The iodine clock is a common chemistry experiment in which two clear liquids are mixed together to produce a dark, opaque color. But as you'll see in this video, the speed at which this reaction happens is nothing short of remarkable.
This effect is the result of two different reactions, with one being exhausted more quickly than the other. The experiment can be run a number of ways; typically, the first liquid is comprised of hydrogen peroxide and sulfuric acid, while the second consists of potassium iodide, sodium thiosulfate, and starch.
The producer of the video, Brusspup, explains more:
There are no editing tricks in the video. All of the reactions that you see are uncut and play at the original speed...
...You can order clock reaction kits from several science related websites. You can also use simple store bought chemicals like vitamin C, iodine, hydrogen peroxide and starch. A quick internet search will turn up multiple ways of performing the experiment.
Even though I've played around with the clock reaction experiment before I've always wanted to capture the reaction as the liquid was being poured. To me, this is the most stunning way of demonstrating the reaction.