Evaporation
Chapter Name : Matter In Our Surroundings |
Sub Topic Code : 102_09_01_05_02 |
Topic Name : Evaporation |
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Sub Topic Name : How Does Evaporation Cause Cooling? |
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Introduction
Discuss “To change from liquid to gas (to evaporate) particles need to increase kinetic energy, where does that comes from”
Pre-Requisites:
Evaporation
Activity:
Take different liquids you can find in your hope. Sprinkle each one of them over your arm at a distance from each other and tell which feels the most cold. Now induce from this which one has lowest heat of vaporization.
Real Life Question:
“What happens when you stand under a fan after bathing”
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Heat of vaporization | The particles of liquid absorb energy from liquid to vaporize. This amount of energy required is called heat of vaporization. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| A earthen pot | Fill it with water, observe closely how the outer walls becomes wet with time, discuss the reason behind this and then understand how the water cools |
Real life uses :
This cooling effect is used in desert coolers
Practical examples around us
| Examples | Explainations |
|---|---|
| we wear cotton clothes in summer | Cotton, being a good absorber of water helps in absorbing the |
What you learn in Theory:
How evaporation cause cooling
What you learn in Practice:
How liquid particles absorb heat and decrease temperature of surrounding