Eli5: How can light travel through some materials like glas, but not through other like steel?

Question

Thought about this today and couldnt wrap my head around it. Could it have something to do with particle density?
If it has something to do with the abilty to absorb and reflect it, how does that exactly work?

Thanks in advance!

In: 6

Answer 1

Think of this like a screen door.

The glass is the screen door and light is water. The structure of the atoms of glass don’t absorb the light that hits and the photons just pass right though it. Like water though a screen door. The more things you add to that clear base glas the smaller the screen gets…the more light gets restricted. This causes the clear base to change colors.

Now, add a little of specific chemicals to the glass and you will start reflecting/absorbing specific spectrums of the light. For instance, Cobalt when added will absorb all but blue and give you transparent blue glass if added to clear glass base. Gold will produce pinks. Selenium will produce yellows…etc..etc..

Things like steal have a very tight structure that does not allow the water/light in my example to pass though.

We could go round and round about light absorption/reflection and transmission but that is not really the goal of your question. It gets out of the ELI5 scope.