It is heat transfer in Solids. The atoms are linked by forces so the kinetic energy can be passed on from one to another. These forces are called bonds.
Supposing you heat a metal pan full of soup. If you left your metal spoon inside and went of to go to the toilet or something then you came back five minutes later you would find that the spoon would be quite hot because the heat has passed on from particle to particle through these bonds and because metal has electrons it makes it a good conductor of heat. If however you had a wooden spoon then when you came back you would find that it is not hot because Wood actually has no electrons.
Supposing you heat a metal pan full of soup. If you left your metal spoon inside and went of to go to the toilet or something then you came back five minutes later you would find that the spoon would be quite hot because the heat has passed on from particle to particle through these bonds and because metal has electrons it makes it a good conductor of heat. If however you had a wooden spoon then when you came back you would find that it is not hot because Wood actually has no electrons.