The following story has appeared in print many times over the years, and has become a living legend in science education.
The final exam in a certain physics class contained this problem: "Show how it is possible to determine the height of a tall building with a barometer."
One student answered, "tie a string to the barometer, let the barometer down from the roof of the building, and measure how much string you let out before the barometer touches ground." The professor was unsatisfied with this.
"All right," the student replied. "Here are some other possibilities. Drop the barometer from the roof, time its fall with a stopwatch; calculate the height of the building from the time of fall."
"Or, climb the stairs of the building, using the barometer case as a measuring unit. Make evenly spaced marks along the wall; count the marks to find the height of the building in barometer units."
"Best of all, offer to give the barometer to the superintendent of the building, if he'll tell you the height of the building."
The student was asked whether he knew the conventional answer.
"Of course," the student replied. "Use the barometer to measure the atmospheric pressure at the ground and at the top of the building. Atmospheric pressure decreases with height. The pressure difference between top and bottom allows you to figure the height of the building."
"Why didn't you say so in the first place?" the professor asked.
The student explained that he was fed up with memorizing conventional answers and decided to protest by giving every workable answer he could think of, except the one he knew the professor wanted.
Sources And Further Reading:
- Anecdote by Alexander Calandra, reprinted in R. L. Weber, Ed., More Random Walks in Science (1982) and Saturday Review (Dec. 21, 1968, p. 60) from a book by Calandra. (link takes you to
- F. Hechinger, "Thinking Critically," New York Times (education page), Feb. 24, 1987.
- Reading for Philosophical Inquiry: A Brief Introduction to Philosophical ThinkingÂ ver. 0.21; An Open Source Reader. Chapter 3. The Nature of Philosophical Inquiry.