Popcorn-Powered Robots? Get ‘Em While They’re Hot!

Say the word "popcorn," and you'll likely think of a tasty theater treat. But these little kernels are capable of doing much more than just cutting the muted tension of a John Krasinski film. They contain a deployable reservoir of force. With the addition of heat, the process of popping unleashes a Pandora’s box of energy that, if harnessed, can be put to work.

Steven Ceron, a mechanical engineer at Cornell University (and, we assume, popcorn devotee), decided to do just that in series of experiments. In May, he presented the tantalizing findings at the IEEE International Conference on Robotics and Automation: popcorn-powered robots. Now, Ceron has written up his results in a paper—and it’s caused quite the robotics ruckus.

“My first reaction was to wonder if this was a very well-researched joke,” says Adi Azulay, a design developer at Microsoft who was not involved in the research. “But they did everything in there—and achieved everything they set out to do.”

It’s understandable how all this might get overblown. The phrase “popcorn-powered robots” evokes quite the image—but before your imagination runs wild with a B-movie plot detailing hyper-intelligent humanoids spewing fiery kernels into the streets of Manhattan, keep in mind that corn-fueled functionality is still in its infancy.

The robots presented in Ceron’s paper, “Popcorn-Driven Robot Actuators,” are simple: for instance, one is a three-fingered hand that grasps a squishy ball; another supports the weight of a nine-pound kettlebell.

Actuators are components of devices or systems that convert energy into a purposeful motion, usually to accomplish a task—like a mechanism that closes and opens a valve to release steam. But actuators can go beyond machinery: Your bicep, for instance, is a kind of actuator, since it channels energy from your cells into movements like flexing.

When a popcorn kernel pops, it undergoes a striking physical transformation. The application heat super-steams pockets of water inside the teardrop-shaped nugget. Eventually, the pressure builds up to the point where it can no longer be contained by the fragile outer shell—and the starchy content explodes forth (incidentally, the “pop” you hear is actually the sound of pressurized water vapor being liberated from its corny shackles). This veritably volcanic eruption is what allows the starchy, pillowy flesh inside to pirouette out, expanding up to 15.7 times in volume. Bathed in the relatively cool surrounding air, the billows dry and resettle into puffy, crunchy clouds that pair so well with butter and salt.

Ceron and his colleagues realized that they had watched this energy go to waste for too long. In an attempt to harness the power of pop, the researchers decided to see if they could go against the grain and push the boundaries of this staple starch.

Popcorn-Driven Robotic Actuators

Watch on

In one experiment, the researchers used popcorn to power a “jamming” actuator, adding structural integrity to a loose outer shell as the kernels popped. The popcorn jammed against itself as it expanded, making the structure stiff enough to tug a hanging 100-gram weight upward. In another, the team used the popcorn purely as an energy source, placing kernels in a flexible container between two plates attached by wires. As the kernels burst open, the plates were pushed apart, tugging the wires taut and clamping a hand-like “gripper” shut beneath the contraption.

“We really hope that [this work] will motivate others to consider non-traditional materials, even something as random as popcorn,” says Ceron in an interview with Evan Ackerman of IEEE Spectrum.

The big downside to popcorn-powered robots? There’s no Benjamin Buttoning these corny explosions. Not only is this a one-time-only actuator—but once you fill a system with popped corn, you still need to clear out the rubble (though, as the paper points out, erupted kernels will dissolve in water after two weeks—which is nice if you’re operating under a very, very lax deadline).

But what popcorn lacks in sustainability, it makes up for by being light, cost-efficient and biodegradable—especially when compared to an air pump, which, though capable of recycling air through its system, would also require a relatively expensive manufacturing process that adds a lot of weight to a robotic system. In other words, perhaps popcorn may become the compostable plate of robotic dinnerware.

“We don’t always have to look for high-tech solutions,” Ceron’s supervisor Kirsten H. Petersen, who runs Cornell's Collective Embodied Intelligence Lab, argues in a press release for Cornell. “Simple robots are cheap and less prone to failures and wear.”

And, of course, popcorn is oh-so edible. One appealing application might be an ingestible device for a medical procedure—though first researchers would have to very carefully tinker with their mechanics to ensure that a series of starchy explosions wouldn’t wreak havoc in the human body. Another obstacle, as Azulay points out, is that “while popcorn is ingestible, none of the ways of popping it are.”

So while there may be kernels of knowledge to glean from this work, as usual, only time will tell if the findings are truly worth their salt.

Katherine J. Wu | | READ MORE

Katherine J. Wu is a Boston-based science journalist and Story Collider senior producer whose work has appeared in National Geographic, Undark magazine, Popular Science and more. She holds a Ph.D. in Microbiology and Immunobiology from Harvard University, and was Smithsonian magazine's 2018 AAAS Mass Media Fellow.