Page 83 - Innovator's Science-8

Sea breeze: A day me wind that blows from the sea toward the land because the land heats up faster and the
air above it rises.
Land breeze: A nigh me wind that blows. From the land toward the sea because the land cools faster and the
air above it becomes denser.
Uneven hea ng: Different parts of earth (land, water, equator, poles) receive unequal hea ng from the sun,
causing pressure differences and wind pa erns.
Monsoon: Seasonal wind system that reverses direc on (for example, southwest monsoon brings heavy rains
to India in summer).
Thunderstorm: A storm formed by rapidly rising warm, moist air producing clouds, heavy rain, lightning and
thunder.
Lightning: A sudden discharge of electrical energy in a thundercloud or between cloud and ground, producing a
bright flash.
Cyclone: A large, rota ng storm system that forms over warm ocean waters around a low-pressure centre,
bringing very strong winds and heavy rain.
Eye (of a cyclone): The rela vely calm, clear central area of a cyclone surrounded by the violent eyewall.
Hurricane/typhoon: Regional names for the same kind of strong tropical cyclone (hurricane in the Atlan c,
typhoon in the h pacific).
Tornado: A rapidly rota ng column of air extending from a thunderstorm to the ground, usually small in size but
extremely violent.
Storm surge: A sudden rise in sea level near the coast caused by strong onshore winds and low pressure during
a cyclone, leading to coastal flooding.
Forecas ng: The use of observa ons, satellites, radar and models to predict weather and warn people about
storms.

Points to Reflect

• Air is colourless, odourless and tasteless.
• The cover of the air surrounding the earth is called atmosphere.
• The Earth is completely surrounded by air.
• Moving air is called wind.
• Wind currents are generated due to uneven heating on the earth.
• A thunderstorm is a storm accompanied with thunder.
• Once a cyclone is formed, it begins to move over the surface of ocean.

NCERT Textbook Questions (Solved)

Let Us Enhance Our Learning

1. Explain how a storm becomes a cyclone.
Ans. Cyclones are large storms that form over warm ocean water. When the ocean water heats up, the warm,
moist air above it rises high into the sky where it cools and forms raindrops. As water vapor turns into
rain, it releases heat, which makes the air rise even higher and creates an area of very low pressure
below.

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Science-8