Monday, 8 September 2014

CONDUCTION, CONVECTION


               CONDUCTION, CONVECTION

1. Equal amounts of hot coffee are poured into two cups. The two cups are exactly the same shape and size but one is made of polystyrene and the other is made of tin.
(a) Which cup will keep the coffee hotter for longer?

…………………………………………………………………………………………………….…

(b) Why is this? 

……………………………………………………………………………………………………….

2. Complete the sentences using one of the following words for each space:

conduction                         convection                         insulator                              conductor

(a) a metal is a better  …………………………  of heat than plastic

(b) hot air rising up a chimney is called  …………………………………………………………..

(c) Plastic is a good   ………………………………………………………………………….

(d) heat is transferred along a metal rod by  …………………………………………….………..

(e) a thick woolly jacket round a hot water cylinder is a good   …………………………...…….

(f) iron is a better  …………………………….  of heat than air

3. The handle of a saucepan should be made of   ………………………………….. because it

is a bad conductor of heat.

4. You stir some tea with a plastic spoon and a metal spoon (both spoons are the same size). Which one will you feel getter hotter first.

……………………………………………………………………………………………………….

5. Heat flows along a plastic rod because the   ……………………………………. in the rod

vibrate and collide with each other.

6. Write down four places where convection is important in a home:

(a) …………………………………………………………………………………………………

(b) …………………………………………………………………………………………………

(c) ………………………………………………………………………………………………….

(d) ………………………………………………………………………………………………….