This is explained by the kinetic theory of matter. Read more in the Bitesize guide to the particle model and density and the energy, temperature and changes of state study guide. In a system ...

One can see that the ultimate scope of the descendent of the kinetic theory of gases must be the whole field of the properties of matter in bulk, derived from the atomic constitution of matter and ...

Thus Book ii., on heat, contains a chapter on the kinetic theory of matter; while the introduction to Book iv., electricity and magnetism, deals with the properties of the ether, and in the ...