
8. Variety pf life existing on earth and their inter-relation is called biodiversity. In other words biodiversity is variety of plants and animals and microorganisms generally found in a specific area. Such life is supported by the area called Biosphere.
9. Species ofplants and animals exclusively found in a restricted area are called Endemic species. They are not found in any other geographical area.
10. These species which are at the verge of extinction are called endangered species.
11. Red Data Book contains a record of the endangered species.

Haryana State Board HBSE 8th Class Science Solutions Chapter 6 Combustion and Flame Textbook Exercise Questions and Answers.

Haryana Board 8th Class Science Solutions Chapter 6 Combustion and Flame

HBSE 8th Class Science Combustion and Flame Textbook Questions and Answers

Question 1.
List conditions under which combustion can take place.
Answer:
Following conditions are necessary for combustion:
(i) The substance should be combustible.
(ii) It should have low ignition temperature.
(iii) There should be proper supply of air.

Question 2.
Fill in the blanks:
(a) Burning of wood and coal causes …………. of air.
(b) A liquid fuel, used in homes is …………. .
(c) Fuel must be heated to its before it …………. starts burning.
(d) Fire produced by oil cannot be controlled by …………. .
Answer:
(a) pollution
(b) Kerosene
(c) ignition temperature
(d) water.

Question 3.
Explain how the use of CNG in automobiles has reduced pollution in our cities.
Answer:
CNG has replaced petrol and diesel as fuel in automobiles because petrol and diesel produced a lot of unbumt carbon particles and emitted carbondioxide and nitrogen oxides and sulphur dioxide. These all gases are poisonous gases and cause various environmental hazards. But CNG is safe because it produces these substances in very small amounts thus reducing pollution in cities.

Question 4.
Compare LPG and wood as fuels.
Answer:

Question 5.
Give reasons:
(a) Water is not used to control the fire involving electrical equipment.
(b) LPG is a better domestic fuel than wood.
(c) Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not. .
Answer:
(a) Water is a conductor of electricity, so it can easily conduct electric current and causes danger of electric shocks.
(b) LPG is a better domestic fuel than wood because unlike wood it does not produce smoke and is comparatively easy to transport.
(c) Paper by itself catches fire easily because it has low ignition temperature but when wrapped around an aluminium pipe its

Question 6.
Make a labelled diagram of a candle flame.
Answer:

Different Zones of Candle flame

Observe the foaming reaction. What happens to the candles? Why? In what order?

Answer:
The candles get extinguished. The smaller candle with get extinguisher first because thfe supply of oxygen is cut of due to foam; The smaller candle will come in effect of foam earlier than the longer one and thus stop burning prior to the longer candle.

Activity

Combustible and Non-combustible Substances

HBSE 8th Class Science Combustion and Flame Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Why do we need fuel?
Answer:
We need fuel to generate energy.

Question 2.
Name any three fuels.
Answer:
Coal, wood, LPG, kerosene, petrol.

Question 3.
What is produced during combustion?
Answer:
Heat and light.

Question 4.
In what forms light is given during combustion?
Answer:
In form of flame or glow.

Question 5.
How does charcoal burn?
Answer:
It burns with glow.

Question 6.
How does a candle burn?
Answer:
It burns with flame.

Question 7.
Name two objects which burn without flame.
Answer:
Coal and charcoal.

Question 8.
Name two objects which burn with flame.
Answer:
LPG and candle.

Question 9.
Name any three combustible substances.
Answer:
Wood, coal, LPG.

Question 10.
What is necessary for substances to burn?
Answer:
Air.

Question 11.
How does sun produces heat although it does not have air?
Answer:
It produces heat by nuclear reactions.

Question 12.
In addition to air, what else is a necessary condition for a substance to burn?
Answer:
Low ignition temperature.

Question 13.
What are the substances with very low ignition temperature called?
Answer:
Inflammable substances.

Question 14.
Name some inflammable substances.
Answer:
Alcohol, petrol, LPG., etc.

Question 15.
What substances are used to extinguish fire?
Answer:
Water, sand, fire extinguishers.

Question 16.
What should we use to extinguish fire in case of electric short circuit?
Answer:
Sand or soil.

Question 17.
Name different types of fire extinguishers.
Answer:
(i) Soda-acid fire extinguishers
(ii) Hydrocarbon fire extinguisher.

Question 18.
Name different types of combustions.
Answer:
Rapid combustion, Spontaneous combustion and explosions.

Question 19.
Name different zones of a flame.
Answer:
Outer non-luminous zone, luminous zone and dark zone.

Question 20.
Which zone of a flame has highest temperature?
Answer:
Non-luminous zone.

Question 21.
Name two properties of an ideal fuel.
Answer:
High calorific value and low cost.

Question 22.
Is there any ideal fuel?
Answer:
No ideal fuel exist.

Question 23.
What is smoke?
Answer:
Smoke is unburnt carbon particles.

Question 24.
Which diseases do incomplete combustion cause?
Answer:
Respiratory and skin diseases.

Question 25.
What is supposed to be the cause of global warming?
Answer:
Increasing amount of carbon dioxide.

Question 26.
What is the rise in temperature of the environment of earth called?
Answer:
Global warming.

Question 27.
What does global warming lead to?
Answer:
Global warming leads to melting of polar glaciers.

Question 28.
Which chemicals give rise to acid rains?
Answer:
Sulphur dioxide and nitrogen oxides.

Question 29.
Which fuel is being used in automobiles in place of petrol and diesel?
Answer:
CNG.

Question 30.
Does CNG produce poisonous substances on burning?
Answer:
In very small amounts.

Short Answer Type Questions

Question 1.
Define combustion.
Answer:
A chemical process in which a substance reacts with oxygen to give off heat is called combustion. Burning of substances to get heat is called combustion.

Question 2.
What is produced when a combustible substance burns?
Answer:
When a combustible substance burns it produces heat and light. Light is in the form of glow or flame. Some combustible substances do not
burn in a flame, they simply glow.

Question 3.
How will you prove that air is necessary for burning?
Answer:
Burn a candle. Now put a beaker inverted on it. You will see the flame will flicker and then it will extinguish. As the inverted beaker has cut off the oxygen supply, the flame is extinguished. This proves air is necessary for burning.

Question 4.
What do you mean by ignition temperature?
Answer:
The lowest temperature at which a substance catches fire is called its ignition temperature. This is the temperature which has to be there, if the substance has to burn, below it the object will not catch fire.

