Conduction

Conduction is the process of thermal energy transfer without any flow of the material medium.







Note: Different materials conduct heat at different rates. Examples of good conductors of heat are steel, iron, etc. Poor conductors of heat is called insulator and one of them is wood.


How does it work?




Solids are made up of particles called atoms and molecules. When thermal energy is supplied to one end of the rod (using candle flame this time), the particles at that end will vibrate vigorously. They will then collide with neighbouring particles, making them vibrate as well. This is how the kinetic energy is transferred.


There is no transfer of particles but just the thermal energy. In metals, another process called free electron diffusion takes place. (Only metals have free moving electrons). This results in the faster transferring of energy as compared to other solids.


Condution in liquids and gases is much inefficient since the particles are spaced much further apart.


You should be able to:

1)Give an account of thermal energy conduction in metals and non-metals.
2)Explain why good conductors of thermal energy are also good conductors of electricity.


Question:

Is the heat transferred from a barbeque fire to a person standing in front of it a good example of heat transfer by conduction. Explain.


Answer:

Because the person and the pit is separated by air, which is a poor conductor of heat. Thus, it is not a good conductor of heat.