Re: [Phys-l] Movie Physics Gafs

["John Clement" <clement@hal-pc.org>]

This misconception is well documented by PER researchers, so one should not be surprised.  The Minds on Physics series very sensibly covers all of the long range non contact forces in one section.  So students are exposed to electrostatic, magnetic, and the general gravitational law all at once.  The distinction between how the forces are produces is clearly exposed.  So in testing for understanding questions are asked that reveal whether the confusion between electrical, magnetic, and gravitational forces is present.  There is one school educational website that talks about magnetic interactions as if it were electrical in nature and uses terms which I consider are designed to promote this misconception.

If you want to find out what students think just ask "What can magnets pick up?" and they will almost invariably say "metals".  MOP has them actually test a variety of materials such as aluminum, steel, copper, their own jewelry...  This has not been done in the lower grades, so they are severely misconcepted about how magnets work.

But when this sort of thing is put into commercial movies, you know that the directors don't know simple physics either.

John M. Clement
Houston, TX 

> Here is a video showing a compass made from a needle 
> magnetized with a silk cloth!
>
> http://www.youtube.com/watch?v=wIGbNJDYdnM&feature=player_detailpage
>
>
> From: Bob Sciamanda
> Sent: Monday, September 12, 2011 10:00 AM
> To: Forum for Physics Educators
> Subject: [Phys-l] Movie Physics Gafs
> I just watched “The Edge” (1997, Anthony Hopkins, Alec Baldwin).
> Lost in the wild, Hopkins (playing a very knowledgeable 
> outdoorsman) makes a compass by floating a needle on a leaf.
>
> But he “magnetizes” the needle by rubbing it with a piece of silk!