Chapter 4
Air
Elementary Science Class Five (English Version)
Every word below is taken from this chapter; meanings are given in English.
Textual Dictionary
The following words are selected from Chapter 4 and explained according to their use in the chapter.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| important (im-PORT-uhnt) | having great value or need (significant) | vital (very necessary); major (very important) | — | Air is important for living things. Context: Air is very necessary for living things. |
| survive (sur-VYV) | to continue living (remain alive) | live (remain alive); continue (go on) | — | Without air, living things cannot survive. Context: Living things need air to remain alive. |
| breathe (breeth) | to take air into the body (draw in air) | — | — | Animals need oxygen from the air to breathe. Context: Animals take in oxygen from the air. |
| move (moov) | to change position or make something change position (go from one place to another) | travel (go from place to place); go (move from one place) | — | Wind can move wheels. Context: Moving air can make wheels turn. |
| produce (pruh-DOOS) | to make or create (make) | make (create); use (apply for a purpose) | — | Turbine blades are used to produce electricity. Context: Turbine blades help make electricity. |
| inflate (in-FLAYT) | to fill something with air (fill with air) | — | — | People use air to inflate footballs and tyres. Context: Air fills footballs and tyres. |
| harmful (HARM-ful) | causing harm or damage (bad for health or nature) | negative (bad); unwanted (not wanted) | — | Air pollution includes harmful gases. Context: Polluted air can harm living things. |
| prevent (pri-VENT) | to stop something from happening (keep from happening) | reduce (make less); clean (make free from pollution) | — | We should follow the 3 R's to prevent pollution. Context: The 3 R's help stop pollution. |
| clean (kleen) | free from unwanted dirt or pollution (not polluted) | — | polluted (made dirty); harmful (causing harm) | Planting trees is a good practice to keep air clean. Context: Trees help keep the air free from pollution. |
| reduce (ri-DOOS) | to make something less (lower the amount) | lessen (make less); prevent (stop from happening) | increase (make more) | Using less energy can reduce the consumption of fossil fuel. Context: Less energy use can make fossil-fuel use smaller. |
Count: 10 words
1. How to Use This Sheet
For the learner
- Read the chapter carefully before studying the dictionary.
- Cover the meaning column and test yourself on each word.
- Say each word aloud using its pronunciation guide.
- Read the example sentences to understand how the words are used.
- Use the example sentences as models for your own writing practice.
- Review the key points after completing the vocabulary work.
Textual Dictionary
These ten words are selected from Chapter 4 and explained according to their use in the chapter.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| important (im-PORT-uhnt) | having great value or need | significant; vital; major | — | Air is important for living things. |
| survive (sur-VYV) | to continue living | live; remain alive; continue | — | Without air, living things cannot survive. |
| breathe (breeth) | to take air into the body | — | — | Animals need oxygen from the air to breathe. |
| move (moov) | to change position or make something change position | travel; go | — | Wind can move wheels. |
| produce (pruh-DOOS) | to make or create | make; create | — | Turbine blades are used to produce electricity. |
| inflate (in-FLAYT) | to fill something with air | fill with air | — | People use air to inflate footballs and tyres. |
| harmful (HARM-ful) | causing harm or damage | negative; unwanted | — | Air pollution includes harmful gases. |
| prevent (pri-VENT) | to stop something from happening | reduce; stop | — | We should follow the 3 R's to prevent pollution. |
| clean (kleen) | free from unwanted dirt or pollution | — | polluted; harmful | Planting trees is a good practice to keep air clean. |
| reduce (ri-DOOS) | to make something less | lessen; prevent | increase | Using less energy can reduce the consumption of fossil fuel. |
Count: 10 words
★ Key Points
- Air is important for living things.
- Living things cannot survive without air.
- Plants use carbon dioxide from air to make food.
- Animals need oxygen from the air to breathe.
- Wind can move wheels and turbine blades.
- Wind can help people cool themselves and dry wet clothes.
- Air can be used to inflate footballs and tyres.
- Oxygen from a cylinder is given to patients with breathing problems, divers, and alpinists.
- Nitrogen is used to make urea and preserve some foods.
- Carbon dioxide is used in soft drinks and fire extinguishers.
- Air pollution includes unwanted chemicals, gases, dust particles, smoke, or odour.
- Reducing energy use, reusing, recycling, cleaning garbage, and planting trees can help prevent air pollution.
