Sunday, April 19, 2009

cheeky physics

My favorite part of doing homework is coming across anecdotes that make me laugh.

There's a story about a physics student who, in answer to the exam question "Describe how the height of a building can be measured using a barometer," wrote "attach the barometer to a string and lower it from the top of the building. The length of the string needed to lower the barometer to the ground indicates the height of the building." The professor was looking for an answer that involved measuring barometric pressure on the ground and on top of the building, using principles learned in class. He therefore gave the student a zero for his answer.

The student protested the grade, so the case was given to another professor, who asked the student to provide an answer that would demonstrate his knowledge of physics. The student's answer was that the barometer could be dropped from the roof measuring how long it took to hit the ground. Using a formula involving the gravitational constant it would be possible to determine how far the barometer fell. The student was awarded full credit for that answer, and then, with a little prompting from the appeals professor, provided these additional answers:

  • Put the barometer in the sun and measure the length of its shadow and the length of the building's shadow. The height of the building could be determined using proportions.

  • Give the building superintendent the barometer in exchange for information about the height of the building.

Upon hearing these answers, the appeals professor was amazed, and asked the student whether he had known the right answer all along. The student replied that he did, but was tired of just repeating back information to get a good grade.

~ Lubart & Mouchiroud, 2003, as cited in Cognitive Psychology by Bruce Goldstein, 2008.

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