I have never encountered phonon before, so I am going to make a list of statements, and please be generous to point out any mistakes. Thank you. 1. There is no new physics behind the idea of phonons: it is just an alternative way of doing things. 2. When one says that there are, say, 5 phonons, it can be one of the following case: one atom oscillating with 5(h bar)w, 2 atoms with a sum of 5(h bar)w, and so on. 3. Propagation of phonons means nothing more than the exchange of energy between oscillators.