2. Key Words - Main Table (1-15)
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| important (im-PORT-uhnt) | Having great value or need | significant; vital; major | unimportant; minor | Air is important for living things. |
| survive (sur-VYV) | To continue living | live; remain alive; continue | die; perish | Without air, living things cannot survive. |
| breathe (breeth) | To take air into the body | inhale; draw in air | exhale; breathe out | Animals need oxygen from the air to breathe. |
| move (moov) | To change position or make something change position | travel; go; shift | stop; stay | Wind can move wheels. |
| produce (pruh-DOOS) | To make or create | make; create; generate | destroy; remove | Turbine blades are used to produce electricity. |
| cool (kool) | To make less hot | chill; refresh; lower the heat | heat; warm | People use a fan to cool themselves. |
| travel (TRAV-uhl) | To go from one place to another | go; journey; move | stay; remain | A sailboat uses wind to travel across the river. |
| dry (dry) | To remove water from something | dehydrate; drain; make dry | wet; moisten | Wind is used to dry wet clothes. |
| inflate (in-FLAYT) | To fill something with air | fill; pump up; expand | deflate; empty | People use air to inflate footballs and tyres. |
| oxygen (OK-si-jən) | A gas from the air needed for breathing | breathing gas; life-support gas | — | Patients with breathing problems are given oxygen from a cylinder. |
| nitrogen (NY-truh-jən) | A gas used to make urea and preserve some foods | — | — | Nitrogen is used to make urea. |
| preserve (pri-ZURV) | To keep something safe or fresh | protect; conserve; keep | spoil; waste | Nitrogen helps preserve some foods. |
| pollution (puh-LOO-shən) | The introduction of unwanted substances into the air | contamination; dirt; impurity | cleanliness; purity | Air pollution causes harm to living things. |
| harmful (HARM-ful) | Causing harm or damage | damaging; dangerous; negative | harmless; helpful | Air pollution includes harmful gases. |
| prevent (pri-VENT) | To stop something from happening | stop; avoid; protect against | allow; cause | We should follow the 3 R's to prevent pollution. |
◆ Key Points
- Air is important for all living things.
- Living things cannot survive without air.
- Plants use carbon dioxide from air to make food.
- Animals need oxygen from air to breathe.
- Wind can move wheels and turbine blades.
- Wind can help cool people and dry wet clothes.
- Air can be used to inflate footballs and tyres.
- Oxygen from a cylinder is given to people with breathing problems, divers, and alpinists.
- Nitrogen is used to make urea and preserve some foods.
- Carbon dioxide is used in soft drinks and fire extinguishers.
- Air pollution includes unwanted chemicals, gases, dust particles, smoke, and odour.
- Using less energy, reusing, recycling, cleaning garbage, and planting trees can help prevent air pollution.
3. Key Words - Main Table (16-30)
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| carbon dioxide (কার্বন ডাই-অক্সাইড) | A gas used by plants to make food and in soft drinks (a gas in air) | — | — | Plants use carbon dioxide from air to make food. |
| element (এলিমেন্ট) | A part or substance found in air (a component) | component; part | whole | People use the elements of air in different ways. |
| cylinder (সিলিন্ডার) | A container used to hold oxygen (a gas container) | container; tank | — | Patients are given oxygen from an oxygen cylinder. |
| diver (ডাইভার) | A person who goes under water (an underwater swimmer) | swimmer; underwater explorer | — | Divers are given oxygen from an oxygen cylinder. |
| alpinist (অ্যালপিনিস্ট) | A person who climbs high mountains (a mountain climber) | mountaineer; climber | — | Alpinists are given oxygen from oxygen cylinders. |
| fertiliser (ফার্টিলাইজার) | A substance used to help plants grow (plant nutrient) | plant food; manure | — | Nitrogen is used to make fertilisers called urea. |
| urea (ইউরিয়া) | A fertiliser made using nitrogen (a fertiliser) | fertiliser; plant food | — | Nitrogen is used to make urea. |
| fizz (ফিজ) | Bubbles in a soft drink (bubbling gas) | bubbles; sparkle | stillness | Carbon dioxide gives sodas a fizz. |
| soda (সোডা) | A soft drink containing bubbles (a fizzy drink) | soft drink; beverage | — | Carbon dioxide is used in soft drinks such as sodas. |
| extinguisher (এক্সটিংগুইশার) | A device used to put out fire (a fire-control device) | fire extinguisher; fire-control device | — | Carbon dioxide is used in fire extinguishers to put out fire. |
| unwanted (আনওয়ান্টেড) | Not wanted or needed (undesired) | undesired; unwelcome | wanted; welcome | Air pollution is the introduction of unwanted chemicals into the air. |
| substance (সাবস্ট্যান্স) | A particular kind of matter (a material) | material; matter | — | Air pollution introduces unwanted substances into the air. |
| odour (ওডার) | A smell, especially an unpleasant one (a smell) | smell; scent | — | Throwing garbage can cause air pollution by spreading odour. |
| fossil fuel (ফসিল ফুয়েল) | Fuel whose burning releases gases into the air (a fuel source) | fuel; energy source | — | Burning fossil fuels is a major cause of air pollution. |
| environment (এনভায়রনমেন্ট) | The natural world around living things (the natural surroundings) | surroundings; natural world | — | Air pollution can damage the natural environment. |
Count: 15 words
★ Key Points
- Plants use carbon dioxide from air to make food.
