B) To find out how this works, it is necessary to know how light comes into being: Atoms compose itself of electrons (charged negative) and protons (charged positiv) in the nuclear. The electrons move on shells around the nuclear. The more the shell is external, the higher the energy of the electron is.

If energy is introduced, for example electricity or photons (light particle), the electron „jumps“ onto a higher shell. But it can do this only for short time. After some milliseconds it „jumps“ back and releases the absorbed energy in form of a photon.

Light diffuses as waves with a certain wavelength. The photon defines a part of such a wave. The shorter the wavelength is, the higher energy of the light.

The wavelength determines the colour of the light too. Light with a long wavelength is red, with a short one it is blue. All the other colours are inbetween this. White light composes itself from all those colours.

White light is for example sunlight.

When a material absorbes light, normally he doesn´t emitt it all. A material we can see as blue only reflects the blue light. He absorbs the rest and releases it as warmth.

Another example: White material reflects nearly all the light, so it releases nearly nothing as warmth. Black material absorbs all the light. And the result you can feel: it is hotter than the white one.

Visible for us are wavelengths between 200nm and 800nm (1nm=0,000000001m).

Now to the scattering of light: When light goes through a fine grid it gets refracted. That means that every photon is moving in another direction. Photons with the same wavelength get refracted equally. A range with all the colours the light composes itself from is formed. That is what you can see as a sort of rainbow the rays of light glint in.