They plop, they bubble, they smell amazing, they can colour your bath water into a rainbow of colours. And now you can make these little lumps of joy at home. Subscribe for regular science videos: http://bit.ly/RiSubscRibe Bath bombs are surprisingly simple to make. Using just citric acid powder, bicarbonate of soda and water, you produce that vigorous fizzing reaction. --- A very special thank you to our Patreon supporters who help make these videos happen, especially: Ashok Bommisetti, Avrahaim Chein, Greg Nagel, Lester Su, Rebecca Pan and Will Knott. --- The Ri is on Patreon: https://www.patreon.com/TheRoyalInstitution and 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