Why does oil sometimes get weird colors in it. It will shine blue, purple, or yellow even. It kind of looks like the colors you get when you case harden metal.

Question

Why does oil sometimes get weird colors in it. It will shine blue, purple, or yellow even. It kind of looks like the colors you get when you case harden metal.

In: Chemistry

Answer 1

It has to do with how thin film diffraction splits up white light into seperate rays. Each color has its own unique wavelength (between roughly 400 and 750 nm) and when white light (light of all visible wavelengths) enters certain mediums the different wavelengths reflects by different measures. This is part of what happens in a rainbow as well as in a crystal.