MORE CONDUCTION YO!

Haha the last time I ended off I didn't exactly finish about conduction, so I shall continue :D

Anyways before we procede,
here's a sample question to try! :L
To test what we've learnt from the last post :DDD

Q: Why is the rate of thermal energy transfer much faster in copper than in wood?
My Ans: Hmm, because.. Copper is a much better conductor of heat compared to wood and both conductors and insulators have different mechanisms to transfer thermal energy!

Haha yup.
Oh and another thing to note too is that, good conductors of thermal energy are usually good conductors of electricity too! Yep.

K, so now, we can move on :D
Right, so, HOW DOES CONDUCTION WORK???

Well, the explanation goes like this:
~ All solids are made up of tiny particles (atoms and molecules)
~ Thermal energy is supplied to the solid
~ the particles (atoms and molecules) at the hot end vibrate vigourously
~ These particles collide with neighbouring particles
~ Nieghbouring particles vibrate as well
~ Kinetic enery of vibrating particles at hot end transfered to neighbouring particles too

However, one thing to note would be that:
METALS contain many free electrons which move randomly between the atoms or molecules.
NON-METALS however, do not have such free electrons.

Bearing in mind this difference,
and back to what I was explaining,

So for both metals and non-metals, the particles are vibrating about their fixed positions, and this process of thermal energy transfer by conduction from the hot end to the cold end is by atomic or molecular vibrations. This process is rather slow as there is no transfer of particles.

As for metals, because of the free electrons that they have, a much faster mechanism of thermal energy transfer called free electron diffusion can take place at the same time, which explains why metals conduct heat much faster and are good conductors of heat compared to non metals.

The free electron diffusion process goes like this:
~ Metal is heated
~ free electrons in the metal gain kinetic energy and move faster
~ fast-moving electrons then diffuse and spread into the cooler parts of the metal
~ fast moving electrons collide with the atoms in the cooler parts of the metal and then transfer the kinetic energy to them
(free electrons are moving from hot end to cold end)

Which ultimately speeds up the whole process of the energy transfer.