10. In an exam the following question was asked: ‘Describe how to determine the height of a skyscraper with a barometer.’ A student replied: ‘Tie a long piece of string to the barometer’s neck, then lower the barometer from the skyscraper’s roof to the floor. The length of the cord plus the length of the barometer corresponds to the height of the building.’

This highly original response outraged the examiner so that the student was fired immediately. He appealed to his fundamental rights, on the grounds that his answer was undeniably correct. The university appointed an independent arbitrator to decide the case. The referee judged that the answer was indeed correct but did not show any perceptible knowledge of physics …

To solve the problem, it was decided to re-enroll the student and allow him six minutes to give an oral answer that showed at least a minimal familiarity with the basic principles of physics. For five minutes, the student sat still, head forward, lost in thought. The referee reminded him that the time was running, to which the student responded that he had some extremely relevant answers but could not decide which one to use. When advised to hurry, he replied as follows:

‘First, you could take the barometer to the skyscraper’s roof, drop it over the edge, and measure the time it takes to reach the bottom.

The height of the building can be calculated using the formula

However, the barometer would be gone!

Or, if the sun is shining, you could measure the height of the barometer, raise it, and measure the length of its shadow. Then measure the length of the shadow of the skyscraper, then it’s easy to calculate the height of the skyscraper using proportional arithmetic.

But if you wanted to be highly scientific, you could tie a short piece of string to the barometer and let it swing like a pendulum, first on the ground and then on the roof of the skyscraper.

The height corresponds to the deviation of the gravitational recovery force

Or, if the skyscraper has an external emergency staircase, it would be easiest to climb up there, check the height of the skyscraper in barometer lengths, and add up.

But if you only want a boring and orthodox solution, then of course you can use the barometer to measure the air pressure on the roof of the skyscraper and on the ground and convert the difference in millibar to calculate the height of the building. But as we are constantly being asked to practice the independence of the mind and apply scientific methods, it would undoubtedly be much easier to knock on the janitor’s door and say, ‘If you want a nice new barometer, I’ll give this one to you, provided you tell me the height of this skyscraper.’

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