On Mon, 22 Feb 1999 23:38:41 EST CALYK@aol.com writes:
>In a message dated 2/22/99 3:29:19 PM Central Standard Time,
><< Light moving through water or whatever also goes the same
> |speed, its just refracted.
> Do you claim that light does not go slower in water? >>
>Well, yes shine a light through water and it takes longer to get to
>destination than in a vacuum, but what I was implying, is that since
>through molecules, its path is diverted, Im not sure exactly how, but
>what I've understood. It goes the same speed it always goes, its just
>medium changes its course, thus making its destination longer than if
>wasnt a medium.
When light (electromagnetic energy) hits an electron, which is an electrically charged particle, the electron is made to vibrate. A vibrating electron in turn creates an electromagnetic field with the same frequency as the vibration. Metals are shiny because there is a cloud of mobile electrons at the surface of the metal, free to vibrate easily, so metals typically have high reflectivity. Because electrons have mass, they have inertia, so their vibration is a bit delayed (out of phase) relative to the phase of the wave fronts of light which cause them to vibrate. That, I think, is the cause of the delay as light moves through a transparent material. The wavelength of visible light is typically about 1,000 times the size of a typical simple molecule, like silicon dioxide (quartz), so the idea that the photons are delayed because they 'bounce around' as they pass through a transparent medium such as glass is seemingly not correct. It's more like a motorboat which runs slower through molasses than through water.