Re: relativity labs

[Bernard Cleyet <georgeann@REDSHIFT.COM>]

I've never done this, but if easily done, I think is a more direct and
intuitive SR demo.

with a kinescope note that the deflection due to the deflection plates
field is reduced faster than predicted with increasing anode voltage.
i.e. the mass of the electrons has increased.  One can easily calc. if
it should be noticeable (measurable) upon increasing the voltage from
say 100 v. to a kilo volt.  May be not as the rest mass is ~ 1/2 mev?
Maybe a typical tube 5BP1 can tolerate 10 kV.  10^4 / 0.55 x 10^6 --- 2
% ?   color tubes use ~ 20 kV.  but then it's mag.. deflection and the
intuitive nature is lost   I think telling students mag. and E fields
are the same (because of SR) doesn't cut it.

bc



Ben Crowell wrote:

> Does anyone know of any good relativity labs for an
> introductory course? Jackson refers to a lab with a
> NaI detector to verify the relativistic energy-
> momentum relationship, but I haven't yet made the
> pilgrimage to the closest school that has the
> journal it's described in. Other possibilities
> that occur to me include observing pair production
> by cosmic rays in a cloud chamber, or doing something
> with GPS (GPS requires general relativity
> corrections). Ideally I'd like something affordable
> that could be done hands-on by six lab groups,
> each with their own equipment, but I realize that's
> asking a lot.
>
> On a related note, has anyone bought and maintained
> a NaI detector for undergraduate use? Can they
> be gotten cheap via surplus? Is there
> cheap ADC/histogramming software and
> hardware for PC-compatibles?