Question 5.
What are inflammable substances?
Answer:
Some substances have very low ignition temperature and they catch fire very easily. Suflj substances are called inflammable substances. Petrol, alcohol, LPG etc. are the inflammable substances.

Question 6.
Write three things necessary for fire to produce?
Answer:
Three conditions necessary to produce fire are following:
(i) Presence of oxygen i.e, air.
(ii) Ignition temperature.
(iii) Presence of combustible substances.

Question 7.
What can be done to put the fire off?
Answer:
To put off the fire one of the conditions necessary for burning should be removed or controlled. If we cut off the supply of air, fire will be extinguished or we can bring the ignition temperature down to blow off the fire.

Question 8.
Why can’t water control the fire due to oils?
Answer:
Water cannot put off fire due to oils because water is lighter than oil. It settles down the oil particles and cannot bring the ignition temperature of the substance down, thus cannot control the fire.

Question 9.
What should be done to control fire due to oils?
Answer:
In case of fire due to oils, water is not useful as it is lighter than oil and settles down below the oil particles. In such cases, sand or soil should be used. They cut off the supply of air to the fire and it is put off.

Question 10.
How does carbondioxide help in putting off fire?
Answer:
Carbondioxide covers the surface of the burning substance and does not allow the oxygen to reach the substance. In absence of oxygen the fire gets put off.

Question 11.
What is rapid combustion?
Answer:
When gases bum quickly to produce heat and light it is called rapid combustion. This process takes place rapidly and takes less time.

Question 12.
What is spontaneous combustion?
Answer:
When an object catches fire on its own without any apparant cause, it is called spontaneous combustion. In this type of combustion the object suddenly bursts into flame. For example, phosphorus catches fire in air.

Question 13.
Write the properties of an ideal fuel.
Answer:
An ideal fuel has following qualities:
(i) It has high calorific value.
(ii) It has low ignition temperature.
(iii) It is cheap and easily available.
(iv) It can be easily transported.

Question 14.
Write some harmful effects of burning fuel.
Answer:
Burning fuel can cause following ill effects:
(i) Unbumt carbon particles of these fuels can cause respiratory and skin diseases.
(ii) Smoke emitted by these fuels cause pollution and many diseases.
(iii) Poisonous gases like carbondioxide, carbonmonoxide and sulphurdioxide etc. pollute the air.

Long Answer Type Questions

Question 1.
Explain the conditions necessary for cpmbustion.
Answer:
Combustion is burning of substances. For combustion of substances following conditions are necessary: .
(i) Air:
Substances only bum in sufficient supply of air i.e. oxygen. If the supply of air is hindered the object will not bum. In case of a burning object, if air is hindered, it will stop burning. This fact is used in extinguishing the fires.

(ii) Ignition Temperature:
Ignition temperature is the minimum temperature at which a substance starts burning. Those substances which have low ignition temperature can bum easily, while those which have high ignition temperature need more heating and burn late.

(iii) Presence of combustible substance:
If a substance is not combustible, it will not catch fire at all, so to produce fire it is necessary to have a combustible substance.

Question 2.
Describe the working of soda-acid fire extinguisher.
Answer:
Soda-acid fire extinguisher is based on the cooling the temperature of the burning object. This type of fire extinguisher contains sulphuric acid and sodium bicarbonate. When the extinguisher becomes functional, the sulphuric acid reacts with sodium bicarbonate to produce carbondioxide. Carbondioxide when released, cuts off the supply of oxygen and water is released to bring down the ignition temperature of the burning object. In this way fire is controlled.

Question 3.
What are different types of combustion?
Answer:
Combustion is of three types:
(i) Rapid combustion: When gases bum rapidly to produce heat and light it is called rapid combustion.
(ii) Spontaneous combustion: When any material like phosphorus bums on its own without any apparant cause, it is called spontaneous combustion.

(iii) Explosion:
When combustion takes place with sudden release of heat and light and a large amount of gas in form of bang, it is called explosion as in case of crackers and bombs.

Question 4.
Explain various harmful effects of burning fuels.
Answer:
Fuels are very useful for us. But there are certain disadvantages of burning fuels.
(i) Fuels like wood, coal, petroleum etc. which are carbon fuels generally release unbumt carbon particles which are quite harmful. They cause various respiratory and skin diseases.

(ii) In most of the cases carbondioxide is released during burning of fuels. This carbondioxide is released in environment. Carbondioxide is an identified cause of increasing temperature of the earth, which is called global warming.

(iii) Incomplete combustion of fuels release many poisonous gases like carbonmonoxide. in the environment. These poisonous gases create air pollution, such air if inhaled can be fatal.

(iv) Combustion of coal and diesel generates sulphurdioxide. It is a corrosive gas and it causes suffocation.

(v) Burning of petrol releases nitrogen oxides. These oxides of nitrogen and sulphurdioxide combine with rain water to cause acid rains.

Question 5.
Describe the various zones of a candle flame.
Answer:
The candle flame has three different zones. These zones can be distinguished on the basis of their colour.
(i) The outer zone:
It is blue in colour and it has very high temperature. It is the hottest zone of the flame. In this zones the wax vapours bum completely due to availability of enough oxygen, in turn carbondioxide and water vapours are produced.

(ii) The middle zone:
In this zone the flame bums with yellow colour and the wax vapours start burning here. The yellowish colour of the flame is due to the burning of carbon particles. These carbon particles are produced due te incomplete burning of the wax vapours due to less suppy of oxygen. Carbonmonoxide is also produced along the carbon particles. This zone is luminious but with low temperature.

(iii) The inner zone:
This zone appears black in colour as no combustion of wax vapour take place in this zone due to no supply of oxygen in this zone. It is the coolest zone of the flame having unbumt wax vapour.

