# Cave of the Winds, CO - photons

1. Aug 3, 2009

### neg entropy

I was in a cave and they turned all lights off. First time I experienced total darkness. When they turned lights out, where do the photons go?

2. Aug 3, 2009

### DrChinese

Welcome to PhysicsForums!

Generally, they will be absorbed as heat.

3. Aug 4, 2009

### neg entropy

OK so the photons are absorbed into the mass of the cave. The photons are flying around, the ones that have a wavelength in the visible range, I can see. So the phtons that bounce off the rocks are the ones i see?

What determines which one get absorbed, and which ones get reflected? Well I guess utimately they all get absorbed? Some just get reflected a few times before getting absorbed?

As the photon approaches the matter- it hits either an electron, an up quark, or down quark. Will you explain what happens next? what do you mean by "absorbed"?

4. Aug 10, 2009

### alexepascual

Yes!
A simple answer would be that the ones get absorbed or reflected depends on the color of the material. A more precise answer would be that it depends on the absorption spectrum of the material, which is a detailed list of the probability of absorption for each wavelength.
The photon dissapears and its energy makes an electron to jump to a higher energy orbital. This energy is eventually all converted into kinetic energy of the atoms on the wall (thermal energy).