Page 174 - New Medley 3 Semester 2

What happens? Where has the water from the hanky

gone?

When water is heated, it turns into a gas. e gaseous

form of water is called water vapour or steam. It is

colourless and has no smell.

e process of changing of water into water vapour
on heating is called evaporation. On heating, water changes
into water vapour (gas)

erefore, when we leave wet clothes in the sun, they
become dry because water in them becomes hot and changes into water vapour
which is blown away by air.

Take some cold water in a glass and leave it on a table for 15 minutes. Look at

the glass from outside. Where have these water droplets come from?

e water vapour cools down when it comes in contact with a cold surface. On
cooling, the water vapour changes back into water. e changing of water vapour

into water on cooling is called condensation.

Can you recall some situations where you can see condensation?

WATER CYCLE

e sun heats the water of oceans, lakes, rivers, ponds and even puddles in your
garden. As a result, water evaporates. When water evaporates, it rises up into the

sky. en, it cools down and forms water droplets. ese water droplets come

together and form clouds.

Water cycle
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