Sources of Heat

Some sources of heat are:

I ) Sun

Ii ) Friction

Iii ) Chemical reaction

Iv ) Electricity

v ) Burning of fuels like wood

vi ) Conversion of other forms of energy e.g. electrical energy can be converted to heat energy.

                    Effect of Heat on Objects

     The application of heat on liquid or solid substance can result in the following

1. Rise in temperature
2. Expansion of the substance
3. Change in shape
4. Change of colour
5. Change of state
6. Formation of new substance

       Uses of Heat

Heat is used in our day to day activities

Some of the uses of heat in the home are:

1. For cooking, roasting and toasting
2. For drying objects
3. For warming  body
4. For ironing clothes

Uses of heat in industries

1. For melting metals in iron and steel industries
2. To weld (join) metals
3. In sterilization process
4. To form new substances through chemical reactions

Home-work: List five effects of heat.