They don’t look much, but these little black balls harness the power of bright light to zip across the surface of water—pulling up to 150 times their own weight in the process.
New Scientist reports that these little dots have been developed by researchers from the Osaka Institute of Technology in Japan. While you might think that the laser creates a force that pushes the spheres, the mechanism here is in fact chemical, not optical.
The laser light causes the balls to shed a little of a substance called polypyrrole that coats their surface. When released, the chemical decreases the surface tension of the water on one side of the sphere, creating a force imbalance that causes the blob to move. The results are published in Advanced Functional Materials.
When used to propel a rudimentary boat, the balls were able to push along 0.05 ounces—despite weighing just 0.0003 ounces themselves. That means they can haul over 150 times their own weight. Not bad for a tiny black ball.
It’s not the only diminutive laser-powered craft to be described in recent days. Yesterday, Stephen Hawking announced his plans to build a tiny interstellar starship that would be remotely powered by laser light.