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.

3 men in Saudi
An American, a Dutchman and a Frenchman are in Saudi Arabia, sharing a smuggled crate of booze.

Then Saudi police rush in and arrest them.

The mere possession of alcohol is a severe offense in Saudi Arabia.

For the terrible crime of actually being caught consuming the booze, they are all sentenced to death!

However, after many months and with the help of very good lawyers, they are able to successfully appeal their sentences down to life imprisonment.

By a stroke of luck, it was a Saudi national holiday the day their trial finished.

The extremely benevolent Sheikh decided they could be released after receiving just 20 lashes each with a whip.

As they were preparing for their punishment, the Sheikh announced: "It's my first wife's birthday today, and she has asked me to allow each of you one wish before your whipping."

The Dutchman was first in line, he thought for a while and then said: "Please tie a pillow to my back."

This was done, but the pillow only lasted 10 lashes before the whip went through. When the punishment was done he had to be carried away bleeding and crying with pain.

The Frenchman was next up. After watching the Dutchman in horror he said smugly: "Please fix two pillows to my back."

But even two pillows could only take 15 lashes before the whip went through again and the Frenchman was soon led away whimpering loudly.

The American was the last one up, but before he could say anything, the Sheikh turned to him and said: "You are from a most beautiful part of the world and your culture is one of the finest in the world. For this, you may have two wishes!"

"Thank you, your Most Royal and Merciful highness," the American replied. "In recognition of your kindness, my first wish is that you give me not 20, but 100 lashes."

"Not only are you an honorable, handsome and powerful man, you are also very brave." The Sheikh said with an admiring look on his face.

"If 100 lashes is what you desire, then so be it. And your second wish, what is it to be?" the Sheikh asked.

The American replied: "Tie the Frenchman to my back."

Submitted by Yisman
Edited by Curtis