🚀 go-pugleaf

>
> Gary:
> Would love to include the topics, but don't seem to find the time.  It
> would be appreciated if you could describe the course.
>
> Harold Lefcourt
> Morris Knolls HS
> Rockaway, NJ
>
This is the end of my first year in teaching, so I can't really balence
the amount of success I have had with this curriculum, but I can tell
you what I have done.

It is a two year curriculum.   The approach of the Science Dept at GFS
is that all the first year science courses must be accessable to all students,
thus the emphasis is put on dispelling fears about science and making science
and making science 'fun', saving the development of critical thinking for
the second year bio, chem, and physics courses.

In the first year physics course, I guess I have strayed from the narrow path
in the topics I have covered.  We spend the first quarter (8-9 weeks) on
Mechanics.  The treatment we use is Hewitt, supplemented by Hickman's workbook.
Nothing out of the ordinary.At then end of Mechanics, the students all launch
 Estes they have built and analyze the motion, and calculate the drag force.
  I then spend the rest of the semester (7 weeks)
on Electricity and Magnetism. Again Hewitt and Hickman.

Second semester is spent wholly on waves, sound and optics.  Granted I am bias,
having concentrated on optics in college, but I always found Mechanics to get
boring to the 'non-science' student if it is dragged out too long, so I save
an in depth study of Mechanics for the second year course. Same with E&M.
That way I can include the use of calculus.

So when we start out second semester, we spend a couple weeks looking at
ropes, slinkies and ripple tanks.  From there we approach sound, doing alot
of work with the oscillascope.  We play different instruments into the scope
and use a systhesizer.  The violin works nicely for showing resonace on
a string, because you can change the tension in the string, the length
of the string, etc.  The trombone works nicely to show the principal of
overtones.  SO we spend time on resonant cavities.

The next step is analying sound and Fourier Transforms.  From my college
experience, this was the hardest thing for me to get a grip on, but that
is because it was never explained with a physical example.  SO I show
the students how by adding different SIN waves together they can
produce sqaure, sawtooth, and triangle waves.  Most of the students have
the programmable graphing calculators, so I have the students add the
SIN waves to produce their own sqaure waves, etc.  Thus I get the idea
of the Fouier Transform across.

We finish sound by discussing methods of converting electric signals to
sound and back again, which the students are very interested.  Digital vs
analog, tapes, 8-tracks, CDs, etc.

The next topic is lasers.  I first introduce light as both a particle and
a wave.  Then a bit of quantum theory, so they understand the idea of
energy levels.  Once they have this idea down, we cover how a laser works.
The basics of spontaneous and stimulated emmission, and pumping the medium.
We then talk about the laser being a resonant cavity, except for light
instead of sound, and how it can resonate at several modes.  From there
we go into line broadening, which reintroduces the doppler shift, which
they learned when we studies sound.

Next we observe what can happen to the laser beam, ie the basics of the
old classical optics curriculum, except the labs are done with laser
beams instead of the traditional push pins, which I feel adds a lot of
flair to the labs, and the kids love the lasers.
Now I know you probably are all thinking, how can I afford so many lasers.
Truth is, I couldn't if I bought them new. But you can buy kits to assmeble
He-Ne lasers for $50 a pop, which is a lot less than the $460 you'll pay
Metrologic for  a new laser.  I'll be giving a paper at Notre Dame on how
to build a laser.

When doing the labs, you can buy a fog that illuminates the beam in the air so
 the students can see it.  Same stuff that is used in laser light planetarium
shows.
After classical optics, I cover diffraction, but introduce it as a Fourier
Transform.  So the Fourier Transform of an image is a diffraction pattern,
and if we take the diffraction of that pattern we get the original image
back.  There is a phenominal demonstration for this done by focusing the
diffraction pattern of a target down with a lens to produce the original
image.
This naturally leads into the end of my course which is holography, which
is based on diffraction patterns.  For the end of the course, all the
students are required to get into the lab and attempt to produce a hologram.
It was our first year, and we had a 60% sucess rate at making the holograms,
which were very bright and nice.  Not bad considering the photometer I
have measures in units of footcandles and I have no clue how to calculate the
exposure time.

That's it, I welcome comments and critisism.  Has anyone else done anything
innovative with optics, and if so, what kinds oflabs do you do?

Cheers,

Gary Garber
Germantown Friends School
31 W. Coulter St.
Philly, City of Brotherly Love
215-951-2300