Alkali Metals in Water Explode; No One Knows Why
This one used to be settled science. Alkali metals, such as cesium and potassium, would interact with water, release hydrogen vapor, and burn so hot they explode. Definitely cool, but not deeply mysterious.
Enter popular YouTube vlogger Thunderf00t. As a working scientist, Thunderf00t couldn’t leave well enough alone and started fooling around with alkali metals. When he did, he discovered a few things that nobody had noticed in the 200-odd years chemists had been performing these reactions at parties. For one thing, the metals burn under an argon atmosphere, making a rapid oxidation unlikely.
For another, they explode way too fast for this to be a conventional combustion reaction, hinting at some unusual movement of atoms. For still another, at one point in the reaction, the little blob of metal turns completely transparent like glass before exploding. Watch this clip and put on your thinking cap. If you can figure out why it behaves this way, there might be a Nobel Prize in it for you.
Briggs-Rauscher Cannot Make up Its Mind
One of the kookier types of chemical parlor tricks is what’s known as an oscillating reaction. As the name implies, these reactions switch from one state to another and back again. Perhaps the best of these, Briggs-Rauscher, can switch from colored to clear and back again upwards of ten times before the reaction is exhausted.
It isn’t especially useful, but set designers might want to consider this sort of thing for the background of the next mad scientist-laboratory movie. At least it’s cooler than dry ice bubbling in a beaker.