OK - a very tangential takeoff: Engineering prof assigns students this question: Explain how to determine the height of a very tall building using a barometer.

Obviously meant to use change in barometric pressure with altitude. But one student submitted the following:

There are several ways of doing this

1. On a sunny day, stand the barometer up in the sun, measure the length of its shadow relative to its height, then measure the length of the building’s shadow and calculate its height from that.

2. Go into the stairwell and climb the stairs to the top, marking off the length of the barometer on the wall, giving you the height of the building in “barometer units”.

3. Go onto the roof of the building and drop the barometer off the top and time how long it takes to hit the ground, then calculate the height using the well known formula of 32 ft./sec./sec.

4. Go into the office of the building superintendent and say “If you tell me how tall this building is, I will give you this nice barometer”.