Why are manhole covers round? Became a famous question after Microsoft used it in job interviews.
Random and
seemingly strange job interview questions are the subject of countless articles
during hiring season. Most of these are not about reaching a right answer, but
rather to see how someone's brain works in reaching towards an answer.
Microsoft used
questions like this to 'distinguish between people who are smart and get things
done, people who are smart but don't get things done, and people who get things
done but are not smart.'
Some of the reasons are these, a round manhole
cover cannot fall through its circular opening, whereas a square manhole cover
could fall in if it were inserted diagonally in the hole. Circular covers
don’t need to be rotated or precisely aligned when placing them on the opening. A round manhole
cover is easily moved and rolled. Human beings have
a roughly circular cross-section. Round tubes are
the strongest shape against the compression of the earth around them, so the
cover of the tube would naturally be round as well. It’s easier to dig
a circular hole. Round castings are
much easier to manufacture using a lathe.
