Eddie Wu

They're each vibrating one another and passing that heat energy along the way until it is evenly spread throughout the environment, which is why, of course, if you come to that cup of coffee after an hour,

it will be exactly the same temperature as the surrounding environment, which is probably not very pleasant to drink.

If you just have 23 people in a room, there is a 50% chance that two of those people are going to share the same birthday, which sounds ridiculous, but it actually is true.

And we can prove it mathematically in the same way that we were doing that compound interest explanation before.

Every additional person that you add has more possible connections with every other person in the group.

And to make sure that no one has the same birthday, actually, there are fewer and fewer days that are possible.

And when you go ahead and you do the probability calculation, it ends up, I think it's 50.06% when there is 23 people in the room.

And that seems extremely surprising, but the mathematics bears it out.

And I think that's one of the things that's most powerful about mathematics.

We have this intuition for how the natural world works, but sometimes we're surprised by things and mathematics can help us to actually use clear logic and deduction to see what's really true.

Yes.

So again, I know this is very counterintuitive, but let's think about it from the opposite point of view.

This is something that mathematicians call the complement.

So the probability that we don't share the same birthday is 364 out of 365, which again, seems like an extremely high chance.

It's more than 99%, right?

So of course it's,

unlikely that we would share the same birthday.

There's more than a 99% chance we've got different ones.

But when we add the next person in, we're not multiplying by 364 divided by 365.

There are a few options.