During long, cold winters in medieval Europe, church organs grew gray, sickly-looking circles that spread over their pipes. People back then believed that this was the work of the devil, but as it turns out, it’s just some pretty simple chemistry.
Hosted by: Stefan Chin
SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at http://www.scishowtangents.org ---------- Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow ---------- Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever: