Answer: Sundial Shadows

The movement of clocks is, for anyone old enough to have stared at them year in and year out, as natural as the travel of the sun from the eastern horizon to a late evening dip beneath the western horizon. And, as a matter of fact, it’s just as naturally intertwined.

Before mechanical clocks, there were sun dials. In the northern hemisphere, the shadow of the projection on a sundial, the time keeping point, sweeps from west to north to east just like the hands of a modern clock sweep around in a clockwise fashion. When people began constructing mechanical clocks with faces and hands in Europe they, naturally, arranged the clock face to mimic the movement of a sundial’s shadow.

When Europeans colonized the globe, they took their clocks and watches with them and, even in regions where the sundial shadow moved in reverse (such as South America), the right-to-left movement became the standard.