Keeping Time

Some people are really good at tapping their foot to keep time. Other folks can get within a second or two if you ask them to estimate when they think a minute has gone by.

Even the very best of us, though, makes mistakes. Seconds add up to minutes, and these missing minutes made a difference even in the ancient world.

The Sun provides a simple, reliable way to track the time. For millennia, humans could simply look at the Sun’s position in the sky to guess what time it was in the day. This was important at first because daylight could determine survival, but it became increasingly important to be accurate as our population grew.

Someone had the idea of observing the shadow the Sun cast instead of tracking its position in the sky. Eventually, someone else had the idea to put marks on the ground around a stick. Discrete markers of the day were now possible.

This led to the creation of the sundial, a standalone device for just this purpose. 3500 years ago, they were making these in Ancie…