Textual Dictionary
Chapter Five
Energy and Matter
Elementary Science Class Five (English Version)
All words below are taken from this chapter, and their meanings are given in clear English.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| energy (EN-er-jee) | The ability to do work. | ability (skill) power (strength) | — | We use energy in every work. বাংলা অর্থ: We need energy for all kinds of work. |
| matter (MAT-er) | A thing that has weight and occupies space. | substance (material) | — | Even the air, which we cannot see, is also a matter. বাংলা অর্থ: Air is matter although we cannot see it. |
| source (sors) | A place or thing from which energy comes. | origin (starting point) provider (giver) | — | The main source of all energy is the Sun. বাংলা অর্থ: The Sun is the main origin of all energy. |
| transformation (trans-for-MAY-shun) | A change of energy from one form to another. | change (alteration) conversion (turning into another form) | — | Energy can be changed from one form to another. বাংলা অর্থ: One form of energy can become another form. |
| conduction (kon-DUK-shun) | The transmission of heat through solid matter. | transmission (passing) transfer (moving) | — | Transmission of heat through solid matter is called conduction. বাংলা অর্থ: Heat moving through a solid is conduction. |
| radiation (ray-dee-AY-shun) | The process in which energy is emitted without any medium. | emission (giving out) transmission (passing) | — | Radiation can work without any medium. বাংলা অর্থ: Radiation does not need a medium. |
| molecule (MOL-uh-kyool) | A very tiny particle that makes up matter. | particle (tiny part) unit (single part) | — | Any matter is made up of tiny particles called molecules. বাংলা অর্থ: Matter consists of very small molecules. |
| solid (SOL-id) | A state of matter in which molecules are very close together. | — | liquid (flowing state) gaseous (gas state) | In the solid state, the molecules of water are very close to each other. বাংলা অর্থ: In ice, water molecules stay very close together. |
| preserve (pri-ZURV) | To protect something and keep it safe. | save (keep safe) protect (keep from harm) | wasting (using carelessly) | By saving energy we can help to preserve energy resources. বাংলা অর্থ: Saving energy helps us protect energy resources. |
Dictionary entries: 9
1. How to Use This Sheet
Learner Guide
- Read the chapter before studying the word list.
- Cover the meaning column and test yourself on each word.
- Say each word aloud using the Bengali pronunciation guide.
- Read the example sentence to understand the word in context.
- Use the example sentences for writing practice.
- Review the key points after completing the vocabulary practice.
Textual Dictionary
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| energy (এনার্জি) | The ability to do work. | ability (skill), power (strength) | — | We use energy in every work. Energy helps us to walk to school. |
| matter (ম্যাটার) | A thing that has weight and occupies space. | substance (material) | — | Air is matter although we cannot see it. |
| source (সোর্স) | A place or thing from which energy comes. | origin (starting point), provider (giver) | — | The Sun is the main source of all energy. |
| transformation (ট্রান্সফরমেশন) | A change of energy from one form to another. | change (alteration), conversion (turning into another form) | — | Energy can be changed from one form to another. |
| conduction (কনডাকশন) | The transmission of heat through solid matter. | transmission (passing), transfer (moving) | — | Heat moving through a solid is conduction. |
| radiation (রেডিয়েশন) | The process in which energy is emitted without any medium. | emission (giving out), transmission (passing) | — | Radiation does not need a medium. |
| molecule (মলিকিউল) | A very tiny particle that makes up matter. | particle (tiny part), unit (single part) | — | Matter consists of very small molecules. |
| solid (সলিড) | A state of matter in which molecules are very close together. | — | liquid (flowing state), gaseous (gas state) | In ice, water molecules stay very close together. |
| preserve (প্রিজার্ভ) | To protect something and keep it safe. | save (keep safe), protect (keep from harm) | wasting (using carelessly) | Saving energy helps us preserve energy resources. |
Dictionary entries: 9
★ Key Points
- Energy is the ability to do any work.
- We use energy to walk, ride a bicycle, run a computer, cook food, and move a car.
- The Sun is the main source of all energy.
- Energy can change from one form to another through energy transformation.
