Page 134 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

• Climate Regulation: They help balance temperatures by distributing heat and

moisture, influencing local weather patterns.

G. Long-answer questions
1. With the help of an experiment show that hot air is lighter and it rises upward.

Ans. We can show that hot air is lighter and it rises upward by the following experiment.
Aim: To show that warm air rises up.

Principle: Warm air expands and becomes
lighter due to which it rises up and exerts

pressure in the upward direction.

Material required: Paper bags, thread,
stick or beam, candle and matchstick.

Procedure:
• Take two paper bags and tie them on a stick using a thread as shown.

• Keep a burning candle below one of the bags at a safe distance and observe
carefully.

Observations: You will observe that the paper bag below which the candle was
placed rises up while the other bag moves down. The beam or the stick tilts too.

This happens because the air above the candle flame becomes warm and rises up
pushing the paper bag higher. This proves that hot air rises up.

2. State an experiment to show that air exerts pressure.
Ans. The following experiment shows that air exerts pressure.

Aim : To show that air exerts pressure.
Materials Needed: A glass, water, and a piece of stiff paper or cardboard.

Procedure:
• Fill the glass with water.

• Place the piece of paper or cardboard over the mouth of the glass, ensuring it
is completely covered.

• Hold the paper in place and quickly invert the glass.
• Carefully remove your hand from the paper while keeping the glass upside

down.
Observations: The paper stays in place, holding the water inside the glass. Air pressure

is exerted on the paper from below, which is greater than the pressure exerted by
the water inside the glass, preventing the paper from falling and keeping the water

inside. This demonstrates that air exerts pressure.
3. How do cyclones affect the environment?

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