Advertisements
Advertisements
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.
- Now put your hands at some distance from your mouth, and blow again. Does the air from your mouth feel warm? Why?
Advertisements
उत्तर
When the hands are placed at some distance from the mouth and the air is blown again, this time the air from the mouth does not feel much warmer. This is because, due to the distance from the mouth, the air gets mixed up with outside air and thus becomes cooler.
APPEARS IN
संबंधित प्रश्न
Fold a piece of cloth 3-4 times. Now bring it close to your mouth and blow hard on it. Did the cloth become warm?
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?
For what other things do you blow air from your mouth?
Picture 1 - Mini tried to cool her tea by blowing on it. Which do you think will be hotter – Mini’s tea or the air she blew from her 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?
We blow to cool hot things as well as to warm them. Give examples of each.
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?
