Leicester University study disproves Giant Peach's flight of fantasy

Roald Dahl may famously have written that it took 501 seagulls to help James fly the Giant Peach – but a group of physics students have concluded that the actual figure would be a lot more.

Calculations by Emily Jane Watkinson, Maria-Theresia Walach, Daniel Staab and Zach Rogerson show a total of 2,425,907 seagulls would be needed to lift the peach into the air.

The University of Leicester fourth year physics students were inspired to use the childhood tale, which has delighted youngsters across the world since it was first published in the 1960s, as the basis for a scientific paper.

The story sees a young boy named James embarking on a journey across the Atlantic Ocean on a magical peach, the size of a small house.

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Emily Jane said: "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.

"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."

The group first calculated the potential weight of the peach, using measurements based on the size of a small house, as described in the book.

By multiplying its density by its volume, and using Newton's famous second law of motion, they arrived at a figure of 4,890,579 Newtons – the amount of force it would take to move the peach.

Next, they worked out how much weight each seagull could lift based on its wingspan, the density of air around it and the speed it would travel. They calculated this at just over two Newtons – allowing them to work out how many it would take to lift the peach.

"It showed us that 501 seagulls would be nowhere near enough to lift the peach, and that it would take much more – nearly 2.5 million seagulls to do this," said Emily Jane.

"We've all had a brilliant time working on this project. It's been lots of fun, and it's been great using Roald Dahl's story as inspiration. It's also helped show us how to write a proper scientific paper."

Course leader Dr Mervyn Roy, a lecturer at the university's department of physics and astronomy, said: "A lot of the papers we published are on subjects that are amusing, topical, or a bit off-the-wall. Our students are nothing if not creative.

"But, to be a research physicist you need to show some imagination, and this is something that the module allows our students to practice."

How James came across the Giant Peach

James and the Giant Peach, by Roald Dahl, is the story of a young boy called James, who lives with his parents until his world is turned upside down when they are eaten by an escaped rhino on a shopping trip in London.

James is forced to live with his cruel aunts, Spiker and Sponge, who live on a desolate hill near the white cliffs of Dover.

One summer afternoon, James stumbles across a strange old man who gives him a sack of tiny glowing-green crocodile tongues. He promises that if James mixes the contents of the sack with a jug of water and 10 hairs from his own head, the result will be a magic potion which, when drunk, will bring him happiness and great adventures.

However, on the way back to the house, James trips and spills the sack on to the peach tree outside his home.

The tree becomes enchanted and begins to blossom – creating a giant peach.

The aunts discover this and make money off the peach, while keeping James locked away. At night, he is forced to collect rubbish from the crowds who gather to see it. But one night, he ventures inside a tunnel in the peach which leads to the hollow stone in the middle. Here, James discovers a band of insects, also transformed by the magic of the green tongues. A centipede bites through the stem of the peach, releasing it from the tree, and it begins to roll down the hill, squashing the aunts. It rolls through villages and a famous chocolate factory, before falling off the cliffs and into the sea – where their adventures begin.