Scott McNay wrote: > On the other hand, this also brings up a subject that I don't understand: > heat, light (electromagnetic spectrum), electricity, and magnetism are supposedly the same, but I've yet to see/hear an explanation that passes my (as a friend of mine puts it) "common-sense test". Specifically, I don't understand how light is considered to be related to moving electrons. Can you explain, John (or someone else who has some knowledge of how these things work)? I will try. This very property is used to identify compounds scientifically in spectrophotometers. In brief, light (in the form of a photon) strikes an atom or molecule. Its energy is absorbed by an electron in that substance. The energy raises the energy level of the electron temporarily (similar to shifting it into a higher orbit). After a time, the energy is released again, causing the electron to return to its original orbit. From that drop in energy, a particle of light (photon) is emitted. Such effects are responsible for things like phosphorescence. These light particles (photons) have some of the properties of energy and some of those of matter. For example, they can strike something else and transfer energy to it. Oddly, the same photon can exert physical pressure on an object. We have a small device that demonstrates that. It is a small glass globe (partially evacuated) with a needle in the base. On the needle point is a glass cup or pivot. From it come four small arms extending outwards. Each arm supports a small flat paddle, silver on one side, black on the other. When sunlight strikes the paddles, the black side heats up more than the silver and the paddles begin to rotate away from the sun propelled by the light energy on the paddles (light pressure). -- Regards, John Durham <http://modecideas.com/contact.html?sig> ICQ number 497166248 Fax/Phone 64 4 5286786 Award winning web site at http://modecideas.com?sig Terms of trade at http://modecideas.com/lvl22.html?sig PC-HELPERS list subscribe/unsub at http://modecideas.com/discuss.htm?sig Good advice is like good paint- it only works if applied. -- -------list-services-below----------- Regards, John Durham (list moderator) <http://modecideas.com/contact.html?sig> Freelists login at http://www.freelists.org/cgi-bin/lsg2.cgi List archives at http://www.freelists.org/archives/pchelpers PC-HELPERS list subscribe/unsub at http://modecideas.com/discuss.htm?sig Latest news live feeds at http://modecideas.com/indexhomenews.htm?sig Good advice is like good paint- it only works if applied.