Podcast Transcript: How can we improve engines, inhalers, and fire extinguishers? Maybe by copying a beetle. The bombardier beetle’s name might scare off predators if they knew it. To protect itself, the beetle shoots a spray of hot, toxic venom. The spray can travel nearly eight inches, about 2000 times the length of the insect’s combustion chamber.
Scientists from Leeds University and from Swedish Biomimetics 3000 reported on these propellant abilities in the April issue of Physics World. Hydroquinone and hydrogen peroxide build up in the insect’s abdomen. When the beetle needs protection, the chemicals flood the combustion chamber. In the presence of a catalyst, the chemicals create a toxin, along with other compounds and water. The reaction heats to near boiling. When the pressure is high enough, a membrane at the other end of the combustion chamber opens, and the mist and liquid fires. The pressure drops and the combustible chemicals quickly refill the chamber, leading to a series of bursts. Scientists modeled and replicated this system using hot water instead of venom. They say it could offer huge power and environmental benefits over current high-performance spray technologies.