Think Again, Roald Dahl: Scientists Hit on Giant Peach of a Theory

(from The Guardian
by Alison Flood)

Roald Dahl was many things – a twisted literary genius, a bestselling author and a creator of enduring characters including Matilda, Willy Wonka and Danny the Champion of the World. But did he pay close attention to the realities of science and nature? No, he did not, and his lack of adherence to the facts of life has now been uncovered by a group of physics students from Leicester University.

Growing suspicious at Dahl's claim that it took just 501 seagulls to lift James's giant peach into the air – "I shall simply go on hooking them up to the stem until we have enough to lift us. They'll be bound to lift us in the end," says James – the students decided to test the author's theory. Their scientific paper first calculated the potential weight of the peach – it is "as tall and wide, in fact, as a small house," writes Dahl in the children's novel – and then multiplied its density by its volume, concluding that 4,890,579 newtons of force would be needed to move the peach. They calculated that each seagull would be able to lift just over two newtons, and that a total of 2,425,907 seagulls would actually be required to lift the peach off the ground.

"Through examining the buoyancy and modelling the seagulls as aerofoils it has been found that although the initial part of the journey is possible, given a sufficiently hollow peach James would have to tether approximately 2.5m common gulls, rather than the 501 as described in the book," they write in their paper.

"Our degree encourages us to learn and apply real principles of physics to new and imaginative topics, and as all of us knew the story and I particularly loved it, we thought it would be a great idea to use it for our paper," Emily Jane Watkinson, who worked on the project with Maria-Theresia Walach, Daniel Staab and Zach Rogerson, told This Is Leicestershire.

"Earlier in our degree, we studied the physics of aircraft and specifically what it takes to get them into the air. We thought it would be fantastic to apply that knowledge to the giant peach."

James and the Giant Peach tells the story of the lonely James, living with his nasty aunts Sponge and Spiker. When he pours a magic potion on a peach tree by their house, it grows to enormous proportions, and James then escapes Aunt Sponge and Aunt Spiker on the giant peach, embarking on a series of adventures with his insect companions.

The precise scientific makeup of the potion has yet to be analysed, and it is not yet known how George's medicine managed to successfully grow and shrink his grandmother, nor what exactly was going on when Matilda moved objects with the power of her mind.

*note-how funny I just mentioned this author the other day in talking about the books my uncle used to send. I guess I would not have thought of it that young but it is funny someone actually did the math or the equation to see how many birds it would take to lift the giant peach. This was a cute article.