Combustion and Flame Class 8 HBSE Notes

1. All substances which catch fire/bum in air are called combustible substances.
2. Wood, paper, petrol, L.P.G., charcoal etc. are some examples of combustible substances.
3. During combustion heat and light is emitted. The light is emitted in the form of flame.
4. All combustible substances do not burn with flame, for example coal does not bum with flame, while wood, paper, candle, L.P.G., etc. bum with a flame.
5. There are two main things required by a substance to become combustible. These are: low ignition temperature and air.
6. Ignition temperature is the lowest temperature at which a combustible substance can easily catch fire. Inflammable substances have very low ignition temperature.
7. If any of the above condition is removed,’fire can be extinguished. Either we bring ignition temperature below minimum or we cut off the supply of air.
8. Water, sand are mostly used to bring fire under control.
9. There are three main zones of a flame. The outermost zone has the highest temperature while the inner zone has unbumt carbon particles.
10. Fuel is a substance which is used to give energy and heat. Ideal fuel has low ignition temperature and readily available. It is cheap and has high calorific value. It is free from pollution.
11. But no fuel is an ideal fuel.
12. Fuels are not same in their efficiency and cost.
13. Calorific value of fuels is expressed in units of kilojouls per kg.
14. Combustion of an inflammable substance should be complete because incomplete combustion produce unburnt carbon particle which can cause serious environmental hazards like acid rain, global warming and poisonous gases causing dangerous diseases in living beings.
15. Global warming the most alarming environmental problem is being created due to increased amount of carbondioxide in air.
16. Acidic rain is caused due to the oxides of nitrogen and sulphur released in environment due to burning of coal, diesel and petrol.

Haryana State Board HBSE 8th Class Science Solutions Chapter 5 Coal and Petroleum Textbook Exercise Questions and Answers.

Haryana Board 8th Class Science Solutions Chapter 5 Coal and Petroleum

HBSE 8th Class Science Coal and Petroleum Textbook Questions and Answers

Question 1.
What are the advantages of using GNG and LPG as fuels?
Answer:
CNG – Compressed Natural Gas and LPG – Liquefied Petroleum Gas are easy to handle and use. It is easy to transport them and moreover they are free from any types of pollution on usage.

Question 2.
Name the petroleum product used for surfacing of roads?
Answer:
Bitumen or coaltar is used for surfacing of roads.

Question 3.
Describe how coal is formed from dead vegetation. What is this process called?
Answer:
Millions of years ago many dead animals and plants got trapped under the layers of earth. They got compressed and the temperature under the earth started raising due to hfgh pressure and temperature, the dead plants and animals got converted into coal. This process is called carbonization.

Question 4.
Fill in the blanks:
(а) Fossil fuels are ………. , …………. and …………. .
(b) On destructive distillation of coal …………. , …………. and …………. are obtained.
(c) Process of separation of different constituents from petroleum is called …………. .
(d) Least polluting fuel for vehicle is …………. .
Answer:
(a) coal, petroleum and natural gas
(b) coke, coal-tar and coal gas
(c) refining
(d) CNG.

Question 5.
Tick True/Ffdse against the following statements:
(а) Fossil fuels can be made in the laboratory. (T/F)
(b) CNG is more polluting fuel than petrol. (T/F)
(c) Coke is almost pure form of carbon. (T/F)
(d) Coal-tar is a mixture of various substances. (T/F)
(e) Kerosene is not a fossil fuel. (T/F)
Answer:
(a) False
(b) False
(c) True
(d) True
(e) False.

Question 6.
Explain why fossil fuels are exhaustible natural resources?
Answer:
Fossil fuels are exhaustible natural resources because they are made by the decomposition of the dead remains of living organisms. It is present in limited quantity beneath the earth, thus it will come to an end by human usage.

Question 7.
Describe characteristics and uses of coke.
Answer:
Coke is obtained by burning of coal in absence of oxygen. The process is called destructive distillation. Coke is used to manufacture steel. Coke is used in the extraction of many metals.

Question 8.
Explain the process of formation of petroleum.
Answer:
Petroleum is a fossil fuel. It is formed beneath the earth by decomposition of the dead bodies of the living organisms hurried beneath the earth. Due to some natural calamities like earthquake or volcano, innumerable living organisms (Plants and animals) got hurried beneath the earth. Due to heat and pressure, they started getting decomposed and got converted into liquid and gas form. In this way Petroleum oil and petroleum gas are formed.

Question 9.
The following Table shows the total power shortage in India from 1991-1997. Show the data in the form of a graph. Plot shortage percentage for the year on the Y- axis and the year on the X-axis.

Answer:

Extended Learning – Activities And Projects

Get an outline map of India. Mark the places in the map where coal, petroleum and natural gas are found. Show the places where petroleum refineries are situated.
Answer:
For self attempt.

2. Choose any five families of your neighbourhood. Enquire whether their energy consumption (coal, gas, electricity, petrol, kerosene) has increased or decreased in the last five years. Enquire also about the measures they adopt to conserve energy.
Answer:
For self attempt.

3. Find out the location of major thermal power plants in India. What could be the reasonsi for their being located at those places?
For more information visit:

• www.energyquest.ca.gov/story/chapter08.html
• en.wikipedia.org/ wiki/ Non-renewable_resources
• http://www.eiadoe.gov/kids/energyfacts/ sources/non-renewable/oil.html

Answer:
For self attempt.

HBSE 8th Class Science Coal and Petroleum Important Questions and Answers

Very Short Answer Type Questions

Question 1.
From where we find all the materials we use in our daily life?
Answer:
We get all these materials from natural resources as well as from man-made resources.

Question 2.
How many kinds of natural resources are there on the basis of availability of materials?
Answer:
On the basis of availability of materials, natural resources are oftwo types: Inexhaustible and exhaustible.

Question 3.
What are inexhaustible natural resources?
Answer:
Inexhaustible natural resources are those resources which cannot be finished by human activities.

Question 4.
Give two examples Pf Inexhaustible natural resources.
Answer:
Sunlight and air.

Question 5.
What are exhaustible natural resources?
Answer:
Exhaustible natural resources are those resources which are present in limited quantity and can get finished by hurt!an activities.

Question 6.
Give two examples of exhaustible natural resources.
Answer:
Petroleum, wildlife.

Question 7.
What are fossil fuels?
Answer:
Those fuels which got formed by the decomposition of the dead remains of living organisms for a long period of time are called fossil fuels.

Question 8.
Give tWo examples .of fossil fuel.
Answer:
Petroleum, coal.

Question 9.
What is coal?
Answer:
Coal is an exhaustible natural fossil fuel which is as hard as stone and is of black colour.

Question 10.
Write any two uses of coal.
Answer:
Coal is used as fuel to cook food. Coal is used as fuel to run trains.

Question 11.
What does coal mainly consist of?
Answer:
Coal mainly consists of carbon.

Question 12.
What is cabonization?
Answer:
Slow process of conversion of dead remains of living organisms into coal is called carbonization.

Question 13.
Which gas is released when coal ishumt?
Answer:
Carbondioxide.

Question 14.
To which process coal is put to get some useful products?
Answer:
Destructive distillation.

