Hello, first of all, I understand, how microwave tube works but I'm interesting in how exactly the microwave heat up a things? What's the matter inside. I have heard about increasing energy of molecules of water by polarization them by micro-wave. But I have got a plate which is not from glass and it is heated up more than things on it. I suppose it is not from water :) My idea is that lattice parameter "a" of that material has resonance length for micro-waves. Or frequency of these waves is resonance frequency for such lattice. Or where is true?