This article is from the Chemistry FAQ, by Bruce Hamilton B.Hamilton@irl.cri.nz with numerous contributions by others.
This experiment consists of electrically heating a vegetable that has been
soaked in a brine solution to conduct electricity. Because this experiment
involves electricity at dangerous voltages, the experiment should be
performed on special apparatus under qualified supervision. I'm not going
to detail the equipment and procedures, as they have been described in
an Journal of Chemical Education article [8]. The experiment has not just
been limited to table salt and pickles, many other vegetables and salts
that produce different colours have been investigated and described in the
same issue of the Journal of Chemical Education [9]. People intending to
perform the experiment should obtain both articles.
 
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