Question 15.
What is destructive distillation?
Answer:
Burning of coal in absence of oxygen to get coke and; other useful products is called destructive distillation.

Question 16.
What is the pure form of carbon?
Answer:
Coke.

Question 17.
What is coal-tar?
Answer:
Coal-tar is a black liquid that is produced during destructive distillation of coal.

Question 18.
Which petroleum product is used for metalling the roads in place of coal-tar?
Answer:
Bitumen.

Question 19.
What is used as fuel in light vehicles?
Answer:
Petrol.

Question 20.
What is used as fuel in heavy vehicles?
Answer:
Diesel.

Question 21.
Where was petroleum formed?
Answer:
Petroleum was formed under the sea.

Question 22.
Which conditions under the sea formed petroleum?
Answer:
Absence of air, high temperature and high pressure.

Question 23.
Where was the first oil well digged?
Answer:
Pennsylvania, U.S.A. in year 1859.

Question 24.
Name some places of India where oil is found.
Answer:
Assam, Gujarat, Bombay High, River basins of Godawari and Kaveri.

Question 25.
Which constituents are separated from-petroleum during its refining?
Answer:
Petroleum gas, petrol, diesel, lubricating oil, paraffin wax etc.

Question 26.
What is the full form of L.P.G.?
Answer:
Liquefied Petroleum Gas,

Question 27.
What is the use of L.P.G.?
Answer:
L.P.G. is used as fuel in home and in vehicles.

Question 28.
What is the use of Paraffin wax?
Answer:
Used in ointments, candles, vaseline, etc.

Question 29.
What are petrochemicals?
Answer:
Various useful constituents obtained from petroleum are called petrochemicals.

Question 30.
What is full form of C.N.G.?
Answer:
Compressed Natural Gas.

Question 31.
What are the uses of C.N.G.?
Answer:
C.N.G. is used as pollution free fuel for vehicles and in power generation.

Question 32.
Where in India is C.N.G. found?
Answer:
Tripura, Jaisalmer, Offshore of Mumbai and in Krishna Godawari Delta.

Question 33.
Can coal, petroleum and natural gas be prepared in laboratory?
Answer:
No.

Short Answer Type Questions

Question 1.
In how many types can we classify our resources?
Answer:
We can classify out natural resources in two types:
(i) Man-made resources
(ii) Natural resources.
Natural resources can further be classified in two types on the basis of the availability of resources: Exhaustible and inexhaustible resources.

Question 2.
What do you mean by Inexhaustible natural resources?
Answer:
These are the resources which are present in nature in unlimited amount and can never get finished by human activities. Air, sunlight, soil etc. are examples of inexhaustible natural resources.

Question 3.
What do you mean by exhaustible natural resources?
Answer:
Exhaustible natural resources are those resources which are present in nature in limited amounts and can get finished by human activities. Petroleum, Natural Gas, Coal etc. are exhaustible natural resources.

Question 4.
What do you mean by fossil fuels?
Answer:
Fuels which were formed by the dead remains of the living organisms by process which took thousands of year to complete are called fossil fuels. Petroleum, coal, natural gas are the fossil fuels which got formed under the sea and earth respectively, when they got hurried under the sea and earth.

Question 5.
What is coal and write its uses?
Answer:
Coal is a black stone like substance. It is formed by the dead remains of the living organisms.
(i) Coal is used as fuel to cook food.
(ii) It is used to run trains, as it is burnt to generate steam in engine.
(iii) It is used in thermal power plants to produce electricity.
(iv) Coal is also used as fuel in different industries.

Question 6.
How was coal formed?
Answer:
Millions of years ago dense forests of earth got hurried under the soil due to volcanoes and earthquakes. More deposits of soil compressed the hurried dead bodies. As they became deeper temperature started rising. This started converting dead bodies into coal.

Question 7.
What is coke? How is it useful to us?
Answer:
Coke is a hard porous black substance. It is obtained by destructive distillation of coke. It is almost pure form of carbon.
(i) Coke is used to manufacture steel.
(ii) It is used in extraction of many metals.

Question 8.
What is coal-tar? How is it useful to us?
Answer:
Black liquid obtained during destructive distillation of coal is coal-tar. It is thick and smells unpleasant. It is a mixture of hundreds of substances. Substances obtained from coal-tar are used to manufacture synthetic dyes, drugs, explosives, perfumes, plastics, paints, roofing materials, photographic materials, etc.

Question 9.
What do you mean by petroleum?
Answer:
Petroleum is a fossil fuel obtained from the dead remains of organisms living in sea. Petroleum is a dark oily liquid having unpleasant . odour. It has various useful constituents which are separated from it by process of fractional distillation at petroleum refineries.

Question 10.
How was petroleum lormed?
Answer:
Millions of years ago, sea organisms died and their dead bodies got settled at the bottom of the sea. Slowly they got covered by sand and clay. Absence of air, high temperature and high pressure for years, converted these bodies into petroleum oil and natural gas.

Question 11.
Name any three constituents obtained from refining petroleum and their uses.
Answer:
(i) L.P.G.: It is used as domestic fuel and fuel for vehicles.
(ii) Petrol: It is used as fuel for light vehicles, aviation fuel and used in drycleaning of fabric.
(iii) Kerosene: It is used as fuel for stoves, lamps an d for jet aircrafts.

Question 12.
What is diesel? How is it different from petrol?
Answer:
Diesel is one of the constituents obtained by the refining or fractional distillation of petroleum. It is mainly used as the fuel for vehicles as petrol is used. But it is different from petrol, as it is used as fuel for heavy vehicles like trucks, lories, etc. while petrol is used as fuel in light vehicles like cars, scooters, etc.

Question 13.
What is CNG?
Answer:
GNG is Compressed Natural Gas which is a fossil fuel and is formed along petroleum oil. It is used as the pollution free fuel for transport vehicles. It is more convinient to use as its transportation is easy and it can be directly burnt.

Long Answer Type Questions

Question 1.
Classify various materials we use in our lives.
Answer:
All the materials we use can be broadly classified into two groups:
(a) Natural Resources
(b) Man-made Resources.
(a) Natural resources are those resources which are present in our nature, gifted by God. They can be freely used. Soil, air, sunlight, water, wildlife, etc. are some natural resources.
(b) Man-made resources are those resources which are formed by various efforts of man and are artificial. Plastics, fibres, electricity, etc. are all artificial resources.

