YouTuber shows how zinc oxide changes color when heated and then changes back

In this video by the YouTube channel The Action Lab, who's become a household name for conducting the coolest science experiments, you can see how zinc oxide changes color when heated and then changes back when the heat is reduced. This process involves the material basically "un-burning" itself. But how does that work?

In case you didn't know, zinc oxide is a white, relatively inert chemical that is commonly employed as a bulking agent or filler, as well as a white pigment, according to European Commission. It can be found in some rubber, glass, and ceramic products. It is also used as a catalyst in the chemical industry, and in paints as a corrosion inhibitor to reduce mildew.

If you're curious to see how zinc oxide manages to un-burn itself, make sure you watch the video above. Then, you can watch this video by The Action Lab, in which he demonstrates how he boils water with his bare hands. That hand-boiling experiment really has to be seen to be believed.