Ch 8 explains how differences in air pressure cause wind, and how intense heating creates thunderstorms, cyclones, and tornadoes. Students also learn safety measures during storms.
When air is heated, it expands, becomes lighter, and rises (low pressure). Cooler surrounding air rushes in (high pressure to low pressure) — this is wind. Faster wind → lower pressure (Bernoulli's principle).
Cyclone: forms over warm ocean water. Warm moist air rises rapidly, creating extremely low pressure. Surrounding air spirals inward. Eye of the cyclone is calm. Tornado: a violent, rotating column of air extending from a thunderstorm to the ground. Much smaller than cyclones but very destructive.
Download: https://ncert.nic.in/textbook/pdf/gesc108.pdf | Complete book: https://ncert.nic.in/textbook/pdf/gesc1ps.zip
The eye is the calm centre of a cyclone. It is a region of very low pressure with light winds and clear skies. Around the eye is the eye wall — the most violent part with the strongest winds and heaviest rainfall.
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