Topic
Counting
3 articles
History of science
Why did ten days vanish in 1582?
People went to bed on the fourth of October and woke up on the fifteenth. Nothing happened to the Sun, and nobody lost any time. A rounding error had been accumulating for sixteen centuries, and somebody finally paid it off.
History of science
Why are there 60 minutes in an hour?
Everything else we count goes in tens. Time stubbornly does not, and the reason is a choice made five thousand years ago by people who had no easy way of writing a third.
Mathematics
Why do two people in your class probably share a birthday?
Thirty children, three hundred and sixty-five days, and no obvious way for two of them to collide. Yet in a class that size a shared birthday turns up about seven times in ten.