Good conductor of electricty => Good conductor of heat?

In summary: It's just that it doesn't have a lot of electrons so it doesn't distribute the heat as well as other materials.
  • #1
jobsism
117
0
I've noticed that almost every good conductor of electricity, is also a good conductor of heat, except for certain exceptions like Graphite. Why is this so? I can't seem to associate electron flow with heat conduction.
 
Physics news on Phys.org
  • #2
Check the Wiedemann-Franz law that explains how the ratio of thermal to electrical conductivity in metals is almost a constant
 
  • #3


Gordianus said:
Check the Wiedemann-Franz law that explains how the ratio of thermal to electrical conductivity in metals is almost a constant

Ah, thank you for your reply! I understand the law, but I'm still confused on how electrical conduction contributes to thermal conduction. I'm thinking, that in good electricity conductors, there are more number of free electrons, the motion of which causes them to acquire higher thermal energy. But is this what allows higher heat conduction?
 
  • #4


jobsism said:
Ah, thank you for your reply! I understand the law, but I'm still confused on how electrical conduction contributes to thermal conduction. I'm thinking, that in good electricity conductors, there are more number of free electrons, the motion of which causes them to acquire higher thermal energy. But is this what allows higher heat conduction?

I confirm it's about the electrons.
In metals the valence band and the conductance band are overlapping.

In any material the internal energy (the heat) redistributes over the available degrees of freedom. In a metal heat redistributes to the electron population too. The nature of a metal is that the electrons can have any energy within a certain extended band. In an insulator only a big jump in energy will free an electron to move away from its current atom. At normal temperatures the available energy is not enough for that jump, so there is high electric resistence.

Coming back to metals: part of the total internal energy is in the electron population, and the electrons can move freely through the metal, transporting the internal energy to other parts.


For more information look up things like 'valence band' and 'conductance band'.
 
  • #5
Thank you, Cleonis! I think I understand now.
 
  • #6
Not always one-to-one the other way though. The best thermal conductor is diamond and it's a great insulator. Sapphire is similar.

Actually graphite is an ok conductor of both current and heat.
 

1. What is the relationship between being a good conductor of electricity and being a good conductor of heat?

Both qualities are related to the ability of a material to transfer energy. In the case of a good conductor of electricity, it allows the flow of electrons easily, while in a good conductor of heat, it allows the transfer of thermal energy.

2. Can a material be a good conductor of electricity but a poor conductor of heat, or vice versa?

Yes, it is possible. For example, materials like copper and silver are excellent conductors of both electricity and heat, while materials like rubber and wood are good insulators of electricity but not of heat.

3. What factors determine whether a material is a good conductor of electricity and heat?

The atomic and molecular structure of a material plays a significant role. Materials with a highly ordered and dense structure tend to be good conductors of both electricity and heat, while those with a more disordered and loosely packed structure are usually poor conductors.

4. Are there any materials that are good conductors of heat but poor conductors of electricity?

Yes, some materials like diamond and silicon carbide have a high thermal conductivity but a low electrical conductivity. This is due to the nature of their atomic bonds, which allow for efficient heat transfer but not for electron flow.

5. How are good conductors of electricity and heat used in practical applications?

Good conductors of electricity are essential for the functioning of electronic devices, electrical wiring, and power transmission. Good conductors of heat are used in applications such as cooking, heating, and cooling systems. They are also crucial in industries that require precise temperature control, such as in metallurgy and chemical manufacturing.

Similar threads

Replies
14
Views
964
Replies
3
Views
378
Replies
1
Views
1K
  • Electromagnetism
Replies
7
Views
888
  • Electromagnetism
Replies
14
Views
1K
  • Electromagnetism
Replies
2
Views
753
Replies
2
Views
647
Replies
11
Views
2K
Replies
14
Views
2K
Replies
12
Views
3K
Back
Top