What causes the rainbow-like dicoloration when a piece of metal is heated?

Question

I noticed it when I was doing an experiment with a 3,000 watt bulb (projection) and a magnifying lens.When I focused the beam on to a piece of tin, it nearly burned a hole in it! There was a small, greyish patch that was very thin and brittle and it had rings of many different colors around it, like a dartboard. What causes the colors? Light?

Answer 1

It is caused by electrons being emitted...(aka photons aka light) but certain metals give off certain colours according to their wavelenght...and according to the line spectrum....