All,
Perkins Observatory has just been promised a modest grant to construct some
exhibits about stellar spectra. I have a few ideas I'm working on for
this, and wanted some opinions on them. Also, if there is anything obvious
that I've failed to think of, please let me know!
Also, I have a couple of questions about my ideas which I could use help
with. See below.
1) White Light Spectra
Push a button and a white light source (a slide projector) comes on. The
projector contains a slide with a narrow slit, which passes through a
prism, making a rainbow on a small screen.
2) Color Mixing
Designed to drive home the point that white light is a mix of colors.
Three small projectors produce overlapping circles of green, blue, and red
light. The intensity of the three lights can be controlled with knobs.
When all are at equal brightness, a small triangular area of white light is
seen. The projectors, BTW, are visible to the public so they can see that
there are only the three and not a hidden "extra" one making the white
light.
3) Spectral Lines
The standard. Press a button, and a spectral tube lights up. There are
four different tubes located behind a diffraction grating. Also, there is
a fifth tube without a label on it which is identical to one of the other
four. Guests try to guess what it is by lighting it, then lift a flap to
see the answer.
4) Doppler Shift
Sound is used to illustrate the Doppler effect. A 15-foot long track
sits along one wall with a speaker attached to it. In the center of the
track is the console with two buttons. Press one, and the speaker sends
out a steady tone for 10-15 seconds. Press the other button and the
speaker sends out the same tone, but now it moves quickly along the track
from one end to the other.
5) Visible vs. IR light
This is the centerpiece of the exhibit. A table and chair sit in front
of a pair of TV monitors. Two cameras are pointed at the chair, one that
sees visible light, and one that sees in IR. The guest can see him/herself
on both monitors. The table also has a pair of lamps. One with an
ordinary incandescent bulb, and one with a cooler compact fluorescent. The
different temperatures of the bulbs should be obvious.
Questions:
How much does a _GOOD_ IR camera cost, and where can I get one?
Night-Vision type cameras are NOT acceptable, because they don't really
show differences in temperature, in my opinion. Recently, I visited the
new Cleveland science museum, and they have a very nice one there that
would be perfect. Is anyone on the list from the Cleveland museum? Anyone
have a contact?
I have also seen IR cameras used to create false-color images where hot
sources appeared red, and cool sources were blue. Any idea where to get
something like this or set it up?
I'll need a couple of nice video monitors. No sound output or TV reception
necessary, of course. Sources anyone?
Does anyone have a good source for a cheap, LARGE piece of diffraction
material? 2' x 2' at least. It doesn't need to be of research quality,
obviously, just good enough to see the lines. Edmund Scientific seems a
bit pricey to me. Any better places?
-------------------------------------------------------------------
Bob Martino "I look up to the heavens
Assistant Director but night has clouded over
Perkins Observatory no spark of constellation
no Vela no Orion."
http://www.perkins-observatory.org -Enya
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