Marvel in awe at the swirly, hypnotic recrystallisation of 4-hydroxybenzaldehyde. The magical effect above is triggered when a flask of the reddish solution is dunked into an ice bath, and the chemistry going on behind the scenes is pretty damn cool.
As you can see in the video above, which was uploaded by scientist Christopher Lyon, the solution starts to become taken over by a white, smoky solid as it cools down. So what's causing this mystical health potion cloud to form? As Lyon confirms over on reddit, the solvent in the flask is barely soluble at room temperature, and, as it begins to cool down in the bath, the solute starts precipitating out, producing the solid you see swirling around the bottom.
Understanding the reaction only makes the whole thing more mesmerising to watch… over and over again.
Source: Christopher Lyon