What Causes Metals to Conduct Heat?

In summary, metals have free electrons that allow them to easily transmit heat energy. Diamond has strong covalent bonds which makes it very efficient at doing so.
  • #1
at2341
10
0
Hi,

I understand what make metal a conductor of electricity, but what allows it to conduct heat? Is it that it does not absorb heat because it's electrons are easily liberated?
 
Science news on Phys.org
  • #2
What do you mean by " it does not absorb heat"? Metals do absorb heat and even faster than those can not conduct heat well. The reason that metals conduct heat well is the liberated electrons.
 
  • #3
at2341 said:
Hi,

I understand what make metal a conductor of electricity, but what allows it to conduct heat? Is it that it does not absorb heat because it's electrons are easily liberated?

Remember what "heat" is in thermodynamics. It is nothing more than "energy of vibration".

In metals, there are 2 different ways for them to absorb heat: via lattice vibration, and via the free electron gas. Most of the heat is absorbed by the lattice vibration because the free electron gas has a very low specific heat. However, the ability of metal to conduct heat very well and transfer it very efficiently throughout its volume better than an insulator is due to these very mobile conduction electrons. So these electrons can carry the heat energy faster throughout the metal.

So how come an insulator doesn't? Other than the lack of these free conduction electrons, insulator also tends to have an amorphous crystal structure (unlike metals that tend to be crystalline), or highly polycrystalline (not large single-crystals like metals). When you have something amorphous or polycrystalline, the vibrations in one part of the material do not transfer well to other parts. So the heat transfer is very slow in such material.

Zz.
 
  • #4
About that, why diamond has a very high heat conduction coefficient? I assume it has a very "efficient" way of propagating phonons, and if this is true, why?
 
  • #5
...why diamond has a very high heat conduction coefficient? I assume it has a very "efficient" way of propagating phonons, and if this is true, why?

The covalent bonds in diamond are strong. The crystal structure consists of two interpenetrating face-centered-cubic lattices (this is called a diamond cubic structure), which means that each carbon atom has tetragonal coordination. The result is a 3-D arrangement of bonds that is strong in all directions (in contrast to graphite, which is characterized by a 2-D molecular arrangement).

Diamond can be thought of as a single giant molecule that is held together tightly. Its strong bonds and particular crystal structure lead to high stiffness, low thermal expansion, high sublimation point, brittle fracture, and finally, high thermal conductivity.
 
  • #6
Mapes said:
...why diamond has a very high heat conduction coefficient? I assume it has a very "efficient" way of propagating phonons, and if this is true, why?

The covalent bonds in diamond are strong. The crystal structure consists of two interpenetrating face-centered-cubic lattices (this is called a diamond cubic structure), which means that each carbon atom has tetragonal coordination. The result is a 3-D arrangement of bonds that is strong in all directions (in contrast to graphite, which is characterized by a 2-D molecular arrangement).

Diamond can be thought of as a single giant molecule that is held together tightly. Its strong bonds and particular crystal structure lead to high stiffness, low thermal expansion, high sublimation point, brittle fracture, and finally, high thermal conductivity.

Corundum (aluminum oxide), e.g., has very strong bonds too (yes, not so strong, but however very strong) but it's 30 times less conductive than diamond and at least 6 times less conductive than aluminum. Why? Your explanation doesn't seem so good.
 
Last edited:
  • #7
OK, let's hear your explanation. :smile: To be fair, it should explain diamond's high thermal conductivity, plus an experimental fact of my choosing, to be disclosed after you reply.
 
  • #8
lightarrow said:
About that, why diamond has a very high heat conduction coefficient? I assume it has a very "efficient" way of propagating phonons, and if this is true, why?

Photons and heat are different concepts.
 
  • #9
clouded.perception said:
Photons and heat are different concepts.

Phonons and heat are very closely linked.
 
  • #10
clouded.perception said:
Photons and heat are different concepts.

As are heat and temperature. It's a bit inaccurate to say an object possesses "heat," because heat is one way of transferring energy (the other being work). If a metal is "hot," it just has a high average molecular kinetic energy which translates into a high temperature in human tactile terms.
 
  • #11
Mapes said:
OK, let's hear your explanation. :smile: To be fair, it should explain diamond's high thermal conductivity, plus an experimental fact of my choosing, to be disclosed after you reply.
That's perfect!
One little note, anyway: if I had that answer, I wouldn't have asked the question in my post N. 4. :smile:
 

What is metal conduction?

Metal conduction is the process by which heat or electricity is transferred through a metal material.

How does metal conduction work?

Metal conduction works through the movement of free electrons within the metal material. When heat or electricity is applied, these electrons transfer the energy from one atom to another, allowing for the conduction of heat or electricity.

Why are metals good conductors?

Metals are good conductors because they have a high number of free electrons that are able to move easily through the material, allowing for efficient transfer of heat or electricity.

What factors affect metal conduction?

The factors that affect metal conduction include the type of metal, its temperature, and its physical structure. Different metals have varying numbers of free electrons, and temperature can affect the speed at which these electrons move. The physical structure of the metal can also impact how easily electrons can move through it.

Can metal conduction be controlled?

Yes, metal conduction can be controlled through various methods such as adding insulating materials, adjusting the temperature, or altering the physical structure of the metal. These methods can help to decrease or increase the level of conduction in a metal material.

Similar threads

  • Thermodynamics
Replies
6
Views
399
Replies
7
Views
177
Replies
2
Views
443
Replies
17
Views
1K
  • Thermodynamics
Replies
2
Views
681
  • Thermodynamics
Replies
5
Views
1K
  • Thermodynamics
Replies
28
Views
1K
Replies
20
Views
1K
Replies
1
Views
855
Replies
2
Views
989
Back
Top