CONDUCTION

Tuesday, September 2, 2008

CONDUCTION
Conduction is a process of thermal energy transfer without any flow of the material medium.
For an example, how heat is transferred from the flame of a stove, to the whole pot, while cooking. Thermal energy is transferred without any movement of the material medium.
As different materials conducts heat at different rates, materials which conducts heat at a faster rate are called conductors of heat, whereas materials which conducts heat at a slower rate are called insulators.

How it worked in solids??
As all solids are made up of molecules, when molecules of an are is heated up, it vibrates vigorously and thus collides with the neighbouring molecules, making them vibrate as well. Thus, kinetic energy of the vibrating molecules at the hot are is transferred to the neighbouring particles.

The difference in metals and non-metals are that metals contains many free electrons which move randomly between atoms, while non-metals do not have such free electrons. These free electrons gain kinetic energy and move faster as a result causing the cool areas to heat up faster: free electrons diffusion.

And how it worked in liquids and gases??
Although thermal energy can be conducted from hot regions to cool regions in liquid and gas, however, it is inefficient. Particles in liquids and gas are spaced further apart than those in solids, therefore causing collisions between particles to be less frequent and vigorous. Transfer of Kinetic energy is therefore slowed down, and explains why air is a worse conductor as compared to water, and water being a worse conductor than a solid.


Posted by xiaowei aunty at 10:44 PM