The Four Laws of Thermodynamics

While you are changing the state of a material say while you are melting it from solid to liquid its temperature remains constant. This has an interesting application for cooking which tells you that once you have got water to boiling point increasing the temperature further is not going to increase the heat of the stove. There are other states of matter as well for example Bosee Einstein condensates, plasmors, superfluids and some other really interesting stuff but that's an issue for another podcast.