NEW ORLEANS, LOUISIANA—No matter how slowly and carefully you peel an orange, you’re likely to get juice on your hands. To find out why, researchers used high-speed video to capture in slow motion what happens when the rinds of lemons, and navel and Valencia oranges are squeezed or bent. They then applied engineering tools to measure the pressure that built up inside the fluid-filled oil glands that sit just under the skin of citrus fruits. The glands vary from spherical to almost cylindrical, building up enough pressure inside before rupturing that they can shoot droplets out at 10.5 meters per second (faster than an insect can fly or a raindrop can fall), the scientists found. And the droplets go from standing still to top speed in less than a millimeter, being subjected to acceleration 1000 times that experienced by astronauts taking off in space, the team reported here today at the annual meeting of the Society for Integrative and Comparative Biology. The researchers are still trying to figure out exactly how this speed is so quickly achieved and why the oil quickly breaks into small droplets, information that could help them design an emergency asthma inhaler filled with exploding pockets of medicine, they note.
Source: Science Mag