Eli5: How do diamonds make light go slower ?

Question

I googled it, but i didn’t really understand.

Can someone simplify the explanation please?

Thank you 🙂

In: Physics

Answer 1

Well, this is true of any material. Light moves at a certain speed in the vacuum of space (about 3 × 10^8 km/s). But once something gets in the way, it slows down.

Think of driving on an open road. There’s nothing stopping you from driving really fast. But once more cars appear, you have to slow down. It’s sort of the same idea.

Water really slows light down, which is why things look distorted when looking at them through water.