Why Is Glass Clear? 🪟

Morning Transparent people!

Have you ever wondered why glass is see-through?

And why… we’re not?

Well wonder no longer, because I have the answer!

But first, you gotta understand a little something about atoms.

See, the thing about atoms is that they are mostly… made of nothing.

If an atom were the size of New York City, like this:

The nucleus bit in the centre would be the size of… a basketball.

Yeah, really.

This means atoms are like 99.9999999999996% empty nothingness.

So that raises the question, why isn’t everything transparent? Surely, any light would just pass right on through that empty nothingness.

Well, what actually happens is this.

Take a lump of iron as an example.

If a photon (aka light particle) were to be shot at the iron atoms with the perfect amount of energy, one of the electrons would ABSORB this energy.

This is what makes that lump of iron visible.

But if that photon doesn’t have the right amount of energy, it would pass right on through. 

What do I mean by “amount of energy”? 

Well, light is a spectrum.

Some light waves have higher frequencies and higher energies than other light waves.

And electrons have this thing where they only absorb light if the photon has the correct amount of that energy.

The thing is, the atoms that make up glass require too much energy for any light in the “visible light“ section of the previous image.

Therefore, the photons just pass on through. 

Making it… transparent!

However, Ultraviolet light (higher energy light) does in fact have the correct amount of energy.

And thus when an Ultraviolet photon passes through glass, it DOES get absorbed by the electrons.

Which is why it's so hard to get sunburn through glass. The UV can't get through.

Pretty cool right?

Basically, transparency happens when the light is too weak or too strong for the electrons.

This means that when visible light hits our flesh, it gets absorbed!

So we can see it.

That's why we’re not transparent.

But if we hit you with light that's a little stronger, like X-rays suddenly you become… transparent!

Stay Cute,
Reece, Henry & Dylan 🌈

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