How Einstein discovered that light is a particle and won a Nobel for it

The story of how Planck and Einstein discovered that light comes in packets

It’s no mistery that if you heat something really hot it starts to shine, that’s why the stars shine and how your home light bulb works.

Maybe you even know that there is light (or to be precise electromagnetic radiation) that we can see and other light that we cannot see. For example there are the infrared rays that we feel as heat, that’s why you feel warm when you face the fire.

But scientists are precise people, for them it’s not enough to know that hot bodies emit light, they also wanted to know how much light.

At the beginning of the 20th century this question was driving all the scientists crazy: they had tons of data collected in countless experiments, they graphed the light emission in the most accurate way possible, but still they couldn’t explain what they were seeing.

Nobody could come up with a physical explanation for the behaviour of hot bodies, the particularly nasty bit was ultraviolet emission, they even called it…