If you've ever put a flat bag of kernels into the microwave and pulled out a full bag of fluffy popcorn two minutes later, you've witnessed a fascinating bit of food chemistry at work. Now, IEEE Spectrum reports that scientists are looking into applying the unique properties of popcorn to robotics.
For their study, presented at this year's IEEE International Conference on Robotics and Automation, Cornell scientists stuffed the movable parts of a robot (a.k.a. the actuators) with unpopped kernels of corn. Usually actuators are powered by air, hydraulics, or electric currents, but as the researchers found, popcorn works as a cheap single-use alternative.
When heat is applied to popcorn kernels, the water trapped inside them turns to steam, creating enough pressure to peel back the tough exterior and release the starchy endosperm. A sudden drop in pressure causes the endosperm to quickly expand, while the cool outside air solidifies it.
The results can be dramatic: When popping extra small white kernels, the cheapest popcorn tested, researchers saw them expand to 15.7 times their original size. Inside a soft robot, this amounts to building interior pressure that moves the actuator one way or another.
A similar effect can be achieved using air, and unlike popcorn, air can be pumped more than once. But popcorn does offer some big advantages: Using popcorn and heat is cheaper than building air pumps, plus popcorn is biodegradable. For that reason, the researchers present it as an option for robots that are designed to be used once and decompose in the environments they're left in.
You can get an idea of how a popcorn-powered robot works in the video below.
[h/t IEEE Spectrum]