- Heat transmission moves thermal energy from a warmer place to a cooler place.
- Conduction is the transmission of heat through solid matter.
- Convection transfers heat through liquids and gases.
- Radiation can transfer energy without any medium.
- Matter has weight and occupies space, and air is also matter.
- All matter is made up of tiny particles called molecules.
- Water can exist as ice, water, and water vapour.
- Saving energy helps preserve energy resources and prevent pollution.
2. Key Words - Main Table (1-15)
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| energy (EN-er-jee) | The ability to do work. | power; strength | — | We use energy in every work. We need energy to walk to school. |
| ability (uh-BIL-uh-tee) | The power or skill to do something. | skill; power | inability | Energy is the ability to do any work. |
| work (wurk) | An activity or task that is done. | activity; task | rest | We use energy in every work. |
| forms (formz) | Different types or kinds of something. | types; kinds | — | There are many different forms of energy. |
| source (sors) | A place or thing from which energy comes. | origin; provider | — | The Sun is the main source of all energy. |
| coal (kohl) | A source from which energy can come. | fuel; resource | — | Sometimes energy comes from coal. |
| oil (oyl) | A source of energy. | fuel; resource | — | Sometimes energy comes from oil or food. |
| food (food) | A source that provides energy to living things. | fuel; nourishment | — | We need energy to cook our food. |
| wind (wind) | Moving air that can provide energy. | air; breeze | stillness | Sometimes energy comes from wind. |
| water (WAW-ter) | A substance that can be a source of energy. | liquid; water current | — | Sometimes energy comes from water current. |
| battery (BAT-er-ee) | A source that provides energy. | power source; cell | — | Sometimes we get energy from a battery. |
| generator (JEN-er-ay-ter) | A source from which energy can be obtained. | power source; provider | — | Sometimes we get energy from a generator. |
| heat (heet) | A form of energy that makes things warm. | thermal energy; warmth | cold | We get heat and light from different sources. |
| light (lyte) | A form of energy that helps us to see. | brightness; illumination | darkness | Light is the form of energy that helps us to see. |
| electricity (ee-lek-TRIS-uh-tee) | A form of energy used by electrical devices. | electrical energy; power | — | We get electricity from different sources. |
★Key Points
- Energy is the ability to do any work.
- People use energy to walk, ride a bicycle, run a computer, cook food, and move a car.
- Energy comes from sources such as coal, oil, food, wind, water current, batteries, and generators.
- The Sun is the main source of all energy.
- Heat, light, electricity, and sound are forms of energy.
- Energy can change from one form to another, and this change is called energy transformation.
- Plants change light energy from the Sun into chemical energy when they make food.
- Solar panels can change light energy into electrical energy.
- Heat moves from a warmer place to a cooler place.
- Conduction transfers heat through solid matter, convection transfers heat through liquids and gases, and radiation transfers energy without a medium.
- Matter has weight and occupies space, and air is also matter.
- All matter is made up of tiny particles called molecules.
