Questions with Answers

Water (Term 2 Chapter 2 | 4th Science)

Evaluation

I. Choose the correct answer.

1. Water is the most __________ resource on the Earth.

(a) precious

(b) solid

(c) gas

Answer: (a) precious 

2. Water exists in _________ states.

(a) two

(b) three

(c) four

Answer: (b) three 

3. At temperature below _______ water freezes to form ice.

(a) 10º C

(b) 100º C

(c) 0º C

Answer: (c) 0º C

4. ______ is the process by which water becomes water vapour.

(a) Condensation

(b) Evaporation

(c) Freezing

Answer: (b) Evaporation 

5. Which controls the ecological functions of life?

(a) Bicycle

(b) Water cycle

(c) Recycle water

Answer: (b) Water cycle

II. Fill in the blanks with suitable answer.

1. Water is converted into water vapour when it is heated (ice cube / water vapour).

2. Water becomes ice on freezing (heating / freezing).

3. Water droplets Combines to forms clouds (rain /clouds).

4. Water cycle increases the availability of ground water (water tank / ground water).

5. Roof top harvesting is a type of rainwater harvesting (Roof top harvesting / Watercycle).

III. Write True or False.

1. Water is a good example for all states of matter. (True)

2. Water cycle controls Earth‛s temperature. (True)

3. Water becoming water vapour on heating is called evaporation. (True)

4. 37% of our brain‛s mass consists of water. (False)

5. Roof top harvesting method is used in agriculture field. (False)

IV. Answer briefly.

1. Write the states of water.

The states of water are

• Solid

• Liquid

• Gas

2. What is freezing?

Freezing is the process when a liquid turns in to a solid.

3. Name the processes involved in water cycle.

• Evaporation

• Condensation

• Precipitation

4. Which state government made rain water harvesting as mandatory in the year 2001?

Tamil Nadu state government made rain water harvesting as mandatory in the year 2001.

5. What is needed to construct a rain water harvesting pit?

Gravels and coarse sand are needed to construct a rain water harvesting pit.

V. Answer in detail.

1. What is water cycle? Write any three importances of water cycle.

The continuous cycle through which water is circulated by different process like evaporation, condensation and precipitation is called water cycle.

Benefits of water cycle

• It improves the availability of ground water.

• It controls the Earth's Temperature.

• It recycles the Earth's supply of water constantly.

2. What is rain water harvesting? List out the advantages of rain water harvesting.

'Rainwater harvesting' is the process of collecting and storing rainwater for future use. Rainwater can be collected in natural reservoirs or artificial tanks.

Benefits of rainwater harvesting.

• It increases the ground water level.

• It can be used for agriculture.

• It increases the availability of water for living things.

VI. Colour the given picture and write the correct name in the given blanks.

 (Precipitation, Evaporation, Condensation, Water storage)

VII. Project.

 Make a model of house with roof top rain water harvesting system.

Let us do

See the given pictures and write down the state of each objects. (Solid, Liquid, Gas )

Let us do

Fill in the boxes given below with correct answers.

(Liquid, Solid, Melting, Freezing, Cooling, Heating, Gas)

Change of States in water

Try to Answer

1. Why water is a good example for all states of matter?

Answer: Because it is the only natural substance that can exist in all three states of matter at the temperatures normally found on Earth.

2. Which of the following is in liquid state? Rain/Ice/Snow

Answer: Rain

Let us do

• Fill water in an ice tray and keep it in the freezer. After few hours, take it out. What happened to the water?

The water changed from liquid state to solid state. It became ice.

• Now keep this ice tray on a table for some time. What happens to the ice?

Ice cubes melt and turn into water. Now water changes from solid state to liquid state.

• Pour water from the ice tray into a kettle. Ask an elder at your home to heat the kettle and observe the mouth of the kettle when the water starts boiling. What do you see?

We see white smoke (water vapour) coming out from the mouth of the kettle. Water changes from liquid state to gaseous state. It became steam.

Think and answer

What happens to the water in a wet cloth?

Answer: The water in a wet cloth gets evaporated. Hence the cloth gets dried up.

Try to Answer

Choose the correct answer.

In the water cycle ________

a. only evaporation is involved

b. only condensation is involved

c. evaporation and condensation are involved

Answer: (c) evaporation and condensation are involved

Try to Answer

1. Unscramble the words and fill in the blanks.

ondencsaonti, vaeionorpat, ecippitatrino

condensation, evaporation, precipitation

2. Is water cycle important for farming? Yes

3. Why is water cycle important to human? To improve the availability of ground water.

4. Name the process which is responsible for the formation of droplets on the surface of a glass of cold drink. condensation

Try to Answer

1. List out some other benefits of rain water harvesting.

Answer:

❖ Reduces flooding and Erosion.

❖ It increases ground water level

❖ It can be used for agriculture

❖ It increases the availability of water for living things

2. Suggest some ideas to save rainwater in your school.

Answer:

❖ By making rain water storage pits.

❖ By collecting rainwater from roof and allowing it to flow around borewells.

Let us do

Tips to construct a rainwater harvesting pit at school/home.

Construct a pit of any shape or size. It may be generally constructed, 1-2 metre wide and 2-3 metre depth. The pits can be filled with boulders, gravels and Coarse sand.

Put the boulders in the bottom, sand in the top and gravels in the middle.

Let us do

Discuss with your friends.

Rain water harvesting has an important role to protect our environment.

Answer: It increases the ground water level. It reduces flooding and soil erosion and reduces water scarcity.