Puzzles
Why the first elevator to arrive always seems to be going the 'wrong' way
A physicist with an office near the bottom of a building noticed the first elevator to stop at his floor was almost always heading down. A colleague near the top noticed the opposite: elevators reaching him were almost always heading up. Neither could figure out why, until they worked out the pattern together. What's going on?
Reveal the answer
Near the bottom of a building, most elevators are 'above' you and heading down to collect people before rising again, so a down-going car reaches you first more often — and the mirror image happens near the top. The effect, noticed by physicists Marvin Stern and George Gamow in the 1950s, comes purely from spending most of an elevator's time in the larger section of the building relative to where you're standing.