This Sunday, we will all dutifully set our clocks back one hour for daylight saving time. But why is our day divided into 24 hours, each hour divided into 60 minutes, and each minute into 60 seconds?

If you’ve ever heard someone say a meeting is at 1630 and then felt your brain do a small cartwheel, you have met the 24-hour clock. In the United States, we mostly live by the 12-hour clock, with a.m ...