The following concerns a question in a physics degree exam at the University
of Copenhagen:
"Describe how to determine the height of a skyscraper with a barometer."
One student replied:
"You 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 barometer will equal the height of 
the building."
This highly original answer so incensed the examiner that the student 
was failed immediately. The student appealed on the grounds that his 
answer was indisputably correct, and the university appointed an 
independent arbiter to decide the case. The arbiter judged that the 
answer was indeed correct, but did not display any noticeable knowledge
of physics. To resolve the problem it was decided to call the student 
in and allow him six minutes in which to provide a verbal answer which
showed at least a minimal familiarity with the basic principles of physics.
For five minutes the student sat in silence, forehead creased in though
t. The arbiter reminded him that time was running out, to which the student
replied that he had several extremely relevant answers but couldn't 
make up his mind which to use. 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 then be worked out from the formula 
H = 0.5g x t2. But bad luck on the barometer."

·  "Or if the sun is shining you could measure the height of the barometer,
then set it on end and measure the length of its shadow. Then you measure 
the length of the skyscraper's shadow, and thereafter it is a simple matter
of proportional arithmetic to work out the height of the skyscraper."

·  "But if you 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 at ground level and then on the roof of the skyscraper. The height
is worked out by the difference in the gravitational restoring force 
T = 2 pi sqrroot (l/g)."

·  "Or if the skyscraper has an outside emergency staircase, it would 
be easier to walk up it and mark off the height of the skyscraper in 
barometer lengths, then add them up."

·  "If you merely wanted to be boring and orthodox about it, of course,
you could use the barometer to 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 constantly being exhorted 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 you would like a nice
new barometer, I will give you this one if you tell me the height of this
skyscraper'." 

The student was Niels Bohr, the only Dane to win the Nobel prize for
Physics.

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