Four university students entered a contest in which first prize
was a free years tuition. Their task was to figure out the
length of the Empire State building, using ONLY a barometer.
The first student who stepped forward was a Physics major.
He told the judges the problem was simple…you drop the
barometer off the top of the building and time how long it takes
to reach the bottom, then using the mathematical equation of a
falling body under gravity, calculate the height of the building.
The judges replied this was no good as you needed a watch, and
the only equipment available is the barometer.
The second student was an Engineering student who said her
solution was even simpler…tie a rope around the barometer and
lower it to the ground from the top of the building, then measure
the length of the rope and that is the height of the building.
The judges again replied this was no good as you needed a piece
of rope, and a measuring device in addition to the barometer.
The third student was an Envrionmental Studies major and knew
that the air pressure at the bottom of the building would be
different from the top. His proposal was that by measuring the
two air pressures and knowing something about the weather that
day, he could predict the height of the building.
The judges were somewhat skeptical of this idea and dismissed it
anyway, as the two air pressures would have to be calculated at
the same time, and that required the use of two barometers but
were only entitled to one.
Then the economics major stepped forward, looked at the other
three and said, “you fools…I’ve had one lecture in economics
and I can tell you the height of the building without even going
to the top. You see, on the side of the Empire State building is
a plaque, which shows amongst other things, the name of the
architect who built it. We go down to their office, ask somebody
there to look up the blueprints, which will tell us the height of
the building and we give them this nice barometer in exchange for
the information!”