On availability of materials natural materials can further be classified as:
(i) Inexhaustible Natural Resources:
Those resources which are present in unlimited quantity and will never get exhausted by human activities. Sunlight, air, soil, etc. are some inexhaustible natural resources.

(ii) Exhaustible Natural Resources:
Those resources which are available in limited amount and will get finished by human activities. Petroleum, coal, wildlife, forests, etc. are some examples of exhaustible natural resources.

Question 2.
What is coal and how was it formed? Explain.
Answer:
Coal is a fossil fuel which is as hard as a stone. It is black in colour and is mainly used as fuel. As coal is a fossil fuel, it was formed by the dead remains of the plants. Millions of years ago vegetation in forests got trapped under soil layers due to earthquakes and volcanic erruptions. More soil layers got deposited on it and it went deeper and deeper beneath the earth.

This raised the temperature and pressure beneath the soil. This initiated the process of burning these dead remains. Slowly all the vegetations got converted into coal which is a rich form of carbon. This whole process is also called carbonization.

Question 3.
How was petroleum formed? What is refining of petroleum?
Answer:
Petroleum is a fossil fuel which got formed by the dead remains of the sea-animals. These animals slowly got trapped under soil and clay and more deposits were formed with time. Due to depth, the temperature and pressure raised and over the years they got converted into petroleum oil. Since oil is lighter than water, it did not get mix with water and got raised to the superficial rocks, which did not allow it to pass through them. To obtain petroleum, we have to dig wells to perforate the top rocks and pump up the petroleum oil.

The petroleum oil we get from these wells is a mixture of variuos other useful substances. Petroleum oil is, thus, refined to separate these useful by-products in petroleum refineries.

Question 4.
Name different constituents of petroleum and write their uses.
Answer:
Following are various constituents of petroleum oil obtained during fractional distillation in oil refineries:
(i) Liquefied Petroleum Gas (L.P.G.): It is primarily used as domestic fuel. Now it is used as fuel in vehicles and industry.
(ii) Petrol: It is a black liquid used as fuel in light vehicles like scooters, cars, etc. It is also used as aviation fuel and used for dry cleaning of fabrics.
(iii) Kerosene: It is used as fuel in stoves, lamps and jet aircrafts.
(iv) Diesel: It is used as fuel for heavy vehicles and in electric generators.
(v) Lubricating oil: It, is used to lubricate metal parts and machines.
(vi) Paraffin wax: It is used in ointments’, vaselines and in candles.
(vii) Bitumen: It is used in paints and is used in road-surfacing in place of coal-tar.

Question 5.
Write a note on Natural Gas.
Answer:
Natural gas is one of the most important forms of fossil fuel. The reason being that it is very easy to transport through pipes and cylinders. Natural gas is extracted and stored under very high pressure. As it is kept compressed under high pressure, it is called .

Compressed Natural Gas or CNG. The great advantage of CNG is that it does not cause pollution on usage as in case of other petrochemicals like petrol and diesel. Secondly, it can be directly burnt in homes and factories for cooking and other purposes. Natural gas is also used as the fuel for many manufacturing units of chemicals and fertilizers.

Question 6.
Why is it necessary to use coal and petroleum economically?
Answer:
There are two main reasons for which economical use of fossil fuels is necessary.
(i) Fossil fuels are exhaustible sources. If they are used indiscriminately, they will be exhausted, as they are present in nature in limited amount. It takes millions of years to form fossil fuels, so it is not possible to make new fossil fuels artificially.

(ii) Secondly, fossil fuels specially coke, petrol, diesel, etc. generate polluting gases on burning. Coke is almost carbon and produces carbondioxide on binning, whieh pollutes our environment. These polluting emissions have given rise to dangers of global warming and air pollution. So, their limited and economic use can control pollution and give better environment to live in.

Question 7.
Write some ways in which we can conserve fossil fuels.
Answer:
Economic and controlled consumption of fossil fuel can help conserving our natural resources. Following ways and measures can conserve owr resources:
(i) Vehicles shcaiM be driven at eeaastant and moderate speed.
(ii) Engines should he switched off at traffic lights or other temporary halts.
(iii) Proper and regular maintenance of vehicles.
(iv) Vehicle pooling can reduce number of vehicles plying on road thus less consumption of fuel.
(v) At home gas stoves should he cleaned properly and burners should not he left boring unnecessarily.
(vi) Pressure cookers should be preferred to pans. If pans are being used, they should he properly covered and their bottoms should not have deposits of burnt oil.
(vii) Small pans and burners should be used and pulses etc. should be dipped in water before cooking them.

Coal and Petroleum Class 8 HBSE Notes

1. We get various materials from various sources. These sources cam be natural or man-made. Natural resources are like air, water, soil, minerals, etc.
2. Natural resources are of two types according to their availability
(a) Inexhaustible
(b) Exhaustible.
3. Inexhaustible resources are those which are unlimited and are not supposed to come to an end by human use e.g. air is in exhaustible resource.
4. Exhaustible resourcs are those resources which are present in limited quantity and which can come to an end by human use e.g. forests, coal, petroleum, wildlife and natural gas, minerals, etc.
5. Coal, petroleum, natural gas etc. are called fossil fuels because they are formed by the decomposition of the dead bodies of plants and animals.
6. These fossil fuels are used by humans for their various energy requirements.
7. Coal was formed under the earth about 300 million years ago. The de forests of the earth got hurried under soil due to earthquakes and volcanic erruptions. The compressed under the layers of soil. Rising temperature under the earth converted these dead bodies into coal. Coal mainly consists of carbon.
8. The whole process of conversion of dead bodies of plants and animals into coal is called carbonization.
9. Heating of coal in absence oT cur to form coke is called destructive distillation. Destructive distillation is the process which produces various petroleum products like coaltar, coal-gas, etc.
10. Petroleum is refined to get various by-products like petrol, petroleum gas, paraffin wax, diesel, lubricating oil, etc.
11. All these resources of energy are present in limited quantity. It was a long process which took place to convert dead bodies of living beiqgs to get converted into petroleum products. So they will get exhausted if used indiscriminately.

Haryana State Board HBSE 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals Textbook Exercise Questions and Answers.

Haryana Board 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

HBSE 8th Class Science Materials: Metals and Non-Metals Textbook Questions and Answers

Question 1.
Which of the following can be beaten into thin sheets?
(a) Zinc
(b) Phosphorus
(c) Sulphur
(d) Oxygen
Answer:
(a) Zinc.

