Page 76 - ACTIVE SCIENCE 4 TOC

The Sun Causes Winds To Blow

The heat of the sun affects the wind’s movement.
The air heats up because of the sun’s heat and so,

air gets lighter. The warmer and lighter air rises to
flow.In turn, the heavier cool air comes in to take

its place. This results in the continuous movement
of air causing winds.

How Are Clouds Formed?

The sun’s heat changes the water into water vapour. The amount of water vapour
present in the atmosphere is called humidity. As the water vapour rises high up
in the sky, it cools down and condenses into tiny droplets of water. As a result,
these droplets combine and form clouds. When these clouds get too heavy and can

no longer hold the water, they fall as rain on the earth. Therefore, the sun plays a
crucial role in changing the states of water.

A ir

Air is very important for all living things to breath. We can feel the air but we
cannot see it. It is made up of different gases and contains water vapour, dust
particles and smoke. Simple moving air is called wind. Wind which is gentle is

called breeze. Strong and fast air is called gale. Very fast and strong wind can
cause storms.

The seawater loses heat more slowly than land and it does not lose the same
amount of heat at the same time. This difference gives rise to sea breeze and

land breeze. Let us see how it
happens. Low
Pressure
Sea Breeze

During daytime, the sea does Sea Breeze High
not heat up as quickly as land. Pressure
The air above land heats up
because of the heated land. Land heats up
Being lighter, the hot air rises during day

up. To fill this space, the cool Sea water is cool during day
air from the sea blows towards compared to land
the land. The wind which blows
from sea to land during the day
is called sea breeze. Sea Breeze

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Active Science-4