Pop: the science and sound of popcorn
February 11, 2015
Ever wondered why popcorn makes a popping sound?
How often have you thought it's because the popcorn hits the pot during cooking?
Well, researchers in Paris say they have the real reason.
They say the popping sound is caused by the sudden escape of evaporating water when the cooking husk cracks at 180 degrees Celsius.
"So far, there have only been commercial studies on popcorn, so we were eager to look at the phenomenon scientifically," says Emmanuel Virot of the Ècole Polytechnique in Paris.
Virot is one of the study's leading researchers. Their study is published in the "Journal of the Royal Society Interface."
A series of tests
He and his colleague, Alexandre Ponomarenko, monitored the popping process with a high-speed camera, taking more than 10,000 pictures per second.
They were able to link the popping sound to the moment when the water vapor inside the kernel is hot enough to force open the surrounding shell.
But that is not all.
Next they discovered that popcorn wouldn't be popcorn without somersaults.
The kernel is transformed into the shape of popcorn (as we know it) by doing one-and-a-half somersaults. A starch leg forms at the bottom of the emerging popcorn to make the jump possible.
Popular snack
People have eaten popcorn for more than 9000 years.
But why would you bother to run scientific tests?
The popcorn project is not the first unusual take on scientific research conducted by Ponomarenko and Virot.
In 2013, their study of the sound of thirsty trees grabbed the global attention.
And they are hoping for the same with their popcorn reseach.
"As we started to observe popcorn explosions, it turned out that this phenomenon contains interesting physics from different scientific fields: thermodynamics, biomechanics and acoustics," Virot says.
They say popcorn has a very unique way of jumping - halfway between plants and muscle-based animals, such as human beings - which makes it worth analyzing.
Their videos show the kernels jumping in different ways.
Virot says the project aims to link science with real life and make it easier for students to understand complex science.
And it's tasty.