London: Harry Potter undergoes two magical biological transformations in the popular eight-film series based on the stories and characters created by British author J.K. Rowling. Natural sciences students have now put these 'mysterious' powers to the test to find out whether these are actually scientifically feasible. In "Harry Potter and the Goblet of Fire", Harry passes the second 'Triwizard' task by consuming 'Gillyweed', which allows him to breathe underwater by causing gills to grow on his neck. To check the feasibility of Harry surviving with home-grown gills, University of Leicester students Rowan Reynolds and Chris Ringrose estimated the gills to be approximately 60cm2 in surface area based on their appearance in the film. Taking into account the oxygen content of the 'Black Lake' and the maximum oxygen use of swimming, they then examined Harry's weight, suggesting that if he had a normal BMI and the average height of a 14-year-old boy, he would need to process 443 litres of water at 100 percent efficiency per minute for every minute he was underwater. This would mean the water would have to flow at 2.46 metres per second -- twice the velocity of normal airflow and therefore far faster than he could inhale and exhale, causing him to suffocate, the students said in a paper for the Journal for Interdisciplinary Science Topics. Moreover, Harry is seen swimming with his mouth closed, which is not how gills work -- the students suggest that if Harry were to open his mouth to allow water into his throat and out through the gills, it may be plausible he could breathe underwater. By keeping his mouth shut, however, he would not be able to extract sufficient oxygen for survival, and as a result would lose his title as 'The Boy Who Lived' quite quickly after suffocating, the study concluded. In a separate study, students Leah Ashley, Chris Ringrose and Robbie Roe set out to test the feasibility of Skele-Gro, a potion which repair broken bones. In "Harry Potter and the Chamber of Secrets", Harry's tense Quidditch match against Slytherin results in one of his arms being broken by a rogue bludger. After his broken bones are removed, Harry is given a dose of Skele-Gro to grow bones that are missing. The team calculated how the rate of normal bone growth compares to this accelerated growth, and how much energy Skele-Gro would need to provide in order to rebuild Harry's broken arm. The students calculated the time taken for Harry to regrow all the bones in his arm with Skele-Gro as being at least 90 times quicker than is possible in real-world bone regeneration. As Harry's recovery with Skele-Gro takes approximately 24 hours and there is no mention of him eating during recovery, Skele-Gro has the capacity to supply the additional 133,050 kcal worth of energy required by the body to regenerate bones without causing any negative side effects, a power output of 6,443 W. The students concluded that Skele-Gro must therefore contain unexplained magical properties that allow it to hold such a vast amount of energy and be able to apply it in a short period of time. Both the studies reveal that a little magic might indeed be required in both situations to make them scientifically feasible.