Question 2.
Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.
Answer:
(a) All metals are ductile. ✗
(b) All non-metals are ductile. ✗
(c) Generally, metals are ductile. ✓
(d) Some non-metals are ductile. ✗.

Question 3.
Fill in the blanks:
(a) Phosphorus is very ……….. non-metal.
(b) Metals are ……….. conductor of heat and ………….. .
(c) Iron is ………….. reactive than copper.
(d) Metals react with acids to produce ………….. gas.
Answer:
(a) reactive
(b) good, electricity
(c) less
(d) hydrogen.

Question 4.
Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) Generally, non-metals react with acids. ( )
(b) Sodium is a very reactive metal. ( )
(c) Copper displaces zinc from zinc sulphate solution. ( )
(d) Carbon can be drawn into wires. ( )
Answer:
(a) False
(b) True
(c) False
(d) False.

Question 5.
Some properties are listed in the following table. Distinguish between metals and non-metals on the basis of their properties.

Answer:

Question 6.
Give reasons for the following:
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.
Answer:
(a) Aluminium foils are used to wrap food items because aluminium can be beaten in sheets to form these thin wrapping sheets and it is soft and it does not react with food items.

(b) Immersion rods are made up of metallic substances because metals are good conductors of heat and electricity. They get hot very soon on passage of current and warm the water.

(c) Copper cannot displace zinc from its salt solution because copper is less reactive than zinc. A less reactive metal cannot displace a more reactive metal from its solution.

(d) Sodium and Potassium are stored in kerosene because they are very reactive and quickly react in air.

Question 7.
Can you store acidic lemon pickles in an aluminium utensils? Explain.
Answer:
No, we cannot store acidic lemon pickles in aluminium utensils because aluminium is a metal. Metals readily react with acids to produce hydrogen gas. So, when the aluminium metal comes in contact with acidic lemon pickles, it would react to release hydrogen, which would spoil the food and render it unfit to consume.

Question 8.
In the following table some substances are given in Column I. In Column II some uses are given. Match the items in Column I with those in Column II.

Answer:

Question 9.
What happens when:
(i) Dilute sulphuric acid is poured on a copper plate?
(ii) Iron nails are placed in copper sulphate solution?
Write word equations of the reactions involved.
Answer:
(i) When sulphuric acid is poured on copper plate the acid present in sulphuric acid reacts with copper to form copper sulphate and hydrogen. The copper plate gets eroded from place.
Sulphuric Acid + Copper → Copper Sulphate + Hydrogen
(ii) When iron nails are placed in copper sulphate solution the iron being more reactive will replace copper in its salt solution,
(Ferrous Sulphate) → Iron + Copper Sulphate → Iron Sulphate + Copper
The solution will turn light green.

Question 10.
Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.
(i) How will she find the nature of the gas?
(ii) Write down equations of all the reactions taking place in this process.
Answer:
(i) She will test it with litmus paper to check the acidic or basic nature of gas. If red litmus turns blue, it is basic in nature. If blue litmus turns red, it is acidic in nature.

(ii) Sulphur dioxide (SO₂) + Water (H₂O) → Sulphurous acid (H₂SO₃).

Question 11.
One day Reeta went to a Jeweller’s shop with her mother. Her mother gave old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back they found that there was a loss in its weight. Can you suggest a reason for the loss in weight?
Answer:
When gold is washed in acidic solution, it being a metal reacts with acid and forms the hydrogen gas with some metallic oxides. This causes the loss of gold in form of gold oxides. This looses the weight of gold.

Activity.

No. 4.1. Malleability Of Materials

No. 4.3. Electrical Conductivity Of Materials

Extended Learning – Activities And Projects

Question 1.
Prepare Index Cards for any four metals and non-metals. The card should have information like name of metal/non-metal; its physical properties, chemical properties and uses.
Answer:
1. Name of metal: Copper
Physical properties:
(i) It is hard
(ii) It is ductile.
(iii) It is good conductor of heat and electricity.

Chemical Properties:
(i) Copper reacts with moist air to form greenish coating.
(ii) It oxide is basic in nature.
(iii) It reacts with acids to produce hydrogen gas.
(iv) It displaces iron from iron sulphate solution.

Uses:
Copper is used to make electrical wires, base of cooking utensils, etc.

Non-metals:

2. Name of non-metal: Coal
Physical properties:
(i) It is not ductile.
(ii) It is not malleable.
(iii) It is hot sonorous and does not shine. It is soft.
(iv) It is poor conductor of electricity

Chemical Properties:
(i) It produces oxides of carbon when burnt
(ii) It’s oxide are acidic in nature.
(iii) It does not take part in replacement reaction.

3. Name of Non-metal: Sulphur
Physical properties:
(i) It is neithre ductile nor malleable.
(ii) It is soft and dull.
(iii) It is poor conductor of heat and electricity.

Chemical properties:
(i) It reacts with oxygen to produce sulphur dioxide.
(ii) It reacts with water to form sulphurous acid H₂SO₄ which is acidic in nature.
(iii) Metals are heated to mould them.
(iv) Gold is preferred to prepare jewellary because it is less reactive ductile and is a costly metal.

4. Name of Metal: Iron
Physical properites:
1. malleable
2. non-ductile
3. sonorous
4. hard
5. good conductor of heat and current.

Chemical properties:
1. React with oxygen to form rust.
2. React with water.
3. React with acids to form hydrogen gasi
4. React with sodium hydroxide to produce hydrogen gas.

Uses:
Used to make machines, tools, door, etc.

Question 2.
Visit a blacksmith and observe how metals are moulded.
Answer:
For self attempt.

Question 3.
Suggest an experiment to compare the conductivity of electricity by iron, copper, aluminium and zinc. Perform the experiment and prepare a short report on the results.
Answer:
For self attempt.

Question 4.
Find out the locations of the deposits of iron, aluminium and zinc in India. Mark these in an outline map of India. In which form are the deposits found? Discuss in the class.
Answer:
For self attempt.

Question 5.
Discuss with your parents / neighbours / goldsmiths why gold is preferred for making jewellery.
Answer:
For self attempt.

Question 6.
Visit the following websites and enjoy the quiz on metals and non-metals.

• chemistry.about.com /library/weekly/ bl05030a.htm
• chemistry.about.com / od / testsquizzes / Chemistry_Tests_Quizzes.htm.
• www.syvum.com / cgi / online / mult.cgi / squizzes / science / metals.tdf?0
• www.gcsescience.com / q / quesemet.html
• www.corrosionsource.com / handbook / periodic / metals.htm
  Answer:
  For self attempt.

