There are some wild exaggerations posted here so I will caution readers to take it "with a grain of salt", as the old saying goes.
- I'm thinking of moving to the PNW. It must be the air up there.
Some time ago I received a call from a colleague,
who asked if I would be the referee on the grading
of an examination question. He was about to give a
student a zero for his answer to a physics
question, while the student claimed he should
receive a perfect score and would if the system
were not set up against the student.
The instructor and the student agreed to an
impartial arbiter, and I was selected. I went to my
colleague's office and 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."
I pointed out that 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. A
high grade is supposed to certify competence in
physics, but the answer did not confirm this. I
suggested that the student have another try at
answering the question. I was not surprised that my
colleague agreed, but I was surprised when the
student did.
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 no. 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. In 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 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. He also said he was fed
up with his friends telling him he couldn't do
something he already did and he was thinking about
changing school's.
