"The Height Of a Building"

This is an interesting article i came across some time ago. I thought it worthwhile to publish, since it enlightens us on various mundane ways ' to measure the height of a building ' -

There was a Physics student in the University of Copenhagen. In his degree exam a question was asked "
Describe the height of a skyscraper with a barometer?". One student replied - " tie a long piece of string
to the neck of the barometer , then lower the barometer from the roof of the skyscraper to the ground.
The length of the string plus the length of the length of the barometer will equal the height of
the barometer".
This highly original answer didn't strike a chord with the professor and the student
was failed. The student however, appealed on the grounds that the answer was indisputably correct. So
the university appointed an independent arbiter to decide the case. The arbiter declared that the
answer was indeed correct but it didn't display any knowledge of physics.
To resolve the problem it
was decided that the student was to be given 6 minutes within which he had to give a verbal answer
which showed at least a minimum familiarity with physics. For 5 minutes the student sat in silence,
deep in thought. The arbiter reminded him that the time was running out. The replied by saying that
he had several extremely relevant answers, but couldn't make up his mind. On being advised to hurry
up the student replied as follows -

"Firstly, you could take the barometer up to the roof of the skyscraper, drop it over the edge, and
measure the time it takes to reach the ground. The height of the building can be worked out by the
formula H = 0.5g * t2. But bad luck on the barometer."

"or if the sun is shining u could measure the height of the barometer, then set it one end and measure
the length of the shadow. Then u measure the lenght of the skyscrapers shadow, and thereafter
it is simple matter of proportional arithmetic to work out the height of the skyscraper".

"But if u wanted to be highly scientific about it, you could tie a short piece of string to the barometer
and swing it like a pendulum first st ground level and then on the roof. The height is worked out by
the difference in the gravitational restoring force T = 2pi ( sq root (1/g)).

" If u merely wanted to be boring and orthodox about it, u could measure the air pressure on the roof
of the skyscraper and on the ground, and convert the difference in millibars into feet to give the height
of the building".

" But since we are consistently being exorted to exercise independence of mind and apply scientific
methods, undoubtedly the best way would be to knock on the janitor's door and say to him ' If u
would like a nice new barometer , i will give one to u if u tell me the height of the building".

The student was Niels Bhor , the only Dane to win a Noble for Physics.