Science

So it turns out, happily, that the mercury beating heart demo I wrote about a couple days ago can also be done with molten gallium, which is vastly less toxic than mercury and requires only slightly higher temperatures. The chemists at the University of Nottingham who produce The Periodic Table of Videos made this very informative video demonstrating the process, which is slightly different from the mercury beating heart demo in that there is no iron nail present. The gallium blob “beats” anyway, but much slower than the mercury with the nail. I bet using a nail would make the gallium version beat just as fast. [Thanks Filip!]

There are, however, 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?