❤I've been used to reserving myself. Only by doing this won't I get hurt when I'm leaving.❤
❤No matter what have happened and whether you are ready or not, every next moment is gonna be a brand new start.❤
❤Whatever you do, remember that you do it for yourself, then you will not complain.❤
❤If you get tired one day, you will see my smile as long as you turn around.❤

Tuesday, 1 November 2011

Unit 5 Materials - Lesson 5

Lesson 5 Choosing Suitable Materials

We use heat insulators to keep things hot or cold. These heat insulators trap air. The trapped air cuts down heat from going through the material.

Polystyrene materials contain trapped air. They are good insulators of heat. They are used to make food containers. 

Other examples of insulators are sawdust, towels, cotton wool, coconut husks and tissue papers. These materials can be used to wrap hot things to keep them warm. They can also be used to wrap frozen things to keep them cold. 

Quick Check :
You are going for a picnic. Discuss with your friends and suggest :
1. How to keep hot food warm.
2. How to keep cold drinks cool and chill.

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