- Animals need oxygen from the air to breathe.
- Oxygen from a cylinder is given to patients with breathing problems, divers, and alpinists.
- Nitrogen is used to make the fertiliser called urea.
- Nitrogen helps preserve foods such as fish, meat, and chips in tins or packages.
- Carbon dioxide gives soft drinks such as sodas a fizz.
- Carbon dioxide is used in fire extinguishers to put out fire.
- Air pollution is the introduction of unwanted chemicals, gases, dust particles, smoke, or odour into the air.
- Burning fossil fuels is a major cause of air pollution.
- Air pollution can harm living things and damage the natural environment.
4. Subject Terms and Definitions
◆ Key Points
- Air is important for all living things.
- Living things cannot survive without air.
- Plants use carbon dioxide from air to make food.
- Animals need oxygen from the air to breathe.
- Wind can move wheels and turbine blades to produce electricity.
- Wind can cool people, dry wet clothes, and help a sailboat travel across a river.
- Air can be used to inflate footballs and the tyres of cars, bicycles, and rickshaws.
- Patients with breathing problems, divers, and alpinists are given oxygen from oxygen cylinders.
- Nitrogen is used to make urea fertilisers and to preserve foods such as fish, meat, and chips.
- Carbon dioxide gives soft drinks a fizz and is used in fire extinguishers to put out fire.
- Air pollution is the introduction of unwanted chemicals, gases, dust particles, smoke, or odour into the air.
- Using less energy, reusing, recycling, cleaning garbage, and planting trees can help prevent air pollution.
5. Words in Context
Air helps living things survive because animals need it to breathe. Moving air can move turbine blades and can also dry wet clothes. People use air to inflate the tyres of cars, bicycles, and rickshaws.
Different gases in air have different uses. Nitrogen can help preserve foods, while carbon dioxide is used in soft drinks and fire extinguishers. However, polluted air may contain harmful gases, smoke, dust particles, or unwanted odour.
People can prevent air pollution by using less energy, reusing and recycling materials, cleaning garbage, and planting trees. These actions help protect living things and the natural environment.
