Why is it a good conductor of electricity a good conductor of heat?

Answer 1

Not all are.

The general rule among metals is that the better it is for conducting heat, the better it is at conducting electricity.

But for things that are not metals, this is not the rule. Diamonds are astonishingly good at conducting heat, much better than copper, but they are terrible at conducting electricity and are considered to be insulators.

Answer 2

One idea as to why metals are good thermal and electrical conductors is that they have more free electrons to allow them to "conduct" electricity and thermal energy. Another idea is that some of the electrons in the metallic matrix are in energy levels that overlap what is required for an electron to be in the conduction band for that material. The overlap means that electrons are already in energy levels that are sufficiently high for them to support current flow. Because they are, they will do that (support current flow) when a voltage is applied. And if a thermal differential exists, heat will move well for a similar reason.

Answer 3

This is usually true for metals. It is not usually true for nonmetallic substances, however. Diamonds conduct heat much better than copper, but are electrical insulators.

Answer 4

They aren't necessarily good conductors of both (like diamond, which is a good conductor of heat, but not electricity) Graphite is one that is both, but most of them are metals.

Answer 5

The electrons in electrical conductors also absorb and carry heat, thus are good thermal conductors also.

Answer 6

Metals have lots of electrons that are relatively free to move around. These conduct electricity; and much of the heat conduction is also due to these electrons.