BrainStuff Classics: Why Are There 60 Minutes In An Hour Instead of 100?

Lots of human mathematics are based around multiples of the number 10 -- so why do we measure time in multiples of 12? Learn more in this classic episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of I Heart Radio.
Hey brain Stuff. I'm Lauren Wogelbaum, and today's episode is
a classic from our previous host, Christian Sagar. And this
is one that still messes with me all the time.
No time pun intended. Well, why are there sixty minutes
in an hour instead of a hundred? Hey, brain stuff,

(00:25):
it's Christian Sagar in Today's question is why do we
measure time the way we do? At the first glance,
it seems like it's a sensible thing until we start
delving into it. So let's start with a day. What
is a day. A day is just the amount of
time that it takes our globe to make a full
rotation on its axis. Simple, right. But then we divide

(00:48):
a day into twenty four parts for some reason, and
then of those twenty four hours, we measure those in
sixty minute increments for some reason. And then we get
down to a in it we measure that in terms
of seconds, again a collection of sixty for some reason.
But when we get to seconds, we measure those in

(01:09):
the most popular numerical system today, the decimal system, So
we talk in terms of a hundredth of a second
or a millionth of a second. But why how do
we even start measuring days and dividing them this way. Well,
the Babylonians were measuring time in what's called a sexy
gescimal system as opposed to a decimal system. They were

(01:31):
based on sixty instead of base ten. So earlier we
said that the decimal system is the most popular, and
it makes sense, right because the vast majority of human
beings have ten fingers. It's very easy for the human
species to count to ten. So why would you use
something that relies on sixty or why would you use

(01:52):
something that relies on twelve. Well, when we look at
the Babylonian system, it actually makes some sense. There is
a method to this ancient madness. And here's why. If
we use the base ten idea ten to one hundred,
the notation that we would have to make to measure
a specific time of day would become ridiculous very quickly,

(02:13):
and complicated as well. The thing is that sixty has
some advantages because sixty, if you just break it down,
is essentially five times twelve. Then it has both the
advantages of a ten and twelve as a system. So
that is why it makes sense for us to use
sixty seconds in sixty minutes. But the big explanation that

(02:36):
no one's figured out yet is how this spread around
the world. Did it happen because it was an accident
of history? Did it happen because it was really the
most efficient way that human beings have figured out how
to measure time. And one last thing, we're all familiar
with AM and PM right. AM stands for anti meridium
and PM stands for post meridium. These are terms that

(02:59):
came about r the Roman era, when they used to
divide the entire day into two things, just AM and PM.
This was so important, in fact, that they used to
have these people whose only job was to wait until
the sun crossed over so they could run to the
forum and say, hey, everybody, Okay, it is noon. It

(03:20):
is officially p M. And the reason why is because
lawyers were required to show up by noon. Today's episode
was written by Ben Bollen and produced by Tyler Clang.
For more on this and lots of other topics, visit
how Stuff works dot com. Brain Stuff is production of
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(03:42):
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