# Experiments with Water

## Overview

This chapter uses Ayesha's daily life to explore the properties of water—floating and sinking, dissolving, and evaporation—through engaging observations and hands-on experiments. It also touches on the historical context of salt production and the Dandi March, blending science and social learning.

## Key Topics Covered

### 1. What Floats – What Sinks?

- Ayesha observes that when a puri is put in hot oil, it first sinks, then floats as it puffs up.
- Soap cases float while soap sometimes sinks.
- Some metal objects sink (e.g., needle), while large objects like a steel plate or ship float due to shape.
- Children are encouraged to test various objects like bowls, nails, matchsticks, bottles, and foil to see if they float or sink.

### 2. Group Activity: Sink or Float

- Children perform an experiment using a large pot of water and several items:
- Empty bowl
- Pebbles in bowl
- Iron nail
- Matchstick
- Plastic bottle (empty, half-filled, full)
- Aluminium foil (flat, balled, cup-shaped)
- Soap (alone and on plastic plate)
- Ice

- Observations are noted on which items sink or float.
- Students are prompted to think about why some objects float and others sink, even if they are heavier.

### 3. Salt and Floating

- Ayesha accidentally adds too much salt to boiling water and notices that eggs begin to float.
- A follow-up experiment: add salt gradually to water with a lemon to see it float.
- Children conclude that the salt increases the water's density, making some objects float.

### 4. What Dissolves and What Does Not?

- Hamid is asked to dissolve sugar for a sweet dish and wonders how to make it dissolve faster.
- Children are encouraged to test:
- Salt
- Soil
- Chalk powder
- Milk
- Oil

- They record if the substance dissolves and what it looks like after 2 minutes.
- Comparison: salt dissolves fully while chalk or soil does not.
- Concept: dissolved materials disappear but are still present in the water.

### 5. Does Oil Dissolve?

- Ayesha and Hamid argue whether oil dissolves in water.
- Observation: oil forms tiny visible droplets and does not mix like sugar or salt.
- Conclusion: oil does not dissolve completely and separates on standing.


### 6. Racing Drops

- Ayesha experiments by putting drops of oil, water, and sugar solution on a tilted surface (lid of tiffin box).
- Observes:
- Water drops slide fastest
- Sugar solution is slower
- Oil moves the slowest
- Insight: Different liquids move differently due to their thickness or "stickiness".

### 7. Where Did the Water Go?

- Ayesha’s mother forgets boiling water on the stove—some of it disappears.
- Children are encouraged to think about:
- Where the water went (evaporated into air)
- Why sun is used to dry things like mango jelly
- Other household items dried in the sun (e.g., papad, pickles, clothes)

### 8. Dandi March and Salt

- Introduces a historical event from 1930:
- Gandhiji’s protest against British salt tax.
- People were not allowed to make their own salt.
- Gandhi led a long walk (Dandi March) to the seashore in Gujarat.
- Explains how salt is made:
- Sea water collected in shallow beds.
- Water evaporated using sunlight.
- Salt remains after water dries.

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## New Terms and Simple Definitions

| Term | Simple Definition |
|---------------|------------------|
| float | To stay on top of the water |
| sink | To go to the bottom of the water |
| dissolve | To mix completely in water and disappear |
| density | How heavy something is for its size |
| evaporation | When water turns into gas and disappears |
| Dead Sea | A very salty sea where people can float easily |
| salt | A white crystal used to add taste to food |
| mixture | A combination of two or more things |
| oily | Something that feels slippery like oil |
| Dandi March | A protest march led by Gandhiji against British salt laws |

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## Practice Questions

### Easy (3)
1. **What happens when you put a puri in hot oil?**
*It first sinks, then floats as it puffs up.*

2. **What happens when too much salt is added to water with a lemon?**
*The lemon starts to float.*

3. **Name two things that dissolve in water.**
*Salt and sugar.*

### Medium (2)
4. **Why did the aluminium foil float when spread out but sink when pressed into a ball?**
*Because the shape affects how water pushes it up; spread shape holds more air and floats.*

5. **What did Ayesha observe about the soap case and soap in water?**
*Soap case floated, and sometimes even floated with soap in it.*

### Difficult (3)
6. **How does the Dead Sea help people float even if they don’t know how to swim?**
*It is so salty that the water becomes very dense and pushes the body up.*

7. **What differences did you observe between salt water and chalk powder in water after 2 minutes?**
*Salt disappears (dissolves), chalk powder settles at the bottom.*

8. **Why do water, oil, and sugar solution slide at different speeds on a surface?**
*Because they have different thicknesses (viscosity).*

### Very Difficult (2)
9. **How does evaporation help in making salt?**
*When sun heats water, it turns into vapor and disappears, leaving salt behind.*

10. **Why was the Dandi March important for India’s independence movement?**
*It was a peaceful protest against unfair salt laws and showed people’s right to nature’s resources.*

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