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-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
bounces@carnot.physics.buffalo.edu] On Behalf Of Philip Keller
Sent: Friday, May 15, 2009 9:18 AM
To: 'Forum for Physics Educators'
Subject: Re: [Phys-l] Relativity Question
I believe that the point is that the scientists on the train have NOT
been lied to. In their reference frame, their clocks ARE synchronized.
When you first introduce the setup to students, they don't realize that
when we say that both sets of scientists don't really have synchronized
clocks, we are reporting the facts from another reference frame, a
third reference frame no more valid or less valid than that of the
scientists on the two trains.
To take things further, you can consider a procedure that the
scientists could use to ensure that the clocks on their own train were
synchronized. Suppose that there is a star that is known to
occasionally emit a burst of light at a specific frequency. And
suppose you could design clocks that start running when exposed to that
frequency. You could preset your clocks but with each clock set
further ahead than the one before it. Then when the light from the
star reached the individual clock, it would start the clock. The
preset time differences would be to allow for the additional time it
takes for the light to reach that train car.
If both sets of train scientists performed this procedure, they could
each argue that their own clocks were in fact synchronized. And they
would each argue that the other train performed the procedure
incorrectly because that other train was in motion relative to the
light source -- but we weren't. So in the final analysis, it is
simultaneity that is relative and it leads to the other weird things
about clocks and lengths.
-----Original Message-----_______________________________________________
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
bounces@carnot.physics.buffalo.edu] On Behalf Of chuck britton
Sent: Friday, May 15, 2009 8:45 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] Relativity Question
Please elaborate a bit on this point.
Are you implying that the folks on the train can't 'really' have a
set of synchronized clocks?
or what is the swindle to which you refer?
On May 14, 2009, at May 14(Thu) 5:38 , John Denker wrote:
they involve some sort of swindle, such as lying to the
trainmen about their clocks.
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Forum for Physics Educators
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Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l