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Re: [Phys-l] bombastic put downs--was F causes a



John wrote
If somebody has evidence stronger than concluding force causes accelerations
because "the professor thinks that forces cause accelerations" I'd like to
see it.

Some of us were talking about getting our students to be better thinkers recently. As I teach my High School Physics class I most certainly do not want my students approaching F=ma or most any other equation or as I call them "guides to thinking" as a simple statement of equality. I want them to see a physical reality expressed by the equation. I want them to look at F=ma and say to themselves that it means that if I want a mass to accelerate I must apply a force to it. When they are doing that they are thinking about the meaning of the mathematics. That's good!

I am also careful to pound into their heads that the study of physics is about the study of models and that models are about ways of thinking about the physical interactions around them. ALL MODELS ARE WRONG. That does not mean that they are not useful. As you live your day to day life do you really think about gravity in terms of general relativity because Einstein's model is more powerful than Newton's? I doubt it. We all resort to Newton's ideas most of the time when we consider gravity. His model is more useful in day to day situations.

Now if John or others want to argue that thinking that F causes A is wrong I would have to say he has a point. It is wrong, just like all the other ideas (models) we have in physics, that doesn't mean however that it isn't useful. John's interpretation challenging the causation that I see in F=ma is also useful on some level. He is challenging my thinking, I like that.. However, if he wants to argue that my interpretation is wrong because I see causation where I shouldn't and that will lead my interpretation of F=ma astray in some situations, I have to say that his interpretation is wrong also because it will most certinly lead my students astray in may situations. Is that better than the professor says so?

P.S. I appreciate John's sharp ideas and his willingness to challenge my and others thinking. I also appreciate that fact that he recognizes that he sometimes makes mistakes or is indelicate when expressing his ideas and is quick to reconsider and apologize.