Chemistry in Pictures: Hardly containing the excitement

In a variation on an old favorite, Wayne State University professor Tom Kuntzleman zapped some salts to create various colors of electricity. Usually these colors are shown to students using flame tests or so-called rainbow tests. As the name implies, flame-test demos involve burning salts in air and observing how the fire changes color as the salts’ ions emit specific colors of light. The colorful emission spectra are caused by electrons in the ions briefly becoming excited by heat and then emitting light as they fall back to their ground state. Because flame tests have caused a number of injuries in the past, instructors are always looking for alternatives, like this one. Kuntzleman places his salt of choice in a vial with a bit of water and then touches an Oudin coil to a nail going through the top of a vial. The Oudin coil is connected to a power source and creates sparks that glow with colors similar to the ones the flame test would generate. The greenish blue is characteristic of copper chloride; sodium chloride, orange-yellow; and lithium chloride, scarlet.

This demo was based on a paper in the Journal of Chemical Education, and you can read that paper here.

Credit: Tom Kuntzleman, aka Tommy Technetium on YouTube and @pchemstud on X, formerly Twitter.

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