- survive — continue living
- preserve — keep something safe or fresh
- prevent — stop something from happening
6. Exercise 1 - Match the Meaning
Match each English word with its correct meaning. The meanings are shuffled.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| survive (সারভাইভ) | C. দুর্গন্ধ বা গন্ধ (an unpleasant smell) | remain alive (জীবিত থাকা); continue (চলতে থাকা) | die (মারা যাওয়া); perish (ধ্বংস হওয়া) | Without air, living things cannot survive. বায়ু ছাড়া জীবন্ত বস্তু বেঁচে থাকতে পারে না। |
| breathe (ব্রিদ) | H. বায়ু শরীরে নেওয়া (to take air into the body) | inhale (শ্বাস নেওয়া); draw in air (বায়ু টেনে নেওয়া) | exhale (শ্বাস ছাড়া); breathe out (বাইরে শ্বাস ছাড়া) | Animals need oxygen from the air to breathe. প্রাণীদের শ্বাস নেওয়ার জন্য বায়ু থেকে অক্সিজেন প্রয়োজন। |
| turbine (টারবাইন) | A. বিদ্যুৎ উৎপাদনে ব্যবহৃত ঘূর্ণায়মান বড় চাকা বা ব্লেড (a machine with blades turned by wind) | wheel (চাকা); generator (উৎপাদক যন্ত্র) | — | Wind is used to move the blades of a turbine to produce electricity. বিদ্যুৎ উৎপাদনের জন্য বাতাস টারবাইনের ব্লেড ঘোরাতে ব্যবহৃত হয়। |
| inflate (ইনফ্লেট) | J. বায়ু দিয়ে কোনো কিছু পূর্ণ করা (to fill something with air) | fill (ভরা); pump up (পাম্প করে ফুলানো) | deflate (বায়ু বের করে দেওয়া); empty (খালি করা) | People use air to inflate the tyres of cars, bicycles, and rickshaws. মানুষ গাড়ি, সাইকেল ও রিকশার টায়ার ফুলাতে বায়ু ব্যবহার করে। |
| preserve (প্রিজার্ভ) | E. নিরাপদ বা সতেজ রাখা (to keep something safe or fresh) | protect (রক্ষা করা); keep (রেখে দেওয়া) | spoil (নষ্ট হওয়া); waste (অপচয় করা) | Nitrogen is used to preserve foods such as fish, meat, and chips. মাছ, মাংস ও চিপসের মতো খাবার সংরক্ষণ করতে নাইট্রোজেন ব্যবহৃত হয়। |
| pollution (পলিউশন) | B. বায়ুতে অনাকাঙ্ক্ষিত পদার্থের প্রবেশ (the introduction of unwanted substances into the air) | contamination (দূষণ); impurity (অশুদ্ধতা) | cleanliness (পরিচ্ছন্নতা); purity (বিশুদ্ধতা) | Air pollution causes harm to living things. বায়ুদূষণ জীবন্ত বস্তুর ক্ষতি করে। |
| odour (ওডার) | I. কোনো গন্ধ, বিশেষ করে অপ্রীতিকর গন্ধ (a smell, especially an unpleasant one) | smell (গন্ধ); scent (সুবাস বা গন্ধ) | — | Throwing garbage can cause air pollution by spreading odour. আবর্জনা ফেললে গন্ধ ছড়িয়ে বায়ুদূষণ হতে পারে। |
| prevent (প্রিভেন্ট) | G. কোনো কিছু ঘটতে বাধা দেওয়া (to stop something from happening) | stop (থামানো); avoid (এড়ানো); protect against (রক্ষা করা) | allow (অনুমতি দেওয়া); cause (ঘটানো) | We should follow the 3 R's to prevent pollution. দূষণ প্রতিরোধ করতে আমাদের ৩টি R মেনে চলা উচিত। |
| reduce (রিডিউস) | D. কোনো কিছুর পরিমাণ কমানো (to make something less) | lessen (কমানো); lower (নিচে নামানো) | increase (বাড়ানো); raise (বৃদ্ধি করা) | Using less energy can reduce the consumption of fossil fuel. কম শক্তি ব্যবহার করলে জীবাশ্ম জ্বালানির ব্যবহার কমানো যায়। |
| environment (এনভায়রনমেন্ট) | F. জীবন্ত বস্তুর চারপাশের প্রাকৃতিক জগৎ (the natural world around living things) | surroundings (চারপাশের পরিবেশ); natural world (প্রাকৃতিক জগৎ) | — | Air pollution can damage the natural environment. বায়ুদূষণ প্রাকৃতিক পরিবেশের ক্ষতি করতে পারে। |
Answer Key
survive—C; breathe—H; turbine—A; inflate—J; preserve—E; pollution—B; odour—I; prevent—G; reduce—D; environment—F.
survive—C; breathe—H; turbine—A; inflate—J; preserve—E; pollution—B; odour—I; prevent—G; reduce—D; environment—F.
Count: 10 words
7. Exercise 2 - Fill in the Blanks
Word Bank: survive | oxygen | carbon dioxide | turbine | cool | travel | dry | inflate | nitrogen | pollution
Fill in each blank with the correct word from the word bank.
- Without air, living things cannot .
- Animals need from the air to breathe.
- Plants use from the air to make food.
- Wind turns the blades of a to produce electricity.
- People use a fan to themselves.
- A sailboat uses wind to across the river.
- Wind can help wet clothes.
- People use air to the tyres of bicycles.
- is used to preserve foods such as fish and meat.
- Air causes harm to living things.
Worked Examples
Ex. Without air, living things cannot ______.
