Re: Wave phase reversal on reflection

[Herbert H Gottlieb <herbgottlieb@JUNO.COM>]

Few ideas, such as the one that Tom Ford wrote below,  are so elegant
and convincing to students learning physics. In over 30 years of physics
teaching, I have rarely come across such a simple model of wave behavior.
If this is original...CONGRATULATIONS TOM..... If it's not original,
let's
give our heartfelt thanks to Tom for bringing it to our attention.

All such "models" are likely to help in understanding phenomena that are
observed.   Hopefully a bright student will ask, "What makes actual water

waves turn over when they are reflected?"

Herb Gottlieb from New York City
(Where our big ocean waves teach the little ones to invert phase
whenever they are supposed to)

 On Wed, 26 Apr 2000 08:02:50 -0400 Tom Ford
<tomford@THESCIENCESOURCE.COM> writes:
> Now is the time to point out that a good way to model this behavior,
> for
> students at the introductory level, is to make a projection
> transparency of
> the wave (represented as a parade of wavefronts or a simple sine
> wave) and
> then fold the model at the proposed plane of the reflector on an
> overhead
> projector. This will also handle those interesting cases where the
> incident
> is not along the normal to the interface.
>
> Tom Ford
>
>
> At 01:34 PM 4/25/00 -0500, you wrote:
> > Remove the boundary.  The reflected wave projected past the
> boundary
> > must exactly cancel the incident wave in the region beyond the
> boundary.
> >                        Regards,
> >                                Jack
> >
> > Adam was by constitution and proclivity a scientist; I was the
> same, and
> > we loved to call ourselves by that great name...Our first memorable
> > scientific discovery was the law that water and like fluids run
> downhill,
> > not up.
> >                          Mark Twain, <Extract from Eve's
> Autobiography>
> > On Mon, 24 Apr 2000, SSHS KPHOX wrote:
> >
> > > My colleague asked if there were a good explanatiion for the
> phase
> > > reversal when a wave reflects from a boundary where the new speed
> will be
> > > less and not when going from slow to fast. I don't have one for
> her. Can
> > > anyone help?
> > >
> > > Ken Fox
> > > AP/IB Physics Teacher
> > > Smoky Hill High School, CO