HBSE 8th Class Science Materials: Metals and Non-Metals Important Questions and Answers

Very Short Answer Type Questions

Question 1.
What is meant by malleability of a metal?
Answer:
The property by virtue of which a metal can be hammered into thin sheets is called malleability.

Question 2.
What is meant by ductility of metals?
Answer:
Ductility of metals means that they can be drawn into very thin wires.

Question 3.
Name two metals which are both malleable and ductile.
Answer:
Gold and silver.

Question 4.
Are non-metals malleable and ductile?
Answer:
No.

Question 5.
Name a metal which exists in liquid state.
Answer:
Mercury.

Question 6.
Name the hardest substance in the world.
Answer:
Diamond.

Question 7.
Which metal is the best conductor of electricity?
Answer:
Silver.

Question 8.
Identify the most reactive and the least reactive metal amongst the following:
Al, K, Cu, Au.
Answer:
K is the most reactive while Au is the least reactive metal.

Question 9.
Name the metal which is stored in kerosene oil.

Answer:
Sodium is stored in kerosene oil.

Question 10.
Which metal foil is used in packing of some medicine tablets?
Answer:
Aluminium.

Question 11.
Which metal foil is used for decorating sweets?
Answer:
Silver.

Question 12.
Name a non-metal which is good conductor of heat.
Answer:
Graphite.

Question 13.
Why do gold and silver exist in free state?
Answer:
Gold and silver exist in free state because they are less reactive.

Question 14.
What would happen to the iron railings in open, when not painted?
Answer:
They will be rusted.

Question 15.
Why electric wires are made of copper?
Answer:
Electric wires are made of copper because it is good conductor of electricity.

Question 16.
Iron nails are kept dipped in blue copper sulphate solution and solution gets changed into light green colour. Why?
Answer:
This happens because iron displaces copper to form Ferrous Sulphate which is light green in colour.

Question 17.
Explain why silver does not displace hydrogen from dil HCl?
Answer:
Silver is less reactive than hydrogen, so it does not displace hydrogen from dil HCl.

Question 18.
When does red litmus paper turn blue?
Answer:
When red litmus paper comes in contact with basic solution.

Question 19.
When does a blue litmus paper turn red?
Answer:
Blue litmus paper turns red when it comes in contact with acidic solution.

Question 20.
What happens when sulphur dioxide gets dissolved in water?
Answer:
Sulphurous acid is formed:
SO₂ + H₂O → H₂SO₃

Question 21.
Oxides of non-metals are generally of which nature?
Answer:
Oxides of non-metals are generally of acidic nature.

Question 22.
What happens when sodium comes in contact with water?
Answer:
Sodium catches fire and heat is released.

Question 23.
How do non-metals react with water?
Answer:
Non-metals do not react with water.

Question 24.
How do non-metals generally react with acids?
Answer:
Non-metals generally do not react with acids.

Question 25.
Which gas is emitted when metals react with acids?
Answer:
Hydrogen gas.

Question 26.
Write any use of non-metal.
Answer:
Non-metals are used in crackers.

Question 27.
Write any use of metals.
Answer:
Metals are used to make all means of transportation.

Question 28.
What is a displacement reaction?
Answer:
Reaction in which a more reactive metal displaces the less reactive metal from its compound in aqueous solution is called displacement reaction.

Short Answer Type Questions

Question 1.
Write any three physical characteristics of metals.
Answer:
(i) Metals can be hammered to make sheets so they are malleable.
(ii) Metals can be drawned into very thin wires, that means metals are ductile.
(ii) Metals are good conductors of heat and electricity.

Question 2.
Write any three physical characteristics of non-metals.
Answer:
(i) Non-metals are non-ductile and non- malleable.
(ii) Non-metals are non-sonorous.
(iii) Non-metals are poor conductors of heat and electricity.

Question 3.
What do you mean by sonorous materials?
Answer:
Materials which make a sound when they are hit hard with some other material are called sonorous materials. All metals except the soft ones are sonorous, while all non-metals are non-sonorous.

Question 4.
How do metals and non-metals react with oxygen?
Answer:
Metals react with oxygen to form oxides generally. These oxides are alkaline.
\(\begin{array}{ccc}
2 \mathrm{Mg} & +\mathrm{O}_{2} \rightarrow & 2 \mathrm{MgO} \\
\text { Magnesium } & \text { Oxygen } & \text { Magnesium oxide }
\end{array}\)
Non-metals also react with oxygen to form oxides but these oxides are acidic in nature.
\(\begin{array}{cc}
\mathrm{C} & \mathrm{O}_{2} \\
\text { Carbon } & \text { Oxygen }
\end{array} \quad \rightarrow \quad \mathrm{CO}_{2}\)

Question 5.
A copper coin is kept immersed in a solution of silver nitrate for some time. What will happen to the coin and the colour of the solution?
Answer:
Copper is more reactive than silver. Therefore, when a copper coin is kept immersed in a solution of silver nitrate, it will displace silver from silver nitrate solution and a solution of copper nitrate will be formed.
Thus, the copper coin will dissolve in the solution and the colour of the solution will change from colourless to blue.

Question 6.
Explain why zinc metal can displace copper from copper sulphate solution but copper cannot displace zinc from zinc sulphate solution.
Answer:
Zinc metal is more reactive than copper. Therefore, it can displace copper from CuS0₄. Cu is less reactive than Zn, therefore, cannot replace Zn from ZnS0₄.

Zn + CuSO₄ → ZnSO₄ + Cu

Question 7.
State any three reasons for counting sulphur amongst the non-metals.
Answer:
Sulphur is a non-metal because:
(i) It is neither malleable nor ductile.
(ii) It does not conduct heat and electricity.
(iii) It combines with oxygen to form acidic oxide.

Question 8.
Non-metals do not react with water. How does this fact is utilized to store very reactive non-metals?
Answer:
Non-metals do not react with water. This quality is quite helpful in protecting some highly reactive non-metals which quickly react in air. Phosphorus is very reactive non-metal. It immediately catches fire when exposed to air. To prevent this, it is stored in water.

Question 9.
What is an element?
Answer:
Element is the smallest unit of any material. It cannot be broken further by cooling, heating or by electrolysis e.g. sulphur, iron, carbon etc.