Sol: The sentence describes continuing to live.
Blank = survive
Ans. survive
Blank = survive
Ans. survive
Ex. Animals need ______ from the air to breathe.
Sol: The sentence names the gas needed for breathing.
Blank = oxygen
Ans. oxygen
Blank = oxygen
Ans. oxygen
Ex. Plants use ______ from the air to make food.
Sol: The sentence names the gas used by plants to make food.
Blank = carbon dioxide
Ans. carbon dioxide
Blank = carbon dioxide
Ans. carbon dioxide
Ex. Wind can help ______ wet clothes.
Sol: The sentence describes removing water from clothes.
Blank = dry
Ans. dry
Blank = dry
Ans. dry
Answer Key: 1. survive 2. oxygen 3. carbon dioxide 4. turbine 5. cool 6. travel 7. dry 8. inflate 9. nitrogen 10. pollution
8. Exercise 3 - Synonyms and Antonyms
Study the table and use the words from the chapter to complete the exercise.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| important (im-PORT-uhnt) | Having great value or need | vital; major | unimportant; minor | Air is important for living things. |
| survive (sur-VYV) | To continue living | live; remain alive; continue | die; perish | Without air, living things cannot survive. |
| breathe (breeth) | To take air into the body | inhale; draw in air | exhale; breathe out | Animals need oxygen from the air to breathe. |
| move (moov) | To change position or make something change position | travel; go; shift | stop; stay | Wind can move wheels. |
| produce (pruh-DOOS) | To make or create | make; create; generate | destroy; remove | Wind is used to move turbine blades to produce electricity. |
| cool (kool) | To make less hot | chill; refresh; lower the heat | heat; warm | People use wind from a fan to cool themselves. |
| dry (dry) | To remove water from something | dehydrate; drain; make dry | wet; moisten | Wind is used to dry wet clothes. |
| inflate (in-FLAYT) | To fill something with air | fill; pump up; expand | deflate; empty | People use air to inflate footballs and tyres. |
| harmful (HARM-ful) | Causing harm or damage | damaging; dangerous; negative | harmless; helpful | Air pollution includes harmful gases. |
| prevent (pri-VENT) | To stop something from happening | stop; avoid; protect against | allow; cause | We should follow the 3 R's to prevent pollution. |
Exercise
Write a synonym or an antonym as directed.
- Write a synonym of important: __________
- Write an antonym of survive: __________
- Write a synonym of breathe: __________
- Write an antonym of move: __________
- Write a synonym of produce: __________
- Write an antonym of cool: __________
- Write a synonym of dry: __________
- Write an antonym of inflate: __________
- Write a synonym of harmful: __________
- Write an antonym of prevent: __________
Worked Examples
Ex. Give a synonym of important.
Sol:
Word = important
Synonym = vital
Ans. vital
Ex. Give an antonym of survive.
Sol:
Word = survive
Antonym = die
Ans. die
Ex. Give a synonym of move.
Sol:
Word = move
Synonym = travel
Ans. travel
Ex. Give an antonym of inflate.
Sol:
Word = inflate
Antonym = deflate
Ans. deflate
Ex. Give a synonym of prevent.
Sol:
Word = prevent
Synonym = stop
Ans. stop
Answer Key: 1. vital 2. die 3. inhale 4. stay 5. make 6. warm 7. dehydrate 8. deflate 9. damaging 10. allow
9. Exercise 4 - Make Sentences
Instruction: Study the words and write meaningful sentences about air and its uses.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| preserve (prih-ZURV) | To keep something safe or fresh | protect; conserve; keep | spoil; waste | Nitrogen helps preserve some foods. |
| cylinder (SIL-in-der) | A container used to hold oxygen | container; tank | — | Patients are given oxygen from an oxygen cylinder. |
| urea (yoo-REE-uh) | A fertiliser made using nitrogen | fertiliser; plant food | — | People use nitrogen to make urea. |
| odour (OH-der) | A smell, especially an unpleasant one | smell; scent | fragrance; freshness | Throwing garbage can spread odour. |
| recycle (ree-SY-kul) | To process used materials for use again | reuse; recover; reprocess | discard; waste; throw away | We can recycle materials to help prevent pollution. |
| sailboat (SAYL-boht) | A boat that uses wind to travel | boat; sailing vessel | — | A sailboat uses wind to travel across the river. |
| pinwheel (PIN-weel) | A small wheel that turns in the wind | wind wheel; toy wheel | — | The pinwheel turns when it is held against the wind. |
| garbage (GAR-bij) | Waste material that people throw away | waste; rubbish; litter | treasure; cleanliness | Cleaning garbage helps keep the air clean. |
Count: 8 words
Ex. Make a sentence with preserve.
