[Phys-l] how to prove relativity

["Paul Lulai" <plulai@stanthony.k12.mn.us>]

Hello.
The note below was posted by a physics teacher on another list.  I
thought some folks here might have some answers.


Edited initial post
====================================
> The teacher and his wife (PhD in experimental psychology) have been
going back and forth for years about the 
> idea of special relativity, specifically time dilation.  She insists 
> that the ideas produced are ridiculous, can never be tested, etc.  
> When I point out the experimental evidence such as muons in the 
> atmosphere, difference in clocks moving at different speeds, and the 
> fact that GPS uses special relativity to help pinpoint location has 
> not helped to persuade her.  Does anyone know of any experiments that 
> could be easily interpreted by a non- physics person (She has never 
> taken a physics course and I have never taken a psychology course) to
help convince her?
> And finally are there any good definitions for time out there?
>
> Thanks

An Early Response
======================================
Did you mention taking the clock on a trip around the world on a plane (
Hafele- Keating experiment) ? She sounds inconvincible to me. I think
this is a chance to do an experiment on why people don't change their
minds even when confronted with unassailable evidence. That might
produce some useful and publishable results.


Response from Initial Poster (if that is an acceptable word here)
=================================================================
The usual hang up that we have is the definition of time.  If we talk
about time dilation she argues that how do you know that they way you
are measuring time is not changing and not necessarily time itself.  She
also argues that time is not a physical concept but is instead a human
construct to try and explain events.  According to her time can dilate
or contract because it is not real but merely a perception that humans
have created.  I have tried to define time in terms of light clocks,
atomic clocks, and entropy.  Does anyone have have a good definition for
time as it would exist in a physical quantity?  

The twin illustration of time dilation would be convincing evidence but
obviously it is not practical.  Has anyone every heard of trying to see
how accelerating a spacecraft to a high velocity would affect the
population growth of bacteria?  Bacteria growth on a medium is a fairly
predictable but if we see a significant reduction in growth (assuming we
can control other factors) that would be pretty convincing evidence that
a twin would not age as fast.

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I am curious about responses.  I have participated in this same
conversation with my wife.  I would have thought the muon lifetime would
work in place of the clock's for time dilation.  I've found with my wife
that the muon experiment is too strange for acceptance and the traveling
clock are different due to clock difference even after a discussion of
atomic clocks.  I sometimes think that people need to be ready to accept
concepts that are counter-intuitive.

Have a good day.
Paul.