Page 84 - Innovator's Science-8

Air from surrounding areas rushes in to fill this low-pressure space and also starts rising. The Earth's
rota on makes all this moving air begin to spin. This process keeps repea ng, crea ng a powerful
spinning system of clouds, winds, and rain with very strong winds swirling around a low-pressure center.
This spinning storm is called a cyclone.
2. The figure shows trees along the sea coast on a summer a ernoon. Iden fy which side is land – A or B.
Explain your answer.

Ans. On a hot summer a ernoon, a sea breeze moves from the sea to the land. This happens because the land
heats up quickly, causing the air above it to rise and crea ng a low-pressure area. Cooler air from the sea,
where pressure is higher, moves in to take its place. If trees are shown bending from B towards A, it
means the wind is going from B to A, and A must be the land side.

3. Describe an ac vity to show that air flows from a region of high pressure to a region of low pressure.
Ans. Ac vity to show that air flows from a region of high pressure to a region of low pressure.
Materials required: Two similar balloons made of thin rubber, a drinking straw, and some thread.
Procedure:
• Insert one end of the straw into one balloon and secure it with the thread.
• Inflate the second balloon and insert the free end of the straw into the neck of the inflated balloon,
and secure it with the thread. (Ensure that the air from the inflated balloon does not leak.)

Observa ons: When an inflated balloon is connected to an uninflated balloon with a straw, air moves
from the inflated one to the empty one. This happens because the inflated balloon has higher pressure
inside, while the uninflated balloon has lower pressure. Air flows from high pressure to low pressure
un l both balloons become almost equal in size, and then the airflow stops.
4. What is a thunderstorm? Explain the process of its forma on.
Ans. i. In the rainy season, when the land heats up in hot and humid parts of India, the warm, moist air rises
because it is lighter, crea ng a low-pressure area. Cooler air from nearby high-pressure areas moves
in to fill the space. This new air also gets heated and rises, star ng a cycle of moving air or wind. As the
rising air cools, its moisture turns into ny water droplets that form clouds. These droplets join
together to become heavier and fall as rain, hail, or snow. When strong winds blow with the rain, it is
called a storm.
ii. When a storm forms, warm air can rise very high into the sky. In the cold upper parts, water droplets
turn into ice. Strong winds moving up and down make the water droplets and ice par cles rub against
each other. This rubbing creates electric charges inside the cloud. The ice par cles become posi vely
charged and move to the top of the cloud, while the water droplets become nega vely charged and
stay in the lower part of the cloud.

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