Sol: Word = preserve
Sentence = Nitrogen helps preserve some foods.
Ans. Nitrogen helps preserve some foods.
Sentence = Nitrogen helps preserve some foods.
Ans. Nitrogen helps preserve some foods.
Ex. Make a sentence with cylinder.
Sol: Word = cylinder
Sentence = Patients are given oxygen from an oxygen cylinder.
Ans. Patients are given oxygen from an oxygen cylinder.
Sentence = Patients are given oxygen from an oxygen cylinder.
Ans. Patients are given oxygen from an oxygen cylinder.
Ex. Make a sentence with urea.
Sol: Word = urea
Sentence = People use nitrogen to make urea.
Ans. People use nitrogen to make urea.
Sentence = People use nitrogen to make urea.
Ans. People use nitrogen to make urea.
Ex. Make a sentence with recycle.
Sol: Word = recycle
Sentence = We can recycle materials to help prevent pollution.
Ans. We can recycle materials to help prevent pollution.
Sentence = We can recycle materials to help prevent pollution.
Ans. We can recycle materials to help prevent pollution.
Ex. Make a sentence with sailboat.
Sol: Word = sailboat
Sentence = A sailboat uses wind to travel across the river.
Ans. A sailboat uses wind to travel across the river.
Sentence = A sailboat uses wind to travel across the river.
Ans. A sailboat uses wind to travel across the river.
10. Vocabulary MCQ (1-10)
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| important (im-PORT-uhnt) | Having great value or need | significant; vital; major | unimportant; minor | Air is important for living things. |
| survive (sur-VYV) | To continue living | live; remain alive; continue | die; perish | Without air, living things cannot survive. |
| breathe (breeth) | To take air into the body | inhale; draw in air | exhale; breathe out | Animals need oxygen from the air to breathe. |
| move (moov) | To change position or make something change position | travel; go; shift | stop; stay | Wind can move wheels. |
| produce (pruh-DOOS) | To make or create | make; create; generate | destroy; remove | Wind is used to produce electricity. |
| inflate (in-FLAYT) | To fill something with air | fill; pump up; expand | deflate; empty | People use air to inflate footballs. |
| harmful (HARM-ful) | Causing harm or damage | damaging; dangerous; negative | harmless; helpful | Air pollution includes harmful gases. |
| prevent (pri-VENT) | To stop something from happening | stop; avoid; protect against | allow; cause | We should follow the 3 R's to prevent pollution. |
| clean (kleen) | Free from unwanted dirt or pollution | pure; unpolluted | polluted; harmful | Planting trees helps keep air clean. |
| reduce (ri-DOOS) | To make something less | lessen; lower; decrease | increase; raise | Using less energy can reduce fossil-fuel consumption. |
Practice Questions
Meanings
1. What does survive mean?
A. To continue livingB. To make foodC. To fill with airD. To remove water
Sol: [A] Survive means to continue living.
2. Which word means “to take air into the body”?
A. MoveB. BreatheC. ProduceD. Reduce
Sol: [B] Breathe means to take air into the body.
3. If a person fills a tyre with air, what does the person do?
A. Inflates itB. Dries itC. Preserves itD. Pollutes it
Sol: [A] Inflate means to fill something with air.
Synonyms and Antonyms
4. Which is a synonym of important?
A. MinorB. VitalC. HarmfulD. Polluted
Sol: [B] Vital means very necessary, like important.
5. Which is an antonym of harmful?
A. DangerousB. DamagingC. HarmlessD. Negative
Sol: [C] Harmless is the opposite of harmful.
6. Which word is an antonym of reduce?
A. LessenB. LowerC. DecreaseD. Increase
Sol: [D] Increase means to make more, opposite to reduce.
Usage in Context
7. Wind can move wheels and turbine blades to ______ electricity.
A. produceB. preventC. breatheD. preserve
Sol: [A] Turbine blades are used to produce electricity.
8. Planting trees helps keep the air ______.
A. harmfulB. cleanC. wetD. minor
Sol: [B] Trees help keep the air free from pollution.
