How fire works

If a substance is flammable, heating it to its "ignition temperature" will create a combustion reaction, and the substance "burns"; more specifically "the compound molecules break apart, and the atoms recombine with the oxygen to form water, carbon dioxide and other products."

The light we see produced from fire is created from "the rising carbon atoms (as well as atoms of other material) emit[ting] light."

Source: http://science.howstuffworks.com/fire1.htm

How a CD Burner works

A CD burner works by dulling the reflective surface of a burnable disc. When the laser reads the disc, the light is projected at an angle that should reflect back at a receiver. When the laser hits the reflective surface, it's read as a "1." When the light is dulled and therefore not reflected back, it's read as a "0."

Firefly sight

Fireflies/lightning bugs do not see blue light.