What is an explanation of an electrical pickle?

Question

My 11th grade class just did an experiment called the electrical pickle. Why does the pickle glow a fluorescent yellow. And why does it glow at all?

Answer 1

Seems to be some debate on the issue -- either the glow is caused by an electric arc within the pickle or it is caused by the excitation of the sodium atoms in the pickle, which then emit light as they fall back to their natural state.   Apparently there has been some significant research on the subject (see the second link).