Why Do Clocks Run Clockwise?

When someone says to pass papers clockwise, you (hopefully) know exactly what they're talking about. Pass those papers to the left. It's engrained enough that it'd be easy to not realize there's a reason clocks run clockwise. If you asked your dad as a kid he might have said, "They move that way because they do. Go clean your room." That's not very helpful, but it's not entirely inaccurate.

The Today I Found Out YouTube channel has endeavored to explain this basic bit of knowledge we take for granted. And while the answer is kind of "just because," the channel contextualizes how we got to that point where the direction was just commonly accepted.

A big part of the reason clock hands move in the direction they do is because of the direction the Earth rotates, as well as the fact that a significant portion of civilization happened to develop in the Northern Hemisphere.

The video goes into detail, but the big nugget here is about sundials. If you jab a stick into the ground to make a sundial (with the stick serving as the sundial's gnomon) in a Northern Hemisphere country like Egypt, the shadow you'd tell time by moves in a clockwise direction. That's due to the rotation of the Earth. If you made the same sundial in South Africa, located in the Southern Hemisphere, the shadow would move counterclockwise.

As clock technology progressed and moved away from sundials, the hands of a clock continued to move in a clockwise direction. That's what everyone was used to. It made sense instantly because people were familiar with the sundial. So, if anyone every asks you why clocks run clockwise, feel free to say "just because they do." You'll be right, more or less.

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Dustin Nelson is a News Writer with Thrillist. He holds a Guinness World Record, but has never met the fingernail lady. He’s written for Sports Illustrated, Men’s Journal, The Rumpus, and other digital wonderlands. Follow him @dlukenelson.