Hannah Fry

Just a slightly larger version than one might expect in the quantum realm.

A spin half particle, like an electron, see if you can spot this, a little bit weirder.

If you rotate it 360 degrees, it doesn't go back to the same point.

You have to rotate it twice, you have to rotate it 720 degrees for it to return to where it started.

Which is, I mean, yes,

weird it is.

This is one of the reasons why Feynman says anyone who says they understand quantum mechanics doesn't understand quantum mechanics.

This is absolutely one of the reasons why people say that the fundamental language of the universe is mathematics, because it becomes so difficult to translate these concepts into words and analogies.

and you lose something in the telling, it's all of this stuff that we're describing here essentially comes out from the structure of an equation and the way that different things relate to one another.

So yeah, there we go.

I think at some point, I know this is now the second of these questions that we've said this about, we've got sort of a nested system here where every question we ask, every question we answer reveals itself into a whole new episode.

And...

which includes more questions and therefore more episodes.

It's sort of exponential growth, the rest of science.

That's kind of what we're going for here.

But I think at some point we will do something on the very weird nature of quantum and the strangeness that happens when it comes to rotating objects.

Because actually, I mean, there is quite a nice little puzzle, I guess, that we could set people between now and when we do a full episode on this, Michael, right?

Go on, you do it.

You start off with your palm facing down and your hand flat.

And you need to get your thumb pointing in the air without rotating your wrist.