Thermal energy

Thermal energy is generated and measured by heat of any kind. It is caused by the increased activity or velocity of molecules in a substance, which in turn causes temperature to rise accordingly.

Conduction:

In heat transfer, conduction (or heat conduction) is the transfer of thermal energy between neighboring molecules in a substance due to a temperature gradient. It always takes place from a region of higher temperature to a region of lower temperature, and acts to equalize temperature differences. Conduction takes place in all forms of matter, viz. solids, liquids, gases and plasmas, but does not require any bulk motion of matter. In solids, it is due to the combination of vibrations of the molecules in a lattice and the energy transport by free electrons. In gases and liquids, conduction is due to the collisions and diffusion of the molecules during their random motion.

Convection:

Convection is the movement of molecules within fluids (i.e. liquids, gases and solids). It cannot take place in solids, since neither bulk current flows or significant diffusion can take place in solids.

Radiation:

Radiation is the transfer of energy by electromagnetic waves.

For a simple animation, please go to this website...

http://www.youtube.com/watch?v=wz6wzOtv6rs

Labels: DOne by zulfiqar(37)