62 22 August 2007 03:40AM

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Comment author: 28 May 2012 07:56:06PM *  8 points [-]

(Thread necromancy courtesy of TeMPOraL's comment.)

inclined plane

Here's Feynman criticizing the Brazilian educational system (in the late 1940s and early 1950s), but I get the impression from his writing that he thought this was a widespread problem that was particularly bad in Brazil. (See for instance the stuff about American textbooks later "Surely You're Joking".)

Then I held up the elementary physics textbook they were using. "There are no experimental results mentioned anywhere in this book, except in one place where there is a ball, rolling down an inclined plane, in which it says how far the ball got after one second, two seconds, three seconds, and so on. The numbers have 'errors' in them -- that is, if you look at them, you think you're looking at experimental results, because the numbers are a little above, or a little below, the theoretical values. The book even talks about having to correct the experimental errors -- very fine. The trouble is, when you calculate the value of the acceleration constant from these values, you get the right answer. But a ball rolling down an inclined plane, if it is actually done, has an inertia to get it to turn, and will, if you do the experiment, produce five-sevenths of the right answer, because of the extra energy needed to go into the rotation of the ball. Therefore this single example of experimental 'results' is obtained from a fake experiment. Nobody had rolled such a ball, or they would never have gotten those results!

-- "Surely You're Joking, Mr. Feynman!", Richard Feynman (p. 217)

Comment author: [deleted] 10 August 2013 12:46:40PM 0 points [-]

Not to mention all the 20th-century textbooks mentioning the tongue map thing...

Comment author: 12 May 2015 12:48:44AM 0 points [-]

Page 212-213 is even more on point.

After a lot of investigation, I finally figured out that the students had memorized everything, but they didn't know what anything meant. ... So you see, they could pass the examinations, and "learn" all this stuff, and not know anything at all, except what they had memorized.

He gives several examples relating to the physics of light and torque. The students give great definitions but have no idea how to apply the terms to any real objects, even when the objects are pointed out to them.