That basic concept is common sense, while a major hang-up is in knowing the difference between heat and temperature . There are 3 modes of heat transfer- Conduction, Convection, and Radiation . Heat Heat is vibration of molecules. Lots of vibration feels hot to the touch. No vibration feels extremely cold.
Molecules are like teenagers with peer pressure.
Blending in and being accepted is what counts. They like to vibrate as much as the next guy. They do not like to vibrate more than the next molecule, and they do not like to vibrate any less. If all the other molecules jump off of a bridge, then this molecule will do it too. Metal molecules only know their immediate neighbors because they don t move about.