What is 360 degrees?

Welcome to Matt Is Not Boring by Kidopoly.com. I'm Mira. And I'm Finn. If you haven't already, tap follow wherever you're listening so you never miss an episode.

Hey Mira, have you ever watched someone on a skateboard go flying off a ramp and do a full crazy spin in the air before landing?

I absolutely have. They jump up, spin all the way around in a complete circle, and manage to land facing the exact same way they started. It looks like so much fun. Do you know what they call that trick?

Yeah, everyone calls it a 360. But wait, I have always wondered about that name. Why on earth is it a 360? What are they actually counting when they spin?

That is the perfect question, Finn. Because 360 is a pretty huge number. If you just spin around in a circle exactly one time, why would anyone look at that and say you did 360 of anything?

Exactly. I mean, I only spun once. If I tried to spin 360 times, I would be so dizzy I'd probably fall over into a bush. It just doesn't make any sense to use such a giant number for one little turn.

Well, today we are going to explore exactly what that number means. It is a mathematical secret that hides everywhere. It hides in the sharp corners of your favourite books, on the glowing compass in a smartphone, and in the very way giant ships steer across the ocean.

Oh, I absolutely love a secret code. But seriously, where does a number like that even come from?

To understand what a 360 actually is, we need to talk about the real mathematical name for these turns. When you spin around in a circle, you are turning through something called degrees.

Wait, degrees? Like how hot or cold it is outside in the summer.

It is spelled exactly the same way, but it means something completely different in geometry. A degree is a tiny, tiny, extremely small part of a turn. Imagine taking a full, perfectly round circle and carefully slicing it into 360 perfectly equal tiny slivers. The angle of each of those little slivers is exactly one degree.

Wow, so a full turn is exactly 360 degrees. That is why a skateboarder calls a fun full spin a 360. They are spinning all the way through every single one of those little slices in the air.

You got it! Turn all the way round and you have turned exactly 360 degrees. But the really amazing part is who actually came up with that number in the first place.

Did someone just invent it recently to make skateboarding sound much cooler?

Not quite. That number comes from a group of brilliant astronomers in ancient Babylon. Babylon? That sounds incredibly ancient. Where and when was that? Very ancient. This happened between about 500 and 300 BCE, more than 2,000 years ago. The Babylonians were incredible at studying the night sky. They watched the stars, the moon, and the sun, and they decided to split the giant circle of the sky into 360 equal parts.

So they just stood outside, looked up at the whole entire sky, and chopped it into 360 slices. But why 360? Why not something simple like a hundred or a thousand?

That is one of the biggest mysteries in mathematics, Finn. Nobody knows for certain why they chose 360. The historians do not have a lost diary from a Babylonian astronomer explaining the exact reason. It is a genuine open question.

Wait, really? We have been using this number for thousands of years, all the time, and we don't even know for a fact why they picked it in the first place.

We don't know for an absolute fact, but historians and mathematicians have a couple of really likely ideas that make a whole lot of sense. The first idea is all about how the sky moves over time.

How the sky moves. Like the way the stars move around at night. Exactly.

If you watch the night sky carefully, the stars shift a tiny step each night. They keep stepping, night after night, moving along a giant circle. And they come back around to where they started after about a year.

Oh I know this. And a year is about 365 days.

Yes, a year is close to 365 days. Now, the Babylonians were incredibly smart, and they knew the year was not exactly 360 days. But 360 is really, really close to a year.

That is so beautiful. It is like one degree is almost exactly one day of the year. One tiny step for the stars every single night until they make a full, complete circle.

Exactly. Dividing the circle of the sky into 360 degrees meant the stars moved roughly one degree each night. It gave those ancient astronomers a perfect way to map the heavens.

Okay, but hold on. If the year is actually closer to 365, why didn't they just divide the sky into 365 degrees instead? That would be totally exact.

Well, that brings us to the second likely reason. And it is something you will definitely appreciate. Imagine trying to share a pizza that has exactly 365 slices with your friends.

And 365 is a terrible number to share out evenly. You cannot even cut it in half without getting a weird fraction.

Exactly. But 360 can be shared out evenly in a huge number of ways. You can divide it perfectly by two, three, four, five, six, eight, nine, ten, twelve, fifteen, and it just keeps going.

Whoa, that makes it super easy to split up a circle into half turns, or third turns, or even tiny slices without any messy leftovers.

And the Babylonians absolutely loved numbers that could be shared easily, because they already counted in sixties. We talked about their special counting system in another episode. Oh yeah, base sixty. Right, and six groups of sixty is exactly 360. So the number perfectly married their everyday mathematics with the starry sky above them.

That is just brilliant. They took a number that was almost exactly a year, and also a number that was incredibly easy to divide, and they used it to measure the whole universe.

They really did. And because 360 is so perfectly easy to divide, let's think about a quarter turn. Imagine standing facing forward and spinning only a quarter of the way around.

Oh, I can picture that. A quarter of those 360 tiny angles would mean turning exactly 90 of them.

Exactly! A quarter turn is exactly 90 degrees.

Wait, 90 degrees? That sounds super familiar to me. I feel like I hear that number all the time. It is.

A quarter turn makes what we call a right angle. The corner of a book is exactly 90 degrees. The corner of your bedroom, the edge of a piece of paper, the corner of a table. 90 degrees is everywhere you look.

So every single time I look at the sharp corner of a book, I am literally looking at a quarter of the Babylonian sky.

You absolutely are. And this ancient idea did not just stay stuck in Babylon. Today, degrees steer giant cargo ships across the ocean. They guide airplanes flying high through the clouds. And they run the digital compass right on a phone.

That is wild! When a pilot turns an airplane to a new direction, they are using the exact same 360 degrees the ancient astronomers used to track the stars.

It is one huge continuous story. So the next time you see a skateboarder doing a fun 360 spin in the park, or you just notice the corner of a book, you will know you are looking at a 2,000-year-old piece of the night sky. Alright, Finn, it is quiz time! Let's see what you remember.

Okay, I am totally ready. I've got my ancient astronomer hat firmly on.

First question. What is the mathematical name for the 360 tiny angles of a full turn? Next one. Which ancient group of people first divided the sky into 360 parts? Question 3. Between which years BCE did this happen? Here's number four. What is a quarter turn or the corner of a book called in degrees?

Last question. Besides skateboards, what is one modern thing that degrees help steer or guide? Great job! Let's go through the answers and see how you did. The first answer is they are called degrees. For question two, it was the brilliant astronomers in ancient Babylon. Number three, the answer is this happened between about 500 to 300 BCE.

Question 4. A quarter turn is exactly 90 degrees. And the final answer is degrees steer ships, airplanes, and the compass on a phone.

I am genuinely never going to look at the corner of a book the exact same way again. It is literally a piece of ancient history hiding right there on my bookshelf.

That is the very best part of maths, Finn. It just turns completely ordinary things into something extraordinary without changing them at all.

And knowing that nobody knows for absolute sure why they chose 360 just makes it feel like a grand, beautiful mystery we get to share together.

If you love learning about the ancient Babylonian sky with us today, please leave us a five-star review. Just scroll down and tap the stars.

Oh, and we have sister shows too. History, science and philosophies not boring. Go give those a listen and a follow as well.

Want your name on the show? Send us an email at hello at kidopoly.com.

See you next time on Maths Is Not Boring. Bye everyone.

What is 360 degrees?

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