From: pauld@exploratorium.edu
Date: Mon Mar 27 2000 - 23:13:33 PST
Message-Id: <200003280713.XAA00469@isaac.exploratorium.edu> From: pauld@exploratorium.edu Subject: Re: pinhole laser jello neat effect Date: Tue, 28 Mar 2000 07:13:33 GMT
Gene
Good observation.
The helium neon gas laser excites the neon with an electrical discharge. The
neon responds by emitting all of its spectral lines. The laser amplifies one of
these lines, usually the red one, although you can also get green helium neon
lasers from Metrologic. However if you dim down the laser emission which the
blue jello does, then you can can see the other colors of light emitted by the
neon (and helium too.)
Paul D
> Hello all, I have been doing the Laser Jello snack in my classes.
> During this, I brought in several types of Jello. While all the colors
> we used had explainable results, the blueberry had an interesting
> result. It seems that a large percentage of the red laser light
> reflected and the rest was absorbed. However, several of my students
> noticed that a faint blue non-lazing(sp? or real word?) light went
> through the jello and could cast very good shadows of jello defects and
> bubbles. When looking at the lasers (meterlogic neon) through the
> jello, there was a tiny spect of red laser light surrounded by a blue
> "halo" or circle. We sent this light through a diffraction grating and
> got very very faint first and second order maxima.
>
> My questions are these:
>
> Are we seeing the blue spectra from neon by doing this?
> Have others seen or done this?
> Do other colors of jello (grape?) give the other spectral bands?
> Are there other things your students have noticed doing this lab?
>
> By the way, Jello Jigglers can be easily removed from petri dishes after
> two weeks in the fridge! LOL!
>
> Thank you,
> Gene Gordon
>
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