NCERT solutions for Environmental Studies - Looking Around [English] Class 5 chapter 15 - Blow Hot, Blow Cold [Latest edition]

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?

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?

Can you think of any other way in which you use the warmth from your breath?

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 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?

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?

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?

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

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?

Have you seen someone blowing on their spectacles to wipe them clean? How does the air from the mouth help in cleaning the spectacles?

Take a glass. Bring it near your mouth and blow hard on it. Do this two or three times. Does the glass look hazy?

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?

Put your hand on your chest. When you breathe in, does your chest come out or go in.

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?

Put your finger under your nose. Can you feel any air when you breathe out from your nose?

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.

What was the difference in your count before and after jumping?

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?

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?

While playing, Amit hit a wall. His forehead was swollen. Didi immediately folded a scarf (4-5 times), blew on it, and kept it on Amit's forehead. Why do you think didi did this?

We blow to cool hot things as well as to warm them. Give examples of each.