Advertisements
Advertisements
प्रश्न
Have you seen someone blowing on their spectacles to wipe them clean? How does the air from the mouth help in cleaning the spectacles?
Advertisements
उत्तर
The air blown from the mouth is hot and the glass of the spectacles is comparatively colder. The hot air we breathe out contains water vapours which turn into tiny droplets of water when it comes in contact with the colder glass. This makes the glass moist and hazy.
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.
- Blowhard from your mouth onto your hands. How did you find the air from your mouth as compared to the air around you? Was it hotter, or cooler?
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?
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?
Balishtiye saw that the woodcutter was trying to cool the hot potatoes by blowing on them. What would have happened if he had eaten the potatoes without cooling them?
Have you seen people playing different musical instruments like flute, dholak, been ...., guitar, mridang, etc. Can you recognize their sounds with your eyes closed? Find out more about these musical instruments. Collect their pictures too.
Can you name some things which produce melodious or pleasing sounds when we blow into them?
Count how many times in one minute do you breathe in and breathe out.
Jump 30 times. Did you feel breathless?
Now again count how many times in one minute you breathed in and out.
You have all heard the ‘tick tick’ of the clock. Have you seen a doctor using a stethoscope to listen to our chest? What do you think she hears? Where is the sound coming from? Is there a clock inside your chest that keeps ticking away?
