Re: work function +- contact electrification

[Joseph Bellina <jbellina@SAINTMARYS.EDU>]

I agree that moving to a discussion of work-function might be a useful
educational activity since there is more data, and the topic appears to
be simpler.  On the other hand, it does not necessarily give more
insight in to the original question about the triboelectric series since
most of the items in the list are not conductors, whereas the notion of
work function is most meaningful for conductors.  Further an appeal to
work function is apparently not sufficient to explain triboelectric
effects.
As I mentioned before, I suspect the tack taken by Sherwood and Chabay
in terms of ionic transfer by polymer fragmentation may be a more
fruitful model for explaining the series.

cheers,

joe

On Thu, 20 Apr 2000, John
S. Denker wrote:

> This thread started out with the question of how to understand the
> "triboelectric series".
>
> Philosophical point: It is good to train students to answer the question
> that _should_ have been asked, not just the question that was actually
> asked.  This is a crucial skill in the real world, all-too-often
> undervalued in the classroom.
>
> In this case, a good move might be to morph the topic toward "work
> function."  Note that that altavista reports 5165 references to that,
> versus 93 references to "triboelectric series".
>
> Specific questions:
>
> 1) Generally speaking, what is a work function?
>
> 2) Given a chunk of lead, why is its work function not zero?  Why is its
> work function different from a chunk of gold?
>   http://klbproductions.com/yogi/periodic/
>
> 3) How might you measure the work function non-photoelectrically?
>
> 4) Does the answer to (3) tell you something about the fundamental physics
> of contact electrification?
>
> 5) What would you predict for the work function of a chunk of lead, plated
> with one or two monolayers of gold?