Why do whole oranges float, but peeled oranges sink?

Go check out the courses on Brilliant! https://brilliant.org/standupmaths Be one of the first n people (for n = 200) to sign-up for a free Brilliant account and get 20% off if you upgrade to paid membership. Here is the original QI tweet: "A whole orange will float on water, but a peeled orange will sink." https://twitter.com/qikipedia/status/970177018561286144 Orange: 246.3g Peel: 97.9g Orange displacement: 231.2g Peel displacement: 109.4g Total Orange: 344.2g Total displacement: 340.6g If you make your own measurements with an orange: send them in to me! [email protected] CORRECTIONS - None yet. Let me know if you spot anything! Thanks to my Patreon supporters who make these videos (and currently: projects to find psychic pets) possible. Here is a random subset: Lachlan Churchill William Clark Scott Rosenblatt Ivik Injerd David Kidd Support my channel and I can make more videos: https://www.patreon.com/standupmaths Music by Howard Carter Filming and editing by Matt Parker Design by Simon Wright MATT PARKER: Stand-up Mathematician Website: http://standupmaths.com/ Maths book: http://makeanddo4D.com/ Nerdy maths toys: http://mathsgear.co.uk/