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.

Funny Words of Wisdom
Funny Words of Wisdom =========================  To spot the expert, pick the one who predicts the job will take the longest and cost the most.  The other line always moves faster.  Never play leapfrog with a unicorn.  If you're feeling good, don't worry, you'll get over it.  If there is a possibility of several things going wrong, the one that will cause the most damage will be the one to go wrong.  A meeting is an event at which the minutes are kept and the hours are lost.  Friends come and go, but enemies accumulate.  If you try to please everybody, nobody will like it.  A short cut is the longest distance between two points.  The chance of a piece of bread falling with the buttered side down is directly proportional to the cost of the carpet.  Anything you try to fix will take longer and cost more than you thought.  Murphy Was an Optimist........  When a broken appliance is demonstrated for the repairman, it will work perfectly.  Everyone has a scheme for getting rich that will not work.  When in doubt, mumble. When in trouble, delegate.  Nature always sides with the hidden flaw.  If everything seems to be going well, you obviously don't know what the heck is going on.  You will always find something in the last place you look.  No matter how long or hard you shop for an item, after you've bought it, it will be on sale somewhere cheaper.  Leakproof seals - will.  There is always one more bug.  In order to get a loan, you must first prove you don't need it.  If you fool around with a thing for very long, you will screw it up.  If if jams - force it. If it breaks, it needed replacing anyway.  A pipe gives a wise man time to think and a fool something to stick in his mouth.  Build a system that even a fool can use, and only a fool will use it.  You will remember that you forgot to take out the trash when the garbage truck is two doors away.  Anything good in life is either illegal, immoral or fattening.  Tell a man there are 300 billion stars in the universe and he'll believe you. Tell him a bench has wet paint on it, and he'll have to touch it to be sure.  The first myth of management is that it exists.  New systems generate new problems.  Nothing motivates a man more than to see his boss putting in an honest day's work.  The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman.  After all is said and done, a heck of a lot more is said than done.  A bird in hand is safer than one overhead.  The light at the end of the tunnel is the headlamp of an oncoming train.  A Smith & Wesson beats four aces.  If more than one person is responsible for a miscalculation, no one will be at fault.  Never argue with a fool, people might not know the difference.  Anything that can go wrong, will go wrong.  You can never tell which way the train went by looking at the track.  Whenever a system becomes completely defined, some damn fool discovers something which either abolishes the system or expands it beyond recognition.  A complex system that works is invariably found to have evolved from a simple system that works.  Computers are unreliable, but humans are even more unreliable. Any system which depends on human reliability is unreliable.  Under the most rigorously controlled conditions of pressure, temperature, volume, humidity, and other variables the organism will do as it damn well pleases.  The only perfect science is hind-sight.  When all else fails, read the instructions.  Any simple theory will be worded in the most complicated way.  The degree of technical competence is inversely proportional to the level of management.  Logic is a systematic method of coming to the wrong conclusion with confidence.  Technology is dominated by those who manage what they do not understand.  The opulence of the front office decor varies inversely with the fundamental solvency of the firm.  Nothing ever gets built on schedule.  A failure will not appear till a unit has passed final inspection.