64
Observe Figure 4 and ll in the blank spaces with the following words:
evaporation, condensation, rainfall.
Let’s recap how rain is formed:
• Air that contains water vapour rises in the atmosphere*.
• On rising the air cools down.
• As the air cools down, the water vapour condenses.
• On condensing the water vapour changes into tiny water droplets.
• The tiny water droplets form clouds.
• The tiny droplets join together and become big and heavy enough to
fall as rain.
How is rain formed?
Water which evaporates from seas and oceans turns into water vapour.
The water vapour in the air cools down and condenses to form clouds from which rain falls.
Rainwaterfallsontheearth’ssurface.Itmayowbacktotheseasandoceans.
This is the water cycle.
Sea
Mouth
River
River
Source
Plain
Coast
Mountain
fig. 4 THE WATER CYCLE
For rainfall to occur, air containing water vapour should rise.
Atmosphere:
thick layer of
air surrounding
the earth
*
2.0
ACTIVITY
rainfall topic 2 topic 2