Question 10.
Compare the physical properties of metals and non-metals.
Answer:

Question 11.
Compare the chemical properties of metals and non-metals.
Answer:

Question 12.
In which state do metals occur inside the earth’s crust?
Answer:
Metals occur in different states inside the earth’s crust depending upon their reactivity. Some metals occur in elemental state or in the form of compounds. Reactive metals generally are found in compound. Highly unreactive metals occur in free state while the less reactive metals can either be found in combined state or infree state.

Question 13.
What do you mean by Malleability of metals.
Answer:
The physical property of metals by virtue of which metals can be beatan into thin sheet is called malleability. Most of the metals are malleable. Aluminium is beaten into aluminium foil for wrapping food and silver is also beaten to make silver foils to decorate sweets.

Question 14.
What do you mean by ductility?
Answer:
The physical property by virtue of which metals can be drawn into thin wires is called ductility. Metals which are good conductors of electricity are mostly drawn into wire to be used in electrical cables. Gold and silver are the most ductile metal. Wires of copper, aluminium and tungsten are used to make electricity cables and tungsten is used to make filaments of bulbs. Aluminium wires are also widely used to make electrical wires.

Question 15.
What is an alloy? Describe any one alloy.
Answer:
Mixture of two or more than two metals to get desired qualities is called an alloy. Stainless steel is an alloy of iron, chromium and nickel. It is used to make utensils, surgical & instruments and many other decorative items. Stainless stell is hard and do not rust.

Long Answer Type Questions

Question 1.
Write a short note on displacement reaction of metals.
Answer:
A more reactive metal displaces a less reactive metal from its compound in an aqueous solution. This is called displacement reaction. For example, when some iron nails are dipped in copper sulphate solution, the iron being more reactive displaces copper from its solution and form ferrous sulphate solution of light green colour.

Similarly, magnesium and zinc also displaces copper from its compound.

Question 2.
How will you prove the nature of rust or the ash obtained from burning magnesium ribbon?
Answer:
This can be easily proved in laboratory. Take some rust and dissolve it in water (a few drops). Now take a red litmus paper and dip the litmus paper in solution. We will see that the red litmus paper turns blue.

When the red litmus paper turns blue it means solution is basic in nature. So the rust is basic in nature. We can similarly check the nature of ash obtained by burning a magnesium ribbon. It will also turn red litmus paper blue proving its basic nature.

Question 3.
How do different metals react with water?
Answer:
Different metals react differently with water, hydrogen being a common end product.
Sodium metal reacts vigorously with water to form sodium hydroxide and hydrogen gas.

Magnesium only reacts with hot boiling water to form magnesium oxide and hydrogen.

Red hot iron reacts with steam to form iron oxide and hydrogen copper. Silver and nickel do
not react with water.

Question 4.
What are the different uses of metals?
Answer:
Metals are very useful to us. Some of the uses of common metals are following:
(а) Copper and aluminium metals are used to make electric wires. This is because copper and aluminium are good conductors of electricity.
(b) Copper, aluminium and iron metals are used for making utensils and other domestic things. These metals are also used to make various factory equipments. This is because, all these metals are good conductors of heat.
(c) Iron is used to make heavy machinery and is also used in construction of buildings because it is very heavy and strong.
(d) Thin foils of aluminium are used in packaging food materials and medicines etc.
(e) The liquid metal mercury is used in thermometers.
(f) Gold and silver metals are used to make jewellery.
(g) Sodium, titanium and zirconium metals are used in atomic energy and space projects.

Question 5.
What are the different uses of non-metals?
Answer:
Following are the uses of non-metals:
(a) Oxygen is used by plants and animals for respiration. Oxygen also supports the process of combustion in factories, houses, aeroplanes
and missiles.
(b) Compounds of nitrogen provide nutrients to soil and plants. Fertilizers made by using nitrogen are extensively used in agricultural practices.
(c) Chlorine is used to disinfect the drinking water as it has the ability to kill germs.
(d) Sulphur is also used as germicide, it is also used as an antiseptic fcr skin treatment (in ointments).
(e) Non-metals are used in crackers.

Question 6.
What is corrosion? How does it affect different metals?
Answer:
Corrosion is defined as attack of atmospheric gases and moisture on the surfaces of metal making them deformed and weak. If iron is left in open for a period of time, it slowly gets deposits of brown flakes on it, which is called rusting of iron. It is undesirable because it makes the iron weak and eat it up slowly with passage of time. Similarly silver objects become black in colour and loose their lustree as silver reacts with hydrogen sulphide gas of air. Slowly the copper vessels also get coated with greenish layer of copper carborate. It is formed due to reaction of copper with carbondioxide of air and water vapour also present in air.

Question 7.
Write composition, properties and uses of following alloys: Steel, Stainless Steel, Brass and Duralumin
Answer:

Materials: Metals and Non-Metals Class 8 HBSE Notes

1. All metals and non-metals have some physical and chemical properties which differentiate them from each other.
2. Properties related to appearance and structure are called physical properties while how they react with other metals and non-metals are called their chemical properties.
3. Metals are shiny in appearance. This property of metals is called lustre.
4. Metals are generally hard. Sodium and potassium are soft. All metals mostly exist in solid state except murcury which is a liquid at room temperature.
5. Metals can be beaten with hamrqer and can be beaten into sheets. This physical property of metals is called malleability. Most of the metals are malleable.
6. Metals can be drawn into wires, they are thus ductile . Gold, tungsten are highly ductile metals.
7. Metals are good conductors of heat and electricity. That is why metals are used to make electric wires and most of the cooking utensils are made of metals. Silver is the best conductor of electricity.
8. Metals make sound, when they are hit hard with other object. This property makes them sonorous.
9. Non-metals do not shine and break-up when hit hard with hammer.
10. Non-metals cannot be beaten into sheets.
11. Non-metals cannot be drawn into wires.
12. They do not make any sound when hit with other objects.
13. Non-metals are bad conductors of heat and electricity.
14. Metals and non-metals react with oxygen to form oxides. Metal oxides are alkaline and oxides of non-metals are acidic in nature.
15. Metals react with water at different rates to form oxides and hydrogen gas. Non-metals do not react with water except sodium and magnesium.
16. Non-metals generally do not react with acids but metals react to produce hydrogen gas.
17. A more reactive metal displaces the less reactive metal from its compound in aqueous solution.
18. Metals and non-metals are very useful to us. They are used for different purposes.
19. All the materials can be divided into metals, non-metals and metalloids on the basis of above discussed physical mid chemical properties. Metalloids are those materials which possess the qualities of both metals and non-metals.