Class 4 Science Lesson 6

Exercise

1. Fill in the blanks with an appropriate word.

a. The substances which have mass and volume are called
👉 matter

b. The matter in which molecules are very close to each other is called
👉 solid

c. The matter in which molecules are very far from each other is called
👉 gas

d. The matter in which molecules are packed loosely than the solid but stronger than the gas is called
👉 liquid

e. All three forms of the matter is seen naturally in
👉 water

2. Write true for the correct and false for the incorrect statement.

a. The liquid form of water is present in lakes, ponds, rivers and oceans.
👉 True

b. Vapour is the solid form of water.
👉 False

c. Snow, ice and hailstones are solid forms of water.
👉 True

d. Water cannot change the state of the matter.
👉 False

e. Water is colourless, odourless and tasteless.
👉 True

3. Choose the best answer from the given alternatives.

a. What is the process in which liquid changes into vapour?
👉 Evaporation

b. What is the process in which solid changes into liquid?
👉 Melting

c. What is the process in which vapour changes into liquid?
👉 Condensation

d. What is the process in which liquid changes into solid?
👉 Freezing

e. What is the process in which surface water travels to the sky and rains down on the earth?
👉 Water cycle

4. Match the following.

Ice → Frozen Water

Solidification → liquid change into solid

Evaporation → liquid change into vapour

Vapour → gaseous form of water

Water → no fixed shape

5. Answer the following questions in a word each.

a) What is process called in which rainwater is collected in a water tank?
👉 Rainwater harvesting

b) What percentage of total amount of water is drinkable on earth?
👉 3%

c) What is electricity produced from a rotating turbine with a river called?
👉 Hydroelectricity

d) What when mixed in river pollutes water?
👉 Garbage

e) What is the source of energy for the water cycle?
👉 Sun

6. Write any two differences between:

a) Melting and solidification

👉 Melting is the process in which solid changes into liquid on heating, whereas solidification is the process in which liquid changes into solid on cooling.

b) Surface water and underground water

👉 Surface water is found on the earth’s surface like rivers and ponds, whereas underground water is found below the earth and is collected from wells and springs.

7. Give reason.

a) Water is called a matter.

👉 Water is called a matter because it has mass and occupies volume.

b) Rainfall is important.

👉 Rainfall is important because it gives water to plants, animals, and helps in the water cycle.

c) We should protect water resources.

👉 We should protect water resources because water is limited and very important for life and the environment.

8. Study the given diagram and answer the following questions.

i) Which natural process is shown in the diagram?

👉 The water cycle is shown in the diagram.

ii) What is the role of the sun in this process?

👉 The sun provides heat energy to evaporate water into vapour.

iii) What is the advantage of this process?

👉 It brings rainfall and maintains the supply of water on the earth.

9. Answer the following questions.

a) Write any three uses of water in our daily life.

👉 We use water for drinking, cooking food, and washing clothes.

b) List at least three properties of water.

👉 Water is colourless, odourless, and tasteless.

c) What is a source of water? Give an example of an underground source of water.

👉 A source of water is a place where water is found. An example of underground source of water is a well.

d) What can be done to reduce the use of water?

👉 We can reduce water use by closing taps, washing many clothes at once, and using wet cloths for cleaning.

e) What activities can protect water resources?

👉 We can plant trees, avoid throwing waste in water sources, and keep the environment clean.

f) What is the importance of rainwater harvesting technology?

👉 Rainwater harvesting helps us to save rainwater for use in gardens, washing, and cleaning.

g) Describe the water cycle in brief.

👉 In the water cycle, water evaporates due to the sun’s heat, forms clouds after condensation, and falls again as rain, completing the cycle.

AIR

1. Fill in the blanks with the given words:

a) Air is a mixture of different 👉 gases.

b) The sheet of air covering the earth is called 👉 atmosphere.

c) The air is 👉 weightless.

d) To burn anything, 👉 oxygen is required.

e) Planting trees helps to reduce 👉 air pollution.

2. Choose the correct answer:

a) Which of the following is required for a living thing to breathe?
👉 ii. air

b) Which one of the following is the reason for the stench coming from the place which has been accumulating garbage for many days?
👉 ii. the odor comes from the garbage

c) Which of the following changes occurs when air is filled in a football?
👉 i. the weight of the football increases

d) Which one of the following activities helps control air pollution?
👉 ii. tree plantation

e) Which of the following is responsible for global warming?
👉 i. air pollution

3. Answer the following questions:

a) Write the uses of air in daily life.

👉 Air is used for breathing, burning, flying kites and balloons, running windmills, and moving seeds from one place to another. It is also used to fill tires, balls, and swimming tubes.

b) Even though there is air around us, we cannot see it, why?

👉 We cannot see air because it has no color, taste, or smell.

c) What is air pollution?

👉 The unwanted change in the quality of air due to the mixing of dust, smoke and harmful substances is called air pollution.

d) What human activities cause air pollution?

👉 Burning firewood, running vehicles, throwing garbage, and factory smoke cause air pollution.

e) What effect does air pollution have on the earth’s atmosphere?

👉 Air pollution harms the atmosphere and causes global warming.

f) What effect does air pollution have on people?

👉 Air pollution causes diseases like eye, lung, and heart problems.

g) Anu constructed a wind vane and tried to run it on a day when there was no wind. But it did not move. What must be the reason for this?

👉 The wind vane did not move because there was no wind to push it.

h) If there is air pollution in the area you live in, how will it affect public life? And what efforts can be made to reduce pollution?

👉 Air pollution makes people sick and causes accidents due to low visibility. To reduce it, we should plant trees, avoid burning things, and use clean energy like solar and electricity.

ROCKS

1. Fill in the blanks with words from the list:

a) Mountain is composed of snow and rock.

b) A rock is composed of one or more minerals.

c) Precious rocks are used to make jewelry.

d) The rock becomes turbulent to form soil.

e) Various metals are also found in rocks.

2. Choose the correct answer:

a) Why are rocks considered important for studying the history of the earth?
👉 ii. The rock bears the imprint of an animal.

b) Which of the following is a soft rock?
👉 i. chalk

c) Which of the following processes in a rock causes soil to form?
👉 iii. It expands and contracts continuously.

d) What is a rock made of?
👉 ii. a mixture of two or more minerals

e) The physical properties of rocks are different but all have one common property. What is that property?
👉 i. Minerals are found in all rocks.

3. Answer the following questions:

a) What is a rock?

👉 A rock is a hard solid material found on the land, river banks, mountains and underground. It is made of more than one mineral.

b) Distinguish between a soft and hard rock.

👉 Soft rocks can be cut with a knife or nail, but hard rocks need a hammer to break. Plants grow on soft rocks easily, but landslides happen more. Hard rocks don’t allow easy plant growth but landslides are less.

c) Write any two uses of rock.

👉 Rocks are used to build houses and make statues.

d) Name any two hard and soft rocks found around your school or home.

👉 Hard rocks: marble, granite
Soft rocks: chalk, limestone

f) Prepare a list of items made using rock in your school and home.

👉 Floors, walls, rooftops, steps, statues, grinders, and decorations are made using rocks.

g) Write down any four physical properties of rock.

👉 Rocks can be shiny or dull, rough or smooth, hard or soft, and have different shapes and colors.