🚀 go-pugleaf

   Last fall there was an exchange on either phys-l or physhare about
the "electric pickle".  I can't remember which, so I thought I'd send
this to both in case anyone is interested.
   I just did the electric pickle in my second semester general
physics course a couple of weeks ago as part of a lab exercise on
spectroscopy.  I had the students observe several light sources
through Project Star spectroscopes and record the wavelengths of
the lines in the spectra.  The sources included both low pressure
and high pressure sodium vapor lamps.  After they had looked at
the lamps, I turned down the lights in the room and had the students
observe the glow from the end of a big dill pickle as I electrocuted
it.  They discovered that the yellow glow was at the same wavelength
as the yellow light from the low pressure Na lamp, and they all
concluded that the pickle must contain Na.  They really seemed to
enjoy that part of the experiment.  (These are college students, and
it's hard to get them excited about anything.)   I'm grateful to whoever
it was who started the discussion about the electric pickle.  The next
time I do this, I'm going to raid the chemistry stockroom and soak
some cucumbers in a variety of salt solutions so we can observe
other colors besides yellow.

Steve Luzader
sluzader@fre.fsu.umd.edu