Page 233 - Primary Five Science

1. Conduction

Heat travels through solids by a process called conduction.

In solids heat is transferred from one heated molecule to an-

other. This transfers heat until the whole solid object is heated.

Examples

 Touching a stove and being burned

 Ice cooling down your hand

 Boiling water by thrusting a red-hot piece of iron into it

(Water heater)

.
Importance of conduction

It helps us to cook

Conduction of heat enables us to iron our clothes.

2. Convection

Heat travels through liquids and gasses by a process called

convection.

Heat in liquids and gases travels in form of convectional cur-

rents.

The particles which are heated become light and move up-

wards while the cooler and heavier particles move down-

wards.

Example

Heating water to boil

The particles nearest to the source of heat are heated and be-

come light and move upwards while the cooler and heavier

particles move downwards.