I have a question on concept of thermal energy. I’d like to have a solid definition for it. Here are some quotes:
1) Fundamentals of Physics (Halliday, Resnick & Walker), 4th edition, p. 188
”.., thermal energy, which is associated with the random motions of atoms and molecules in a body,...”
Later in the text thermal energy is used as a synonym for internal energy. Giancoli’s Physics follows the same convention. It may be appropriate in the introductory course but I suspect that there must be a difference in a closer analysis as the next quotation suggests.
2) Teaching Introductory Physics (Arnold B. Arons), p. 147
Arons lists different internal energy changes:
(a) Internal thermal energy change
(b) Internal chemical energy changes
(c) Internal kinetic energy change (includes translational and rotational energy changes)
(d) Internal potential energy changes (three types)
(e) Miscellaneous internal energy changes (e.g. sound, radiation)
What could Arons mean by thermal energy here? I have thought that thermal energy could be another name for type (c). Fundamentals of Physics seems to hint into this direction in the quotation above.
Molecules have vibrational energy as well. For some reason Arons doesn’t include this into his classification. BTW I think that Arons’ book might be the best book written on physics education.
Any suggestions?
Regards
Antti Savinainen
Physics teacher
Kuopio Lyseo High School/IB-section
Finland