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प्रश्न
We blow to cool hot things as well as to warm them. Give examples of each.
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उत्तर
Example, when we blow to cool hot things:
- A cup of tea
- any hot food etc.
Example when we blow to warm a cold thing. Our hands in the winters.
APPEARS IN
संबंधित प्रश्न
Miya Balishtiye was confused when he saw the woodcutter blowing on his cold hands to make them warm and on the hot potatoes to cool them.
- Have you warmed your hands in winter by blowing on them when they are cold? How does it feel?
Have you ever burnt your tongue when you ate or drank something that was too hot? How do you cool some food when it is too hot?
If you were to cool these three hot things – dal, roti, rice – in which ways would you do so?
Take a glass. Bring it near your mouth and blow hard on it. Do this two or three times. Does the glass look hazy?
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.
Can you understand from the movement of the snake - if the air is moving upwards or downwards?
