The Student and The Barometer

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,if the sun is shining you could measure the height of the barometer, then set it on end and measure the length of its shadow. Then you measure the length of the skyscraper's shadow, and thereafter it is a simple matter of proportional arithmetic to work out the height of the skyscraper.

"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.

The name of the student was Niels Bohr, who later received the Nobel prize for Physics.

Sniglets - Words That Should Exist
Words That Should Exist But Don't==================================
 Snackmosphere - The 95% air inside bags of potato chips.  Ohnosecond - That very short moment in time during which you realize that you have pressed the wrong key and deleted hours, days, or weeks of work.  Eiffelites - Gangly people sitting in front of you at the movies who, no matter which direction you lean in, follow suit.  Meganegabar - The line you put on a check to prevent someone else from adding "and a million dollars."  Frust - The small line of debris that refuses to be swept onto the dust pan and keeps backing a person across the room until he finally decides to give up and sweep it under the rug.  Petrophobic - One who is embarrassed to undress in front of a household pet.  Snork - To spew what you're drinking or chewing in a fit of sudden laughter.  Cylences - long gaps in a phone conversation that occur because one person is also reading email, IMing or shopping online.  Accordianated - Being able to drive and re-fold a road map at the same time.  Exhaustipated - Being so tired that when you try to speak, nothing comes out right.  Testlosterone - The hormone that prevents men from stopping and asking for directions.  Refunable – Something you enjoyed so much you’d do it again.  Treeware - Documents made out of paper, as opposed to electronic documents.  Disconfect - To sterilize the piece of candy you dropped on the floor by blowing on it, somehow assuming this will remove all the germs.  Newtrons - The magnetized particles that amazingly hold Fig Newtons together.  Prairiedogged - The feeling of helplessness you get when co-workers in neighboring cubicles constantly pop their heads up to ask you stupid questions.  Aqualibrium - The point where the stream of drinking fountain water is at its perfect height, thus relieving the drinker from (A) having to suck the nozzle, or (B) squirting themself in the eye/ear.  Blamestorming - Sitting around in a group, discussing why a deadline was missed or a project failed and who was responsible.  Elecelleration - The mistaken notion that the more you press an elevator button the faster it will arrive.  Mallmanac - In a mall, the giant maze with blocks and numbers on it, otherwise known as the "Directory".  Hereoglyph - A little stick figure on a mallmanac that tells where you are.  Peppier - The waiter at a fancy restaurant whose sole purpose seems to be walking around asking diners if they want ground pepper.  Phonesia - The affliction of dialing a phone number and forgetting whom you were calling just as they answer.  Aeroma - The odor emanating from an exercise room after an aerobics class.  Dimp - A person who insults you in a cheap department store by asking, "Do you work here?"  Dessertification - The act of eating less than the entire meal, in order to "save room for dessert".  Kirby - A Small but repulsive piece of food prominently attached to a person's face or clothing.  Zen mail - an email message that arrives with no text in it.  Klong - The sudden overwhelming feeling of fear and panic when you feel that everything is going well and you have plenty of time and you suddenly remember there was someplace else VERY important that you are supposed to be RIGHT NOW, and it's nobody's fault but your own that you aren't there.  Snee - A sneeze that doesn't completely execute. You feel your nose tingling and you start inhaling, anticipating the forceful thrust of air and saliva that is expected, but it never materializes.