John G. ALBRIGHT con The heat is nomadic (English Edition)
What we call heat is actually the kinetic energy or movement energy of molecules in vibration. When a body is cold, the molecules that constitute it vibrate lazily; if the temperature rises, the deviating vibration becomes faster and the molecules possess more and more kinetic energy. If the energy of molecules deviating very large, that is to say if they are absorbed a large amount of heat, it may cause a change of state such as that observed when a solid becomes liquid or becomes gaseous.
Much of the heat, without which no life would be possible on earth, comes directly from the sun. There are several other sources of heat; electrical energy, for example, may be converted into heat, as in an electric toaster or iron. Under ordinary conditions, gases release heat when compressed and absorb as they expand. Friction also produces heat; the mechanical energy that must be deployed to overcome friction is transformed into heat. Changes in chemical nature, such as the combination of oxygen and carbon, constitute another source of heat release.