Re: Student question/trioboelectric series

[Joseph Bellina <jbellina@SAINTMARYS.EDU>]

I think the presentation in Sherwood and Chabay which suggests that the
tranferred materials are ion fragments rather than electrons is probably
a more correct model.  The point they make (and I really shouldn't speak
for them...look on or about page 16 of their text) is that these
materials are mostly polymers so it is easy to imagine ion fragments
being transferred.
Recent work modelling what happens when metals touch indicates that
there is material exchange, but I don't know if the role of charge has
been considered.
These ideas are all well and good, but a detailed quantitative model has
not been developed...and some of the best surface theorists have
addressed the problem...Xerox, for instance, would like very much to
understand it better.

In terms of doing something in the lab empirically, any experiment that
gives consistent reproducible results...well reproducible enough...is
fine to do...just be careful what inferences you make from those
results.  I see vague model statements in Hecht...I'd prefer he didn't
make them...I ignore them.

The original question was about the model one uses to explain the
observation, and that is what my comment was about.  Hecht speaks in
terms of electron transfer, Chabay and Sherwood in terms of ion
transfer...neither is very quantitative.

enjoy

On Tue, 18 Apr 2000, Hugh Haskell
wrote:

> Joe, your reply sent me off to my collection of introductory physics
> texts. I thought maybe I had misremembered the name of the phenomenon
> I was thinking of. It isn't a widely discussed subject, I will admit,
> but I did find a reference to it in Hecht's calculus-based text (p.
> 647, in the1996 edition) and I had remembered it correctly, as least
> as correctly as Gene Hecht had. While making up a definitive list may
> be difficult, this is a lab exercise we have our students (11th and
> 12th graders) do every year, with a few objects (Saran wrap, rabbit
> fur, plastic, Scotch tape, Styrofoam, wool, and a few others). Their
> task is to arrange the objects they are given in an order such that
> the object at the top of the list will transfer electrons to any
> object below it on the list, the one on the bottom will pick up
> electrons from any one on the list above it, and those in between
> will give up electrons to those below and accept electrons from those
> above (I think that's the normal order). According to Hecht, this is
> called a triboelectric series, and that's what we have called it for
> at least 15 years.
>
> Have we been doing it wrong, all these years?
>
> Hugh
>
> > This is one hell of a problem, which I explained to him off the
> > net. Currently there is no good answer to his question, and the
> > experiments are very difficult to do, and cost lots.  If you want to
> > send someone off to work on a project, think about the project and what
> > a student might be able to do before you launch them.
> >
> > Good idea in principle, but not for this topic.
> >
> > cheers
> >
> > joe
> --
>
> Hugh Haskell
> <mailto://hhaskell@mindspring.com>
>
> Let's face it. People use a Mac because they want to, Windows because they
> have to..
> ******************************************************