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प्रश्न
Picture 2 - Sonu was feeling very cold. He kept blowing onto his hands. Now think and write, which will be cooler – Sonu’s hands or his breath?

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उत्तर
Sonu’s hand will be cooler. Since his hands are open to the air outside which makes it colder.
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संबंधित प्रश्न
Can you think of any other way in which you use the warmth from your breath?
For what other things do you blow air from your mouth?
Make whistles of the things given below. Write in a sequence–from the loudest to the softest whistle.
– Wrapper of a toffee
– A leaf
– A balloon
– The cap of a pen
– Any other thing
Take a glass. Bring it near your mouth and blow hard on it. Do this two or three times. Does the glass look hazy?
Count how many times in one minute do you breathe in and breathe out.
Jump 30 times. Did you feel breathless?
Can you make a mirror hazy in the same way? Can you tell by touching the mirror what made it hazy? Is the air you blew from your mouth dry or wet?
Measure your chest
– Take a deep breath in
– Ask your friend to measure your chest with a thread. Measurement ____________
– Now breathe out. Again ask your friend to measure your chest. Measurement ____________
– Was there any difference in the two measurements of your chest?
Do you want to listen to your heartbeat? Take a rubber tube as long as the distance from your shoulder to your elbow. At one end of the tube fix a funnel. Place the funnel on the left side of your chest. Put the other end of the tube to your ear. Listen carefully. Did you hear a dhak dhak sound?
Stand with this snake below a fan. Look in which direction it moves. Take this paper snake to different places and observe its movement.
