Page 72 - Innovator's Science-8

6 Winds, Storms

and Cyclones

Intended Learning Outcomes

Atmosphere Air Exerts Pressure
What causes Air Pressure? Movement of Air
Effects of Air Pressure Thunderstorms
Cyclones Hurricanes

Stepping Stones

Follow the instructions in the illustration alongside to make a paper plane using a
sheet of paper.
Make the paper plane, fly in air in your classroom and note the movement of the
plane when
a. the ceiling fan is ON b. the ceiling fan is OFF
Do you observe any difference in the two cases?

Air is colourless, odourless and tasteless. Air is all around us. We cannot see
the air. However, we can feel the presence of air. When the air blows, we
can feel it on our body, on the leaves of a tree and so on. Infact, the earth is

surrounded by a cover of air, called atmosphere . The moving of air is called
wind.

ATMOSPHERE

The cover of the air surrounding the Earth is called atmosphere . It
extends from the Earth's surface to about 1000 km. But about 99% of the
Science atmospheric air is present with 40 km from the Earth’s surface.
Bytes

Testimony The main layers of the atmosphere, from the surface of the earth
Even though we cannot upwards are :
see air, it exerts a force
strong enough to move • Troposphere • Stratosphere
giant ships, swing trees,
and li kites high in the • Mesosphere • Thermosphere
sky!

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Science-8