Physics: Snell's window explained

It’s called snell's window. You can see this circle, where photons in the circle will escape and we see the swimming pools ceiling. However over the circle we only see the pool floor. This will happen in every pool and I can see it for myself down here. However, the lens isn't wide enough to capture snell's window sadly. But i got this awesome shot of my diving into the water.

Let me explain what it is and why it occurs.

It’s called total reflection when a photon can’t escape a medium where it goes slower (like water), to a medium where it can go faster (like air). It depends on the angle if it can escape or not.

To understand why it happens here I’ll roll with some barrels. In the blue regime the barrel roll will roll slow, and in the white regime the barrel will roll fast.

First this barrels rools, and one end sticks out causing it to rotate but finally it flies out.

Another barrel arrive with a grater angle with respect to thje surface - this causes the outer barrel to rotate for a longer time and send the barrel in to the blue medium again.

The regimes represent whater, where light can move slow. The white regime represent air where light moves much faster. Let’s imagine a duck sits here, what can it see?

The idea is somewhat the same, at smaller angles the light can escape, it might even bend.

But suddenly it will bend and align with the surface.

And any light going from over that angle will just bounce, called total reflection

So it’s easy to see why wee see a circle then. Everything within the green cone exit the water, and all the light hitting the red surface will reflect.

It’s my favorite picture, because it shows some beautiful but fundamental physics hiding in your daily life.

This video is taken from this video here:

[dfildddsspecz]

simple but good! hopefully this is enough to pass my physics exam

[Hikafujo]

Simple explaination, easy to understand, thank you !

[angelarenee]

Very nice video. I like the barrel example. I think the snell windows often look like earth's floating on space when outside filled with clouds.

[frozencookie]

Actually a great explanation. Thank you

[suyashishan]

I got a problem based in this in my grade 12 boards

[Higgsinophysics]

This video is from my main channel. (This one here)

[angelarenee]

What do you think one would look like through superfluid helium to adjacent to air/water