17 March 2003

POSTERS FOR OUR TIME # 1 11:20:00 AM    comment []     PHYSICS FOR BEGINNERS As a teacher I'm always delighted to find evidence of the mismatch between what goes on in the most vital & relevant of learning processes (education, we call it) & the curious, arcane & almost entirely unrelated activities of examination boards (whose province is schooling).  Shortly after I started training many years ago a sardonic aphorism went the rounds: 'Those can, do; those who can't, teach; those who can't teach, teach teachers'. I came across the following a short while ago... The story concerns a question in a physics degree exam at the University of Copenhagen: 'Describe how to determine the height of a skyscraper with a barometer'.  One student replied: 'You tie a long piece of string to the neck of the barometer and then lower the barometer from the roof of the skyscraper to the ground. The length of the string plus the length of the barometer will equal the height of the building'.  This highly original answer so incensed the examiner that the student was failed immediately. The student appealed on the grounds that his answer was indisputably correct, and the university appointed an independent arbiter to decide the case. The arbiter judged that the answer was indeed correct, but did not display any noticeable knowledge of physics. To resolve the problem it was decided to call the student in and allow him six minutes in which to provide a verbal answer which showed at least a minimal familiarity with the basic principles of physics. For five minutes the student sat in silence, forehead creased in thought.  The arbiter reminded him that time was running out, to which the student replied that he had several extremely relevant answers, but couldn't make up his mind which to use. On being advised to hurry up the student replied as follows: "Firstly, you could take the barometer up to the roof of the skyscraper, drop it over the edge, and measure the time it takes to reach the ground. The height of the building can then be worked out from the formula H = 0.5g x t squared. But bad luck on the barometer.  "Or 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. "But if you wanted to be highly scientific about it, you could tie a short piece of string to the barometer and swing it like a pendulum, first at ground level and then on the roof of the skyscraper. The height is worked out by the difference in the gravitational restoring force T = 2 pi sq. root (l / g).  "Or if the skyscraper has an outside emergency staircase, it would be easier to walk up it and mark off the height of the skyscraper in barometer lengths, then add them up.  If you merely wanted to be boring and orthodox about it, of course, you could use the barometer to measure the air pressure on the roof of the skyscraper and on the ground, and convert the difference in millibars into feet to give the height of the building.  "But since we are constantly being exhorted to exercise independence of mind and apply scientific methods, undoubtedly the best way would be to knock on the janitor's door and say to him, 'If you would like a nice new barometer, I will give you this one if you tell me the height of this skyscraper'". The student was Niels Bohr, the only Dane to win the Nobel Prize for Physics.   10:46:45 AM    comment [] MEANWHILE, BACK ON THE HOME FRONT From the ridiculous to the sublime... The following was put together by an anonymous mother in Austin, Texas. As a father again after 28 years, I read it & wept. Things I've learned from my children (honest & no kidding) A king-size waterbed holds enough water to fill a 2,000 sq. ft. house 4 inches deep. If you spray hairspray on dust bunnies & run over them with roller blades, they can ignite. A 3-year-old's voice is louder than 200 adults in a crowded restaurant. If you hook a dogleash over a ceiling fan, the motor is not strong enough to rotate a 42-pound boy wearing Batman underwear & a Superman cape. It is strong enough, however, if tied to a paint can, to spread paint on all four walls of a 20x20 ft. room. You should not throw baseballs up when a ceiling fan is on. When using a ceiling fan as a bat, you have to throw the ball up a few times before you get a hit. A ceiling fan can hit a baseball a long way. The glass in windows (even double-pane) doesn't stop a baseball hit by a ceiling fan. When you hear the toilet flush and the words "uh-oh", it's already too late. Brake fluid mixed with Clorox makes smoke, and lots of it. A 6-year old can start a fire with a flint rock even though a 36-year old man says they can only do it in the movies. Certain Leggos will pass through the digestive tract of a 4-year old. Playdough & microwave should not be used in the same sentence. Superglue is forever. No matter how much Jell-O you put in a swimming pool you still can't walk on water. Pool filters do not like Jell-O. VCRs do not eject peanut butter & jam sandwiches even though TV commercials show that they do. Garbage bags do not make good parachutes. Marbles in gas tanks make lots of noise when you're driving. Always look in the oven before you turn it on. Plastic toys do not like ovens. The fire department in Austin, Texas, has a 5-minute response time. The spin cycle on the washing machine does not make earthworms dizzy. It will, however, make cats dizzy. Cats throw up twice their body weight when dizzy.   12:29:42 AM    comment []

© Copyright 2003 Dick Jones. Last update: 31/03/2003; 22:46:09.