3. Key Words - Main Table (16-30)
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| sound (/saʊnd/) | A form of energy that can be heard. | noise; tone | silence; quiet | We get sound energy from different sources. We can receive sound energy from different sources. |
| solar (/ˈsoʊlər/) | Related to the Sun. | sun-powered; sunlight-based | — | Solar panels can change light energy into electrical energy. Panels using sunlight can change light energy into electrical energy. |
| chemical (/ˈkemɪkəl/) | Related to a substance and its energy. | substance-based; molecular | — | Plants change light energy into chemical energy when they make food. Plants change sunlight energy into stored food energy. |
| mechanical (/məˈkænɪkəl/) | Related to movement or the action of machines. | moving; machine-related | still; motionless | Animals transform stored chemical energy into heat and mechanical energy. Animals change stored food energy into heat and movement energy. |
| stored (/stɔːrd/) | Kept for later use. | saved; kept | used; released | Animals use stored chemical energy from plants. Animals use chemical energy kept in plants. |
| directly (/dəˈrektli/) | In a straight or immediate way. | immediately; straightaway | indirectly; slowly | We get solar energy directly as light and heat. We receive sunlight energy immediately as light and heat. |
| transfer (/trænsˈfɜːr/) | To move energy from one place to another. | move; transmit | keep; retain | Convection transfers heat through liquids and gases. Convection moves heat through liquids and gases. |
| thermal (/ˈθɜːrməl/) | Related to heat. | heat-related; warm | cold; cool | Thermal energy is transferred from a warmer place to a cooler place. Heat energy moves from a warmer place to a cooler place. |
| warmer (/ˈwɔːrmər/) | Having more heat than another place or thing. | hotter; heated | cooler; colder | Heat moves from a warmer place to a cooler place. Heat travels away from the hotter place. |
| cooler (/ˈkuːlər/) | Having less heat than another place or thing. | colder; less warm | warmer; hotter | Heat is transferred to a cooler place. Heat moves towards the place with less heat. |
| conduction (/kənˈdʌkʃən/) | The transmission of heat through solid matter. | heat transfer; transmission | — | The spoon is heated by hot water through conduction. Heat moves through the solid spoon by conduction. |
| convection (/kənˈvekʃən/) | The transmission of heat through liquids and gases. | heat circulation; movement | — | Convection transfers heat through liquids and gases. Heat moves through liquids and gases by convection. |
| emitted (/ɪˈmɪtɪd/) | Sent out from a source. | released; given out | received; absorbed | Radiation is the process in which energy is emitted from a source. Radiation sends energy out from its source. |
| medium (/ˈmiːdiəm/) | A material through which energy can travel. | material; substance | emptiness; space | Radiation can work without any medium. Radiation can travel without a material path. |
| preserve (/prɪˈzɜːrv/) | To protect and keep something safe. | protect; save | waste; destroy | By saving energy we can help to preserve energy resources. Saving energy helps protect energy resources. |
Dictionary entries: 15
★Key Points
- Sound is one form of energy obtained from different sources.
- Solar energy comes from the Sun as light and heat.
- Plants change light energy into chemical energy when they make food.
- Animals transform stored chemical energy into heat and mechanical energy.
- Energy can be transferred from one place to another.
- Thermal energy moves from a warmer place to a cooler place.
- Conduction transfers heat through solid matter.
- Convection transfers heat through liquids and gases.
- Radiation emits energy without any medium.
- Saving energy helps preserve energy resources and prevent pollution.
4. Subject Terms and Definitions
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| energy (EN-er-jee) | The ability to do any work. | ability; power | — | We use energy to ride a bicycle. Energy is used for riding a bicycle. |
| source (sors) | A place or thing from which energy comes. | origin; provider | — | The Sun is the main source of all energy. The Sun provides the main energy source. |
| transformation (trans-for-MAY-shun) | A change of energy from one form to another. | change; conversion | — | Energy transformation changes energy from one form to another. One form of energy becomes another form. |
| conduction (kon-DUK-shun) | The transmission of heat through solid matter. | transmission; transfer | — | Heat spreads through the metal spoon by conduction. Heat moves through the solid spoon by conduction. |
| convection (kon-VEK-shun) | The transmission of heat energy through liquids and gases. | transmission; movement | — | Convection transfers heat through liquids and gases. Heat moves through water by convection. |
| radiation (ray-dee-AY-shun) | The process in which energy is emitted from a source without any medium. | emission; transmission | — | We feel the heat of the Sun through radiation. Radiation transfers heat across space. |
| matter (MAT-er) | A thing that has weight and occupies space. | substance; material | — | Air is matter although we cannot see it. Air has weight and occupies space. |
| molecule (MOL-uh-kyool) | A very tiny particle that makes up matter. | particle; unit | — | Any matter is made up of tiny particles called molecules. Molecules make up all matter. |
| atom (AT-um) | A particle smaller than a molecule. | particle; unit | — | A water molecule contains hydrogen atoms and an oxygen atom. Atoms make up a water molecule. |
| solid (SOL-id) | A state of matter in which molecules are very close together. | — | liquid; gaseous | In ice, water molecules stay very close to each other. Ice is the solid state of water. |
Dictionary entries: 10
◆Key Points
- Energy is the ability to do any work.
