Right up until the 1950s, the lemon-lime soda 7-Up contained lithium citrate. This chemical compound is probably best known for its use in psychiatric medication as a mood stabilizer for people suffering from bipolar disorder.

Of course, nowadays 7-Up is free from psychoactive substances. However, the guys from the YouTube channel Periodic Videos wondered what would happen if you added the chemical element lithium to the modern-day 7-Up recipe.

The result is the rather unexpected chemical reaction. To get to the bottom of it, Sir Martyn Poliakoff guides you through some of his finest investigative science.