9. Using less energy can ______ the consumption of fossil fuel.
A. increaseB. reduceC. inflateD. move
Sol: [B] Reduce means to make something less.
10. We should follow the 3 R's to ______ pollution.
A. preventB. produceC. inflateD. survive
Sol: [A] Prevent means to stop something from happening.
11. Quick Revision List
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| important (im-PORT-uhnt) | Having great value or need | significant; vital | unimportant; minor | Air is important for living things. |
| survive (sur-VYV) | To continue living | live; remain alive | die; perish | Without air, living things cannot survive. |
| breathe (breeth) | To take air into the body | inhale; draw in air | exhale; breathe out | Animals need oxygen from the air to breathe. |
| move (moov) | To change position or make something change position | travel; go | stop; stay | Wind can move wheels. |
| produce (pruh-DOOS) | To make or create | make; create | destroy; remove | Wind is used to produce electricity. |
| inflate (in-FLAYT) | To fill something with air | fill; pump up | deflate; empty | People use air to inflate footballs. |
| oxygen (OK-si-juhn) | A gas from the air needed for breathing | breathing gas; life-support gas | — | Patients with breathing problems are given oxygen from a cylinder. |
| nitrogen (NY-truh-juhn) | A gas used to make urea and preserve some foods | — | — | Nitrogen is used to make urea. |
| pollution (puh-LOO-shuhn) | The introduction of unwanted substances into the air | contamination; impurity | cleanliness; purity | Air pollution causes harm to living things. |
| prevent (pri-VENT) | To stop something from happening | stop; avoid | allow; cause | We should follow the 3 R's to prevent pollution. |
★ Key Points
- Air is important for all living things.
- Living things cannot survive without air.
- Plants use carbon dioxide from air to make food.
- Animals need oxygen from air to breathe.
- Wind can move wheels and turbine blades.
- Wind can help people cool themselves and dry wet clothes.
- Air can be used to inflate footballs and tyres.
- Oxygen from a cylinder is given to people with breathing problems, divers, and alpinists.
- Nitrogen is used to make urea and preserve some foods.
- Carbon dioxide is used in soft drinks and fire extinguishers.
- Air pollution includes unwanted chemicals, gases, dust particles, smoke, and odour.
- Using less energy, reusing, recycling, cleaning garbage, and planting trees can help prevent air pollution.
Count: 10 revision words.
12. Practice Bank
1. Read the stimulus and answer the questions.
Stimulus: Rina held a pinwheel against the wind. The wheel turned. She also saw a sailboat moving across the river and wet clothes drying outside.
ক. What happened to the pinwheel? [2 marks]
খ. Write two daily uses of wind from the stimulus. [4 marks]
গ. Explain how wind helps to dry wet clothes. [4 marks]
2. Read the stimulus and answer the questions.
Stimulus: A farmer uses nitrogen to make urea. A patient with breathing problems receives oxygen from a cylinder. Plants take carbon dioxide from the air to make food.
ক. Which gas do plants use to make food? [2 marks]
খ. Mention two uses of nitrogen described in the chapter. [4 marks]
গ. Explain why oxygen from a cylinder is given to some people. [4 marks]
3. Read the stimulus and answer the questions.
Stimulus: Smoke from factories and cars enters the air. People also burn wood and fossil fuels. The polluted air may harm human health and damage the natural environment.
ক. Name one source of air pollution from the stimulus. [2 marks]
খ. Write two harmful effects of air pollution on human health. [4 marks]
গ. Describe two ways to prevent air pollution. [4 marks]
4. Read the stimulus and answer the questions.
Stimulus: It is raining outside, but Mina wants to dry her wet clothes quickly. She places the clothes in an open place inside the house and uses moving air to help remove the water.
ক. What does wind remove from wet clothes? [2 marks]
খ. State two examples of using air in daily life. [4 marks]
গ. Explain how Mina can dry wet hair according to the chapter. [4 marks]
5. Read the stimulus and answer the questions.
Stimulus: A soft drink contains carbon dioxide to give it a fizz. A fire extinguisher uses carbon dioxide to put out fire. Air is also used to inflate footballs, car tyres and bicycle tyres.
ক. Which gas gives a soft drink a fizz? [2 marks]
খ. Name two things that can be inflated with air. [4 marks]
গ. Describe the two uses of carbon dioxide given in the stimulus. [4 marks]
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