Credit: ©iStock.com/kazoka30
Physics can be mouth-watering. Think of the sizzle as chips deep-fry. Turns out there are 3 kinds of sizzle sounds! Can you read this without getting hungry?
The crunch
An international team of scientists wondered about a classic cooking technique from Asia. Cooks test if the oil is ready to deep-fry with the wet tip of a bamboo chopstick, watching the bubbles that form and listening to the sizzle they make.
“We couldn’t find any detailed scientific explanations,” says team member Professor Zhao Pan from the University of Waterloo in Canada. “We set out to provide one.”
What’s more, the team were surprised by just how complex sizzle is. They went on to record and analyse it in detail!
Bubble types
The researchers used millimetre-sized water droplets. With microphones and high-speed video, they recorded how the droplets reacted in oil at temperatures up to 210 °C.
The heat of the oil vaporises the liquid droplets into gas bubbles. The hotter the oil, the faster the water evaporates. Frying becomes wild bubble dynamics with splashes and jets of oil!
The team found 3 distinct types of bubble formed: explosive, elongated (long and thin) and oscillating (growing and shrinking over and over). Each type of bubble delivers a different sizzle.
The perfect pop
Bubble dynamics is also studied in other areas of food technology, such as soft drinks and champagne.
Beyond the physics behind the chopstick trick, these scientists are using this sizzling research to develop new technology to measure indoor air pollution with sound sensors, to improve fire safety when cooking. Another possible application is in robot-controlled cooking.
“Maybe that can actually help the robot decide when to flip burger patties once they are done,” says team member Rafsan Rabbi from Utah State University in the USA.
And if you’ll excuse me now, I believe I’m needed in the kitchen…
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