Place the pickle across the
electrodes and turn on the outlet strip. The pickle
conducts because of the salt solution and will eventually glow
yellow. The glow is due to arcing across gaps of vapor
where the pickle has dried out near an electrode. Sodium
D lines can be seen with a diffraction grating.
NOTES
Use caution around
exposed 120 V electrodes. Plug the apparatus into an
outlet strip with a GFI, a switch, and an indicator light.