- The Sun is the main source of all energy.
- Energy can change from one form to another through energy transformation.
- Plants change light energy from the Sun into chemical energy when they make food.
- Animals transform stored chemical energy into heat and mechanical energy.
- Conduction transfers heat through solid matter.
- Convection transfers heat through liquids and gases.
- Radiation can transfer energy without any medium.
- Matter has weight and occupies space, and air is also matter.
- All matter is made up of tiny particles called molecules.
- Water can exist as ice, water, and water vapour.
- Saving energy helps preserve energy resources and prevent pollution.
5. Words in Context
Energy comes from a source, and the Sun is the main source of all energy. Energy may change through transformation: plants change light energy into chemical energy, while solar panels change light energy into electrical energy.
Heat can move by conduction through a solid spoon, by convection through water, or by radiation from the Sun. These processes transfer energy in different ways.
Matter has weight and occupies space. Every kind of matter is made up of tiny particles called molecules. We should preserve energy resources by using energy wisely and avoiding waste.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| source (sors) | A place or thing from which energy comes. | origin; provider | — | The Sun is the main source of all energy. The Sun is the main source of all energy. |
| transformation (trans-for-MAY-shun) | A change of energy from one form to another. | change; conversion | — | Energy transformation changes energy from one form to another. Energy transformation changes energy from one form to another. |
| conduction (kon-DUK-shun) | The transmission of heat through solid matter. | transmission; transfer | — | Heat spreads through the metal spoon by conduction. Heat spreads through the metal spoon by conduction. |
| convection (kon-VEK-shun) | The transmission of heat energy through liquids and gases. | transmission; movement | — | Convection transfers heat through liquids and gases. Convection transfers heat through liquids and gases. |
| radiation (ray-dee-AY-shun) | The process in which energy is emitted without any medium. | emission; transmission | — | We feel the heat of the Sun through radiation. We feel the heat of the Sun through radiation. |
| matter (MAT-er) | A thing that has weight and occupies space. | substance; material | — | Air is matter although we cannot see it. Air is matter although we cannot see it. |
| molecule (MOL-uh-kyool) | A very tiny particle that makes up matter. | particle; unit | — | Any matter is made up of tiny particles called molecules. Any matter is made up of tiny particles called molecules. |
| preserve (pri-ZURV) | To protect something and keep it safe. | save; protect | waste | Saving energy helps us preserve energy resources. Saving energy helps us preserve energy resources. |
6. Exercise 1 - Match the Meaning
Match each word in Column A with the correct meaning in Column B. Write the correct letter beside each word.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| 1. energy (এনার্জি) | A. The process in which energy is emitted without any medium. | power; strength | — | We use energy in every work. |
| 2. matter (ম্যাটার) | B. A thing that has weight and occupies space. | substance; material | — | Air is matter although we cannot see it. |
| 3. source (সোর্স) | C. A state of matter in which molecules are very close together. | origin; provider | — | The Sun is the main source of all energy. |
| 4. transformation (ট্রান্সফরমেশন) | D. To protect something and keep it safe. | change; conversion | — | Energy can be changed from one form to another. |
| 5. conduction (কনডাকশন) | E. The transmission of heat through solid matter. | transmission; transfer | — | Heat spreads through the metal spoon by conduction. |
| 6. radiation (রেডিয়েশন) | F. A very tiny particle that makes up matter. | emission; transmission | — | Radiation can transfer energy without any medium. |
| 7. molecule (মলিকিউল) | G. The ability to do work. | particle; unit | — | Any matter is made up of tiny particles called molecules. |
| 8. solid (সলিড) | H. A place or thing from which energy comes. | — | liquid; gaseous | Ice is the solid state of water. |
| 9. preserve (প্রিজার্ভ) | I. A change of energy from one form to another. | save; protect | waste | Saving energy helps us preserve energy resources. |
| 10. convection (কনভেকশন) | J. The transmission of heat energy through liquids and gases. | transmission; movement | — | Convection transfers heat through liquids and gases. |
Answer Key: 1-G, 2-B, 3-H, 4-I, 5-E, 6-A, 7-F, 8-C, 9-D, 10-J
7. Exercise 2 - Fill in the Blanks
Instructions: Fill in each blank with the correct word from the word bank. Use each word only once.
