Sir Ernest Rutherford, President of the Royal
> Academy, and recipient of
> the Nobel Prize in Physics, related the following
> story:
>
> Some time ago I received a call from a colleague. He
> was about to give a
> student a zero for his answer to a physics question,
> while the student
> claimed a perfect score. The instructor and the
> student agreed to an
> impartial arbiter, and I was selected. I read the
> examination question:
>
> "Show how it is possible to determine the height of
> a tall building with
> the aid of a barometer."
>
> The student had answered: "Take the barometer to the
> top of the
> building, attach a long rope to it, lower it to the
> street, and then
> bring it up, measuring the length of the rope. The
> length of the rope is
> the height of the building."
>
> The student really had a strong case for full credit
> since he had really
> answered the question completely and correctly! On
> the other hand, if
> full credit were given, it could well contribute to
> a high grade in his
> physics course and certify competence in physics,
> but the answer did not
> confirm this.
>
> I suggested that the student have another try. I
> gave the student six
> minutes to answer the question with the warning that
> the answer should
> show some knowledge of physics. At the end of five
> minutes, he hadn't
> written anything. I asked if he wished to give up,
> but he said he had
> many answers to this problem; he was just thinking
> of the best one. I
> excused myself for interrupting him and asked him to
> please go on. In
> the next minute, he dashed off his answer, which
> read, "Take the
> barometer to the top of the building and lean over
> the edge of the roof.
> Drop the barometer, timing its fall with a
> stopwatch. Then, using the
> formula x=0.5*a*t^2, calculate the height of the
> building."
>
> At this point, I asked my colleague if he would give
> up. He conceded,
> and gave the student almost full credit. While
> leaving my colleague's
> office, I recalled that the student had said that he
> had other answers
> to the problem, so I asked him what they were.
>
> "Well," said the student, "there are many ways of
> getting the height of
> a tall building with the aid of a barometer. For
> example, you could take
> the barometer out on a sunny day and measure the
> height of the
> barometer, the length of its shadow, and the length
> of the shadow of the
> building, and by the use of simple proportion,
> determine the height of
> the building."
>
> "Fine," I said, "and others?" "Yes," said the
> student, "there is a
> very basic measurement method you will like. In this
> method, you take
> the barometer and begin to walk up the stairs. As
> you climb the stairs,
> you mark off the length of the barometer along the
> wall. You then count
> the number of marks, and this will give you the
> height of the building
> in barometer units. A very direct method." "Of
> course.
>
> If you want a more sophisticated method, you can tie
> the barometer to
> the end of a string, swing it as a pendulum, and
> determine the value of
> g [gravity] at the street level and at the top of
> the building. From the
> difference between the two values of g, the height
> of the building, in
> principle, can be calculated."
>
> "On this same tack, you could take the barometer to
> the top of the
> building, attach a long rope to it, lower it to just
> above the street,
> and then swing it as a pendulum. You could then
> calculate the height of
> the building by the period of the precession".
>
> "Finally," he concluded, "there are many other ways
> of solving the
> problem. Probably the best," he said, "is to take
> the barometer to the
> basement and knock on the superintendent's door.
> When the superintendent
> answers, you Speak to him as follows: 'Mr.
> Superintendent, here is a
> fine barometer. If you will tell me the height of
> the building, I will
> give you this barometer.'"
>
> At this point, I asked the student if he really did
> not know the
> conventional answer to this question. He admitted
> that he did, but said
> that he was fed up with high school and college
> instructors trying to
> teach him how to think.
>
> Who was that student?
>
> The student was Niel Bohr (1885-1962), Danish
> Physicist, Nobel-Prize
> winner in 1922, best known for proposing the first
> 'model' of the atom
> with protons & neutrons, and various energy states
> of the surrounding
> electrons--the familiar icon of the small nucleus
> circled by three
> elliptical orbits ... but more significantly, an
> innovator in Quantum
> Theory.
>
> Can we give our children the freedom to think?

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ani

I love re-reading this. What a powerful message!