It might not seem important at face value, the researchers say, but their findings mean that these delicious bubblers can be used to test the same basic principles that govern everything from lava flow to the extraction of plasma from nuclear reactors.
Like these more dangerous fluids, melted chocolate is non-newtonian -- which basically means it flows in strange ways.
"Apart from the fact that they’re super cool and delicious, from a scientific perspective, chocolate fountains provide a really nice introduction to non newtonian fluids," said Adam Townsend, who co-authored the paper while working on his master's degree.
The idea came from his advisor and co-author, Helen Wilson, who started thinking about the behavior of flowing chocolate while on a hike one day. When she asked her colleagues in the applied mathematics department why they thought chocolate formed an inward-flowing curtain, she got a handful of different ideas -- so she decided someone should figure it out for certain.
"All of the advisers have to offer up a few undergrad projects, and there were some very technical words on that project list," Townsend said. "And then I saw 'chocolate fountain' and I said, aha! That's the one."
Townsend and Wilson set out to match up mathematical equations to the chocolatey sweet reality of a fountain. They found that the physics of chocolate curtains followed the same principles as "water bells".
"You can build a water bell really easily in your kitchen" Wilson said in a statement. "Just fix a pen vertically under a tap with a 10p coin flat on top and you'll see a beautiful bell-shaped fountain of water."
Townsend is now close to completing his Ph.D. studying fluids that he reluctantly admitted are less fun than chocolate. But he and Wilson do lectures with their fountain, using the basic principles they learned to convince kids and teens that math can be interesting.
Between the experiment and the lectures, Townsend estimates that he's bought around 100 pounds of chocolate. Throwing it away in the lab, he said, was "heartbreaking." But luckily the students he lectures to are happy to help him dispose of the stuff.
"We want them to know that math is in places you don’t expect, it’s interesting, it’s worthwhile to study it," Townsend said. "And it’s a nice thing, having a chocolate fountain at a lecture, because they come up afterwards wanting to eat some -- and then they ask questions."