Word Bank: energy, source, light, conduction, convection, radiation, molecules, solid, preserve, battery
- The ability to do work is called __________.
- The Sun is the main __________ of all energy.
- Plants use __________ energy from the Sun to make food.
- The transfer of heat through solid matter is called __________.
- Heat transfer through liquids and gases is called __________.
- Energy transfer without any medium is called __________.
- All matter is made up of tiny particles called __________.
- Ice is the __________ state of water.
- Saving energy helps us __________ energy resources.
- A __________ can provide energy for some devices.
Answer Key: 1. energy; 2. source; 3. light; 4. conduction; 5. convection; 6. radiation; 7. molecules; 8. solid; 9. preserve; 10. battery.
8. Exercise 3 - Synonyms and Antonyms
Read each word and write the correct synonym or antonym as directed.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| energy (EN-er-jee) | The ability to do work. | power; strength | — | Energy helps people ride bicycles. |
| matter (MAT-er) | A thing that has weight and occupies space. | substance; material | — | Air is matter although we cannot see it. |
| source (sors) | A place or thing from which energy comes. | origin; provider | — | The Sun is the main source of all energy. |
| transformation (trans-for-MAY-shun) | A change of energy from one form to another. | change; conversion | — | Energy transformation changes energy from one form to another. |
| conduction (kon-DUK-shun) | The transmission of heat through solid matter. | transmission; transfer | — | Heat spreads through a metal spoon by conduction. |
| radiation (ray-dee-AY-shun) | The process in which energy is emitted without any medium. | emission; transmission | — | Radiation can transfer energy without any medium. |
| solid (SOL-id) | A state of matter in which molecules are very close together. | — | liquid; gaseous | Ice is the solid state of water. |
| preserve (pri-ZURV) | To protect something and keep it safe. | save; protect | waste | Saving energy helps us preserve energy resources. |
| heat (heet) | A form of energy that makes things warm. | warmth; thermal energy | cold | We get heat and light from different sources. |
| light (lyte) | A form of energy that helps us to see. | brightness; illumination | darkness | Light travels as radiation. |
Worked Example Series
Ex. Write a synonym for energy.
Sol:
energy = power
power = a synonym of energy
Ans. power
energy = power
power = a synonym of energy
Ans. power
Ex. Write a synonym for preserve.
Sol:
preserve = protect
protect = a synonym of preserve
Ans. protect
preserve = protect
protect = a synonym of preserve
Ans. protect
Ex. Write an antonym for solid.
Sol:
solid ≠ liquid
liquid = an antonym of solid
Ans. liquid
solid ≠ liquid
liquid = an antonym of solid
Ans. liquid
Ex. Write an antonym for heat.
Sol:
heat ≠ cold
cold = an antonym of heat
Ans. cold
heat ≠ cold
cold = an antonym of heat
Ans. cold
Ex. Write a synonym for transformation.
Sol:
transformation = change
change = a synonym of transformation
Ans. change
transformation = change
change = a synonym of transformation
Ans. change
Answer Key
- energy — synonym: power
- matter — synonym: substance
- source — synonym: origin
- transformation — synonym: change
- conduction — synonym: transmission
- radiation — synonym: emission
- solid — antonym: liquid
- preserve — synonym: protect
- heat — antonym: cold
- light — antonym: darkness
9. Exercise 4 - Make Sentences
Read the words, understand their meanings, and write a meaningful sentence with each word.
