The following question appeared on a physics degree exam at the University of Copenhagen:
“Describe how to determine the height of a skyscraper with a barometer.”
One enterprising 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 verbally provide an 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 thought. 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 drop to the ground. The height of the building can then be worked out from the formula H = 1/2 gt squared (height equals half times gravity times time squared) but bad luck for 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. If you merely wanted to be boring and orthodox about it, of course, you could use the barometer to measure air pressure on the roof of the skyscraper, compare it with standard air pressure on the ground, and convert the difference in mili-bars into feet to give the height of the building.
But since we’re 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, ‘I will give you this nice new barometer, if you will tell me the height of this skyscraper.’ ”
The arbiter re-graded the student with an ‘A’.
“The difference between the reason of man and the instinct of the beast is this, that the beast does but know, but the man knows that he knows.”