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Discussion about yesterday’s mercury “beating heart” reaction post got me thinking about chemical oscillators in general. Turns out, the mercury beating heart may be the only mechanically oscillating chemical reaction that anybody knows about. It’s certainly the only one I know about, and its the only one I can find on the web. But if you know of another mechanically oscillating reaction, do please drop me a comment. However……there are other oscillating chemical reactions. None of them result in mechanical action, but the cyclical color changes of, for instance, the Briggs-Rauscher reaction (shown above) are pretty cool in and of themselves. The prototype chemical oscillator is the Belousov-Zhabotinsky reaction (Wikipedia) which was only discovered in the 1950s. For years, no respectable journal would print reports of oscillating chemical reactions because many editors could not reconcile their understandings of thermodynamics with the notion of an oscillating reaction. Guess who had to eat crow?

Thanks to YouTuber groswilly for the above footage.

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.


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Comments

  1. Fred says:

    my chemistry prof’s thesis was on the “Beating chicken fat heart” experiment. He described a phenomenon where fat, under certain conditions, would get more or less viscous. The oscillating viscosity caused a “beating heart” looking thing. Similar to the mercury one, but it doesn’t require an iron nail. And it works a little differently.

    1. Sean Michael Ragan says:

      Cool! That sounds perfect. I don’t suppose there’s some way I could contact your prof? Or you could just tell me where he did his thesis as it’s probably still on file there. If you are inclined. Feel free to e-mail me directly at sean@makezine.com.

      Thanks a bunch!

  2. Jonathan says:

    I believe Sodium and probably other alcali metals can bounce on the surface of water, but not necessarily for very long.
    Then it either fades away or blows up (sort-of)…..

    Does that count?

    1. Sean Michael Ragan says:

      I would say yes, that counts, in principle. And it suggests some general features such a system might have: a reactive material, which is brought by gravity (or perhaps spring-power) into contact with a reagent and is then separated from it again by the energy of their reaction, which then subsides and allows gravity (or the spring) to reunite the materials.

  3. Jan says:

    There are effects based on oscillating burning in fireworks. For example whistle-mix (whistling rockets) and strobe compositions (strobe pots, strobe stars,…) For more informations try to find book: Fireworks the Art Science and Technique by Takeo Shimizu.

  4. Filip says:

    There is a similar reaction with gallium. Molten gallium is placed in sulfuric acid with an oxidizer and the blob of gallium acts just like the mercury in this video.
    Check it out on periodic table of videos:
    http://www.periodicvideos.com/videos/031.htm

  5. Ruth Shear says:

    What ? No shout out to good old pchem lab? I loved that oscillating reaction experiment. When it worked.

    1. Sean Michael Ragan says:

      Yo, Doc Ruth, up in the hizzy! U.T. P-CHEM 4-EVA BABEEEEEEEE!

      =]