In the 1950s, Russian chemist Boris Belousov reported a bizarre reaction. A reaction that oscillates bet’’t seem to make up its mind. As two liquids are mixed together, a colour change occurs, then reverses, then happens again, then flips back… What’s going on? Could this seemingly spontaneously reversing reaction be violating the second law of thermodynamics? Chemist Andrea Sella demonstrates the startling Belousov–Zhabotinsky reaction and explains why, in the end, no laws are broken. The 2016 advent calendar explores the four laws of thermodynamics with a new short film each day, with explosive demonstrations, unique animations, and even a musical number. Open the calendar at http://www.rigb.org/christmas-lectures/supercharged-fuelling-the-future/thermodynamics-2016-advent-calendar?utm_source=youtube&utm_medium=social&utm_campaign=201612_channel_advent Subscribe for regular science videos: http://bit.ly/RiSubscRibe The Ri is on Twitter: http://twitter.com/ri_science and Facebook: http://www.facebook.com/royalinstitution and Tumblr: http://ri-science.tumblr.com/ Our editorial policy: http://www.rigb.org/home/editorial-policy Subscribe for the latest science videos: http://bit.ly/RiNewsletter