The Glowing Pickle

Q. If you hook up a pickle to a 110V power supply and then turn the electricity on, the pickle starts to glow with a yellow color. Why might this be happening? HINT: Pickles are made by soaking cucumbers in very concentrated salt solution.
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A. If you dip a clean wire into a clean salt solution and then place it into a flame [with precautions to protect your hand], it glows yellow because of the sodium in the salt. Sodium outdoor lights produce yellow light also by heating sodium vapor to a very high temperature.

The strange thing about the glowing pickle is that it is not very hot. Attempts to explain the yellow glow contain assumptions that have not been proven. Most of them assume that sodium atoms in the salt somehow become activated enough to give off yellow light. That sounds very reasonable and it is probably correct.

The problem is explaining the activation of sodium without raising the average temperature of the pickle very much. The water in the pickle is not even boiling. Yet, sodium atoms become activated enough to produce the yellow-orange glow.

Some Internet sites post explanations that promote the idea of mini electric arcs within the pickle: Multiple electric sparks jumping across little spaces formed by steam inside the pickle. However, no serious, systematic experimental study has been undertaken to solve the glowing pickle mystery. Take a look at the web pages below and the links in those pages:

http://www.exo.net/~pauld/activities/aaptelectric/glowingpickle.html

http://www.winzy.com/word/Pickle%20Light%20Experimen

http://home.nycap.rr.com/useless/pickle/index.htm