Page 80 - ACTIVE SCIENCE 4 TOC

1. Turn off the taps properly.

2. Do not leave the tap open while brushing, washing clothes and washing dishes.

3. Do not wash your cars with pipes, instead use a bucket.

4. Applying rainwater harvesting technique in our homes. It is the collection

and storage of rainwater for using later.

Let’s Recapitulate

Fill in the blanks.

1. About ______________ of the earth is covered with water.
a. 1/4 th b. 3/4 th c. 1/2

2. The amount of water vapour present in the atmosphere is called ______________.
a. evaporation b. fog c. humidity

3. ______________ is a thick layer of clouds made up of tiny drops of water.
a. Dew b. Mist c. Frost

4. ______________ is the easiest method to purify water.
a. Boiling b. Decantation c. Evaporation

LET’S
REVISE

• The condition of atmosphere around us at a specific time is called weather.

• The part of the earth which is close to the sun has warmer and longer days.
• The earth revolves around the sun on its own axis and takes 365 days and 6 hours to

complete one cycle.
• Seawater does not heat up as quickly as land during the day. The air gets heated up

because of the heat of the land.
• Water continuously changes its form from liquid to vapour in nature. This works as a

continuous cycle.
• Boiling, sedimentation, decantation, filtration and chlorination are the methods to
purify the water.

Let’s Pronounce Together

revolution rotation humidity filtration
chlorination sedimentation decantation

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