# Blow Hot, Blow Cold

## Overview
In this chapter, students explore the concept of temperature and the movement of air through a humorous and curious story featuring a woodcutter and a character named Mian Balishtiye. The chapter links daily experiences such as blowing on hands, food, or spectacles to scientific ideas like hot and cold air, condensation, and air movement.

## Key Topics Covered

### 1. Story Summary: The Curious Mian Balishtiye
- A woodcutter goes into the cold forest and keeps blowing on his hands to keep them warm.
- Mian Balishtiye secretly observes him and is puzzled by his actions.
- Later, the woodcutter blows on a fire to make it burn and on a hot potato to cool it down.
- Mian is shocked that the same person can blow to both warm and cool things—he believes the woodcutter must be a ghost!
- The story ends with the message: some things may seem impossible but are true.

### 2. Observations with Breath
- Blowing on hands in winter makes them warm because the air from our mouth is warmer.
- Blowing on hot food cools it because it helps the hot air and steam escape quickly.
- Activities compare breath temperature at different distances from the mouth.

### 3. Scientific Activities and Experiments

#### A. Using Warmth of Breath
- Folded cloth becomes warm when blown on.
- Glass or mirror turns hazy due to moisture in the warm breath.
- Spectacles can be cleaned using moist breath.
- Demonstrates that breath contains water vapor.

#### B. Paper Whistle and Sounds
- Students make a whistle from paper and explore how blowing makes sound.
- Compare different objects that make whistling or musical sounds (balloons, leaves, pen caps).

#### C. Musical Instrument Exploration
- Children explore how different instruments (flute, guitar, dholak, been) produce sound.
- They are encouraged to identify instruments by sound alone.

#### D. Air Flow and Movement
- A spiral paper snake is used to detect air direction.
- Hot air rises, causing the snake to rotate clockwise.
- Cold air sinks, moving the snake in the opposite direction.

#### E. Breathing Exercises
- Count the number of breaths in a minute before and after physical activity.
- Use a rubber tube and funnel to hear the heartbeat (similar to a stethoscope).
- Chest expands during inhalation and contracts during exhalation.

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## New Terms and Simple Definitions

| Term | Simple Definition |
|------------------|------------------------------------------------------------------------|
| breath | The air you take in and blow out through your nose or mouth |
| condensation | Water droplets that form when warm air touches something cold |
| whistle | A sound made by blowing air through small openings or instruments |
| funnel | A tube that is wide at the top and narrow at the bottom, used to guide air or liquid |
| spiral | A shape that winds in a circle like a spring or snail shell |
| moisture | Water in the form of tiny drops in the air or on surfaces |
| stethoscope | A tool doctors use to listen to your heartbeat or breathing |
| temperature | How hot or cold something is |
| evaporation | When water turns into steam or vapor |
| instrument | A tool used to make music, like a flute or drum |

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## Practice Questions

### Easy (3)

1. **Why did the woodcutter blow on his hands?**
*To warm them up because it was cold.*

2. **Why did Mian Balishtiye get confused?**
*Because the woodcutter used his breath to warm and cool things.*

3. **What happens when you blow on a hot potato?**
*It cools down because the air removes the heat.*

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### Medium (2)

4. **What would happen if you eat something very hot without cooling it?**
*You might burn your mouth or tongue.*

5. **How can you use your breath to clean your spectacles?**
*Blow on them to make them moist, then wipe with a cloth.*

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### Difficult (3)

6. **Explain why the paper snake moves when held above a hot object.**
*Hot air rises, pushing the spiral paper, causing it to spin.*

7. **Why does glass or a mirror become hazy when we blow on it?**
*Warm breath contains water vapor that turns into tiny droplets on the cold surface.*

8. **Why did Mian Balishtiye think the woodcutter was a ghost or djinn?**
*Because he thought it was impossible to blow hot and cold air from the same mouth.*

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### Very Difficult (2)

9. **How does the activity with the funnel and tube help us hear a heartbeat?**
*The funnel collects sound, and the tube directs it to our ears, just like a stethoscope.*

10. **How can you test whether the air you blow is hot or cold compared to the surrounding air?**
*Blow on your hand at different distances or blow on a glass to see if it gets hazy.*

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