ELI5: Explain Like I'm 5

Spin angular momentum of light

Light is made up of tiny, tiny particles called photons. Photons have something called spin angular momentum. This means that photons have a certain amount of "spin" like a tiny spin-top, and this spin has a certain amount of momentum that can be measured. Photons with a lot of spin and momentum can act like tiny bullets and can be used to do things like take pictures and send signals.