glowingpickle

Glowing Pickle

Glow little pickle, glimmer, glimmer...

Introduction

When a high voltage is applied across a pickle the pickle will emit a yellow glow.

Warning! This is a dangerous, possibly deadly activity. We publish it to show a safer way of doing the experiment using a ground fault interrupt. Do not do it unless you use the ground fault interrupt circuit we introduce below, and unless you are skilled in working with potentially lethal voltages of alternating current.

Material

A GFI protected 110 volt AC power source.
An apparatus for applying 110 volts AC across a pickle including skewers which penetrate the pickle.
A pickle

Assembly

Attach a power cord to a GFI wall outlet. I mount the outlet in a plastic box for protection.

Build a circuit containing two metal shish-kabob skewers.
Attach these skewers to a PVC frame.
Insert the skewers into a pickle.
(A "death cord" connects a 110 volt AC power plug to two alligator clips.)
Make sure a "death cord" is not plugged in to anything.
Clip the alligator clips of the "Death Cord" onto the skewers.

To Do and Notice

Plug the "death cord" into the GFI outlet.
Make sure no one is touching the pickle.
Plug the GFI outlet into a wall socket.

Wait a few minutes.

Notice the pickle begins to steam.

Then it begins to flash bright yellow at one end.

If you look at the yellow light with a spectroscope you will see that it is the yellow light of the sodium D line.

What's Going On?

The electric current flowing through the pickle heats the water in the pickle above the boiling point near the skewer electrodes. The steam leaves the pickle, drying out a region near the electrodes.

When a dry region completely envelopes one electrode, a spark leaps between the electrode and the still wet region nearby. This spark is in an environment rich in salt water. The spark excites the sodium to emit yellow light. The sodium D-line.

Going Further

If you soak the pickle for a week in a brine made with Salt Substitute,potassium chloride, the yellow glow will be replaced by a pink glow from the potassium.

Use several pickles, does the same end always glow?
(Not for us particularly if we use new skewers each time.)

Return to Draft Activities