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| forms (/fɔːrmz/) | Different types or kinds of something. | types; kinds | — | Heat and light are two forms of energy. Heat and light are two types of energy. |
| source (/sɔːrs/) | A place or thing from which energy comes. | origin; provider | — | The Sun is a natural source of energy. The Sun is a natural origin of energy. |
| battery (/ˈbætəri/) | A source that provides energy. | cell; power source | — | The battery provides energy for the device. The cell provides energy for the device. |
| generator (/ˈdʒenəreɪtər/) | A source from which energy can be obtained. | provider; power source | — | The generator supplies electricity during a power cut. The provider supplies electricity during a power cut. |
| radiation (/ˌreɪdiˈeɪʃən/) | The process in which energy is emitted without any medium. | emission; transmission | — | Radiation carries heat from the Sun through space. Emission carries heat from the Sun through space. |
| molecule (/ˈmɒlɪkjuːl/) | A very tiny particle that makes up matter. | particle; unit | — | A water molecule contains hydrogen and oxygen atoms. A water particle contains hydrogen and oxygen atoms. |
| preserve (/prɪˈzɜːrv/) | To protect something and keep it safe. | save; protect | waste; damage | Careful use of energy helps preserve resources. Careful use of energy helps protect resources. |
| convection (/kənˈvekʃən/) | The transmission of heat through liquids and gases. | heat transfer; circulation | — | Convection moves heat through water in a pot. Heat transfer moves through water in a pot. |
Answer Key: Use the model sentences above as examples. Write a new sentence with each word.
Ex. Make a sentence with forms.
Sol: forms = different types
Sentence = Heat and light are two forms of energy.
Ans. Heat and light are two forms of energy.
Sentence = Heat and light are two forms of energy.
Ans. Heat and light are two forms of energy.
Ex. Make a sentence with source.
Sol: source = a place or thing from which energy comes
Sentence = The Sun is a natural source of energy.
Ans. The Sun is a natural source of energy.
Sentence = The Sun is a natural source of energy.
Ans. The Sun is a natural source of energy.
Ex. Make a sentence with battery.
Sol: battery = a source that provides energy
Sentence = The battery provides energy for the device.
Ans. The battery provides energy for the device.
Sentence = The battery provides energy for the device.
Ans. The battery provides energy for the device.
Ex. Make a sentence with radiation.
Sol: radiation = energy emitted without any medium
Sentence = Radiation carries heat from the Sun through space.
Ans. Radiation carries heat from the Sun through space.
Sentence = Radiation carries heat from the Sun through space.
Ans. Radiation carries heat from the Sun through space.
Ex. Make a sentence with preserve.
Sol: preserve = protect and keep safe
Sentence = Careful use of energy helps preserve resources.
Ans. Careful use of energy helps preserve resources.
Sentence = Careful use of energy helps preserve resources.
Ans. Careful use of energy helps preserve resources.
10. Vocabulary MCQ (1-10)
Energy and Its Sources
1. What does energy mean in the chapter?
A. The ability to do workB. A kind of solidC. A place for waterD. A type of molecule
Sol: [A] Energy is the ability to do any work.
2. Which word means a place or thing from which energy comes?
A. SourceB. MatterC. RadiationD. Molecule
Sol: [A] A source is a place or thing from which energy comes.
3. Which word names a substance that can provide energy to living things?
A. FoodB. DarknessC. StillnessD. Space
Sol: [A] Food is a source that provides energy to living things.
Forms and Transformation of Energy
4. Which form of energy helps us to see?
A. Sound energyB. Light energyC. Chemical energyD. Mechanical energy
Sol: [B] Light is the form of energy that helps us to see.
5. What is an energy transformation?
A. A change from one form of energy to anotherB. The loss of all matterC. The movement of cold water onlyD. The making of a solid
Sol: [A] Energy transformation is the change of energy from one form to another.
6. When plants make food, light energy from the Sun changes into which energy?
A. Chemical energyB. Sound energyC. Heat onlyD. Electrical energy only
Sol: [A] Plants change light energy from the Sun into chemical energy.
Heat Transfer and Light
7. Heat moving through the solid material of a metal spoon is called what?
A. ConvectionB. RadiationC. ConductionD. Transformation
Sol: [C] Conduction is the transmission of heat through solid matter.
8. Which process can transfer energy without any medium?
A. ConductionB. ConvectionC. RadiationD. Freezing
Sol: [C] Radiation can work without a medium, so heat from the Sun can reach Earth through space.
