[PLUG] OT: Recommended Web Sites for Middle School Science Questions

Richard C. Steffens rsteff at comcast.net
Mon Aug 6 16:07:44 UTC 2007


Bill Barry wrote:

> Like all the laws of physics, it is not obviously true that the marble
> includes the speed of the car. For instance, it might depend on which
> direction the car is going, or how fast the car is going or who knows
> what.  For low car speeds it is has been experimentally confirmed  to
> be true that the marble does include the speed of the car  and does
> not depend on direction or speed.
> 
> While it is approximately true for marbles thrown in cars, it is not
> generally true. If the car is going near the speed of light, and the
> marble inside the car is thrown near the speed of light, then an
> observer fixed on the ground will not see the marble in the car going
> at twice the speed of light but will see a marble going under the
> speed of light. These corrections are embodied in the special theory
> of relativity.

Thanks for the reminder about near the speed of light. I forgot that the
two obey the same law of physics -- different paragraph, perhaps.

> I don't know about middle school explanations, but you might like this one
> http://press.princeton.edu/chapters/s8112.html
> 
> Not pertaining directly to marbles thrown in cars, but there are  some
> very nice demonstrations of modern physics here
> http://www.colorado.edu/physics/2000/index.pl
> that could be understood by a middle schooler

Thanks. Those are the kind of sites I was looking for.

-- 
Regards,

Dick Steffens




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