Ever wondered why our clocks have 60 seconds, 60 minutes, and 24 hours?

We use tens and hundreds for practically everything, so our clocks look a bit bizarre when you think about it!

Actually, an attempt was made to “sort this out” during the French Revolution. The day was chopped into 10 hours, with 100 minutes to an hour. But it wasn’t used for long…

Why? Because dividing an hour by a third or a sixth doesn’t work for 100, leaving you with messy, never-ending decimals. But it works perfectly fine for 60. It has a great mathematical advantage, splitting cleanly in 12 different ways, meaning you can chop your time into thirds, sixths, and twelfths without a single decimal in sight. It keeps our daily schedules beautifully simple.

So, next time you look at your watch, you can thank the ancient Sumerians for making everyday division of hours so easy. And while you’re at it, thank the Babylonians for our seven-day week, because that French calendar also tried to force everyone into a brutal nine-day workweek before getting a day off.

But wait… why a seven-day week? Seven is a prime number, meaning it can’t be divided cleanly at all?

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Published by Anders

Anders Hast received a PhD in Computerised Image processing at Uppsala university in 2004. In 2011 he spent one year at IIT, CNR, Pisa in Italy as an ERCIM fellow and after that he received a full time position as associate professor and in 2019 he became professor in image processing, both at Uppsala University. He has been affiliated with UPPMAX super computer centre where he worked as an application expert in Scientific Visualisation and later in the field of digital humanities together with the Centre for digital humanities in Uppsala. His recent research has focused on image processing and computer vision, for applications in microscopy, aerial photography, object recognition and especially hand written text recognition and face recognition.

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