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 ...

Armies started using the 24-hour method of timekeeping as standard military time because, much like police, fire, and medical departments, every branch of the armed services is in continuous operation ...