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>From: Barak Rosenshine <[log in to unmask]>
>Subject: Not a true story
>A not true 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 IS IT 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 the rope
>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 to 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 had not 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 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 tact, 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.
>



*********************************
Norman A. Stahl, Acting Chair
Department of Literacy,
Intercultural and Language Education
GH 223c
Northern Illinois University
DeKalb, IL  60115

Telephone:
(815) 753-9032 {office}
(815) 753-8563 (FAX)

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