Matter and Saving Energy
9. What is a molecule?
A. A very tiny particle that makes up matterB. A form of lightC. A source of heat onlyD. A type of energy transfer
Sol: [A] Any matter is made up of tiny particles called molecules.
10. Which action helps to preserve energy resources?
A. Leaving lights onB. Keeping the refrigerator door openC. Turning off appliances when not in useD. Using a car for every short journey
Sol: [C] Turning off unused appliances saves energy and helps preserve energy resources.
11. Quick Revision List
| Word (Pronunciation) | Meaning | Synonyms | Antonyms | Example Sentence |
|---|---|---|---|---|
| energy (ˈenərdʒi) | The ability to do work. | ability; power | — | We need energy to walk to school. |
| matter (ˈmætər) | A thing that has weight and occupies space. | substance; material | — | Air is matter although we cannot see it. |
| source (sɔːrs) | A place or thing from which energy comes. | origin; provider | — | The Sun is the main source of all energy. |
| transformation (ˌtrænsfərˈmeɪʃən) | A change of energy from one form to another. | change; conversion | — | Energy transformation occurs when light energy changes into electrical energy. |
| conduction (kənˈdʌkʃən) | The transmission of heat through solid matter. | transmission; transfer | — | Heat spreads along a metal spoon by conduction. |
| radiation (ˌreɪdiˈeɪʃən) | The process in which energy is emitted without any medium. | emission; transmission | — | Radiation carries heat from the Sun through space. |
| molecule (ˈmɒlɪkjuːl) | A very tiny particle that makes up matter. | particle; unit | — | Matter is made up of tiny particles called molecules. |
| solid (ˈsɒlɪd) | A state of matter in which molecules are very close together. | — | liquid; gaseous | In ice, water molecules stay very close to each other. |
| preserve (prɪˈzɜːrv) | To protect something and keep it safe. | save; protect | waste | Saving energy helps us preserve energy resources. |
★ Key Points
- Energy is the ability to do any work.
- The Sun is the main source of all energy.
- Energy can change from one form to another through energy transformation.
- Plants change light energy from the Sun into chemical energy when they make food.
- Heat moves from a warmer place to a cooler place.
- Conduction transfers heat through solid matter.
- Convection transfers heat through liquids and gases.
- Radiation can transfer energy without any medium.
- Matter has weight and occupies space.
- All matter is made up of tiny particles called molecules.
- Water can exist as ice, water, and water vapour.
- Saving energy helps preserve energy resources and prevent pollution.
12. Practice Bank
Creative Question 1
Read the situation and answer the questions: Rina walks to school in the morning. At home, her mother cooks food using a stove, and her father switches on a television in the evening. The Sun provides light and heat during the day.
a) What is energy? [2 marks]
b) Name two forms of energy mentioned in the situation. [4 marks]
c) Explain why the Sun is called the main source of all energy. [4 marks]
Creative Question 2
Read the situation and answer the questions: A plant receives light from the Sun and makes food. Later, a solar panel receives sunlight and supplies electricity. When a television is switched on, it produces light, heat, and sound.
a) What is meant by energy transformation? [2 marks]
b) State the energy change that takes place when a plant makes food. [4 marks]
c) Describe the energy changes that take place in a television after it is switched on. [4 marks]
Creative Question 3
Read the situation and answer the questions: A metal spoon is placed in hot water. After some time, its handle becomes hot. In another pot, heated water rises while cooler water moves downward. Heat from the Sun reaches Earth through space.
a) Name the process of heat transfer through a solid. [2 marks]
b) Explain how heat spreads through the metal spoon. [4 marks]
c) Distinguish between convection and radiation using the situation. [4 marks]
Creative Question 4
Read the situation and answer the questions: A piece of chalk is crushed into smaller pieces and then ground into powder. Water is found as ice, liquid water, and water vapour. The chalk and water are both forms of matter.
a) What is matter? [2 marks]
b) What are the tiny particles that make up matter called? [4 marks]
c) Describe how the molecules of water are arranged in ice, liquid water, and water vapour. [4 marks]