Video Transcript
Which of the following materials is likely to have the highest thermal conductivity? a) Glass, b) plastic, c) wood, d) copper, e) felt.
When we’re talking about highest thermal conductivity, that means we wanna choose the material that’s most capable of transmitting thermal energy. A very practical way to figure this out would be to heat up a sample of each of these materials and then touch it with our hand and see which one feels hottest. Now, for safety reasons, this wouldn’t be a very good idea. But it would help us settle this question of which material has the highest thermal conductivity.
If we heat up a glass, say, in the microwave and then touch it, it will be fairly hot but not painfully so. If we heat up a block of plastic, that will gain temperature as well but not feel especially hot to our touch. Wood is actually a great example of an insulating material. If you ever held a stick with one end in a campfire and the other end in your hand, you know that wood is a great insulator or a poor thermal conductor.
But then, we get to copper, the one metal, the one conductor in this list of materials. A hot copper pan that we have been cooking in over the stove will be very painful to touch. The heat in the pan will be transmitted easily to our hand. And then, if we consider touching a hot piece of felt, that also wouldn’t do a great job of conducting heat to our hand.
Aside from the copper, every one of these materials is not a conductor. That is, it’s not classified as a material which easily transmits electric charge or thermal energy. But copper does do those things. And it does them very well.
So when we pick which material is likely to have the highest thermal conductivity, we choose copper, the one metal and the one conductor in this list of materials.
