Kundt’s tube

Sealed Tube Speaker System Shows off Standing Waves sans Fire, Mess

Kundt's tube is one of several classic acoustics instruments used originally to measure, and now mostly to demonstrate, phenomena related to standing waves. Unlike Ruben's tube (which uses open flame and requires a source of combustible fuel) or a Chladni plate (which uses loose fine powder) to create similar effects, Kundt's tube is both completely safe and completely clean.

The example shown here was built by San Luis Obispo resident and nuclear engineer Mike Sullivan. It consists of a clear tube with a speaker at each end containing hundreds of fluorescent plastic beads. The speakers produce two different pitches -- one (to left) fixed at A220, and one (to right) that can be varied over a range of about a half-step up or down from A220 by turning the single knob.


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4 Responses:

  1. You must be the easiest person in the world to shop for.

  2. J. Peterson says:

    The video gives me a sudden craving for Kix cereal.

  3. Adolf Osborne says:

    See also:

  4. pawliger says:

    The Exploratorium used to have a similar exhibit using water instead of styrofoam beads. Not sure it made it over when they moved to Pier 15.

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