Don't go looking for Gillyweed anytime soon
Credit: Murray Close

The Harry Potter universe is full of all sorts of magical creatures and spells, the kind that expand young readers’ imaginations and reimagine the dreary world of British boarding schools with colorful fantasia. The beauty of the wizarding world is in the impossibility of its magic. But that didn’t stop two U.K. scientific journals from recently investigating the scientific possibility of Gillyweed and Skele-Gro.

Rowan Reynolds and Chris Ringrose in the peer-reviewed Journal of Interdisciplinary Science Topics estimate that since Harry’s gills appear to be 60 square centimeters in surface area, he would need to process 443 litres of water at 100 percent efficiency to make Gillyweed, the magical plant Harry uses to breathe underwater during the Triwizard Tournament in Goblet of Fire, work. Unfortunately, in David Yates’ film adaptation of Goblet of Fire, Harry spends most this time swimming with his mouth closed – not very efficient.

“In the film, Harry is frequently seen swimming with his mouth closed, which is not how fish use their gills,” Reynolds and Ringrose write. “If Harry were to open his mouth to allow water into his throat and out through the gills, it may be plausible that he could breathe underwater. However, without doing this, it is simply not plausible that he could extract sufficient oxygen for survival.”

As for Skele-Gro, the potion Madam Pomfrey uses to regrow Harry’s bones after they’re removed by Gilderoy Lockhart in Chamber of Secrets, a different team for the same journal found that the energy requirement for such regeneration would be massive. Regrowing all the bones in Harry’s arm in such a short time (Madam Pomfrey provides the Skele-Gro at 11:50 a.m. on a Saturday in J.K. Rowling’s book, and Harry is fully healed by Sunday morning) would require. Since there’s no mention of the bed-ridden Harry eating during that time, the extra energy must come from the Skele-Gro itself.

“Skele-Gro therefore must contain unexplained magical properties that allow it to hold such a vast amount of energy and indeed be able to apply it in a short period of time,” the researchers write.

Sorry to disappoint hopeful Harry Potter fans, but don’t go looking for real-life Gillyweed anytime soon.