While contemplating the food value of a slice of ham, you notice a rainbow of color reflected from its moist surface. Explain its origin.
At the moist surface there will be a thin layer of water, which will behave like a thin film. Hence depending on the thickness of the water layer, some colour will interfere constructively and some destructively. And since the thickness of the water changes because of the rough surface of the ham, we see a rainbow color.