Re: Geiger (a challenge)

["Bernard G. Cleyet & Nancy Ann Seese" <georgeann@REDSHIFT.COM>]

I'm not certain what's going on here, but I prefer experiments to simulations first.  Stats are necessary to phys. not only for analysis of data (did we "really" verify the supposition?) and as
integral to an understanding of thermo and QM, and more?   In the case of nuclear phys -- decay theories include "randomness", therefore, LK's expt. IMAO is useful.

bc


John Denker wrote:

> At 06:16 PM 7/8/00 -0400, Ludwik Kowalski wrote:
>
> > MY POINT WAS THAT GEIGER COUNTS ARE HIGHLY RELIABLE SOURCES OF CLEAN DATA.
>
> We agree one objective is to have a reliable source of clean data.
>
> My point is that the rand() function is a highly reliable source of clean
> data.  Indeed, it is a more-reliable and cleaner source than any available
> Geiger counter.
>
> Perhaps Ludwik has some other as-yet-unstated objective(s) in mind.
>
> It was reported (09:03 AM 7/8/00 -0400) that the Geiger experiment
> > is tricky experiment to setup.
>
> In contrast, the numerical simulation is quite simple, and easily
> propagated from one classroom to another.
>    http://www.monmouth.com/~jsd/physics/iid-decay.xls  (185 k)
>    http://www.monmouth.com/~jsd/physics/iid-decay.zip  (35 k)
>
> > TRY TO COUNT REAL BUSSES AND ALL SORT OF UNUSUAL OUTCOMES
> > WILL BE OBSERVED, FROM TIME TO TIME.
>
> There is such a thing as a Gedankenexperiment.  Talking about idealized
> clockwork busses or IID busses is not a violation of any sacred
> commandments.  Indeed a Gedankenexperiment is often the best way to help
> students overcome a conceptual error.
>
> > THE QUESTION WAS ASKED WHY DO WE NEED EXPERIMENTS WHEN IDEALIZED
> > SIMULATIONS CAN BE PERFORMED WITH EXCEL? THIS IS PHILOSOPHY OF PHYSICS,
> > NOT PHYSICS.
>
> Actually I was responding to the remark (09:03 AM 7/8/00 -0400) that
> > The exponential distribution may be counter-intuitive.
>
> It remains my judgement that the exponential distribution is
> counter-intuitive if and only if the student has an incomplete grasp of
> elementary statistics.  It also remains my judgement that statistics is a
> branch of mathematics.  It is not a branch of physics, and it is certainly
> not a branch of philosophy.
>
> It remains my opinion that taking a mathematical misconception and dressing
> it up as an experimental physics puzzle does the student no good.  It's OK
> to motivate a mathematical question by explaining how the topic arises in
> the lab, but such motivation does not invalidate a mathematical analysis of
> a mathematical question.
>
> Experimental truths are not the only truths.  We don't need experiments to
> prove mathematical truths.
>
> Ludwik's question has a simple answer:
>    We need experiments to answer questions that cannot be answered
>    by mathematical analysis.
>
> Example:  Mathematics says that Kepler's 1-2-3 law applies to test
> particles moving in a 1/r potential.  Experiments are needed to see to what
> extent the real solar system can be approximated by a 1/r potential.
>
> There is nothing that can be obtained from the Geiger-counter experiment in
> question except for
>    a) an estimate of the average counting rate (which is not relevant to
> the conceptual question that was raised),
>    b) observations of nonidealities in the experimental setup (which also
> are not relevant to the conceptual question), and/or
>    c) a bunch of randomness and other things that can be obtained equally
> well from an excel simulation.
>
> Standard textbooks on pedagogy recommend using the "building block
> approach" which means that new concepts should be introduced in relatively
> simple contexts;  afterward the building blocks can be put together to
> treat more complex situations.
>
> It remains my recommendation to isolate the "counter-intuitive" exponential
> distribution and treat it as a simple mathematical question, separate from
> any "tricky" experimental setups.