It seemed like nice story so I posted ...
Some time ago I was called by a colleague who asked me if I could assist in assessing a response to an application for examination. He intended to give a student a zero for his answer to a test of physical and the student claimed to deserve honors and that it would be if the system was rigged to the detriment of students. Both the student and the teacher agreed to accept the opinion of an impartial judge, and I was chosen for this. I went to the office of my colleague and I read the examination question: "To demonstrate how to determine the height of a building with the help of a barometer."
The student had answered: "Take the barometer to the top of the building, attach a long rope, lower it to the street and then bring it up, measuring the length of the rope. The length of the rope is equivalent to building height." I told him that the student had actually good his reasons, whereas he had really answered the question completely and correctly. On the other hand, if he had been given top marks, this would contribute to the positive assessment of his training in physics. A positive assessment should certify competence in physics, and the answer does not support this hypothesis. Therefore suggested that the student was given a second chance to answer the question. I was not surprised when my colleague agreed, but I was surprised when the student to agree.
so I gave the student six minutes to answer the question, with the early warning that the answer would have to demonstrate their knowledge di fisica. Alla fine dei primi cinque minuti, non aveva ancora scritto nulla. Gli chiesi se volesse ritirarsi, ma rispose di no. Aveva un sacco di risposte al problema, stava solo pensando a quale fosse la migliore. Gli chiesi scusa per averlo interrotto e lo pregai di continuare. Nel minuto successivo, scrisse fulmineamente una risposta che diceva: "Portate il barometro in cima all'edificio e sporgetevi in fuori oltre l'orlo del tetto. Lasciate cadere il barometro, cronometrandone la caduta e quindi, usando la formula x = 0.5*a*t^2, calcolare l'altezza dell'edificio." A quel punto, chiesi al mio collega se volesse arrendersi. Lui accettò, concedendo allo studente quasi il massimo dei voti.
Mentre me ne stavo andando dall'ufficio del colleague, I remembered that the student had said he had other responses to the problem, and asked what they were. "Well," said the student, "there are many ways to find out the height of a building using 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 then, using a simple proportion, determine the height of the building. " "Well," I said, "and there are other answers?"
"Sure," said the student. "There is a very simple measurement system that will appeal. In this method, you take the barometer and begin to climb the stairs. Climbing the stairs, you mark with a stroke length of the barometer on the wall. Then there are the notches, and this provides the building height in barometers. "" A very direct method. "" Of course. If you want a more sophisticated method, can tie the barometer to a piece of string, swing it like a pendulum, and determine the value of ga street level and on top of the building. The difference of the two values \u200b\u200bof g, we can calculate, in principle, the height of the building
"Similarly, one can take the barometer to the top of the building, attach a long rope, lower it almost to street level and then swing it like a pendulum. You can calculate the height of the building from the period of precession. "Finally," concluse "ci sono molti altri metodi per risolvere il problema. Probabilmente il migliore" disse "consiste nel portare il barometro nello scantinato, e bussare alla porta del custode. Quando il custode apre, gli si dice così: 'Signor Custode, ecco qui un bel barometro. Se lei mi dice l'altezza dell'edificio, io glielo regalo.' A questo punto, chiesi allo studente se davvero non conoscesse la risposta convenzionale alla domanda. Lui ammise di conoscerla, ma disse che si era francamente stufato di docenti universitari che cercavano di insegnargli come pensare.
Vi immaginate la faccia del nostro ormai non più giovane professore di Fisica Generale I se avessimo presentato noi una risposta del genere?
Sembra quasi di sentire il sonoro delle sue labbra : ) ... (rivolgersi a cappe per riprodurre l'esecuzione ^^)
(fonte www.apel-pediatri.it/RIDIAMO/ domanda %20di%20 fisica .ppt )
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