Can you blow smoke rings that twist into knots?
This is Sandra Tsing Loh with the Loh Down on Science.
Quite a tongue-twister, no? But University of Chicago physicists have figured out just how to do it—no tongue twisting required. Instead of using smoke in air, they're using bubbles in water.
Dustin Kleckner and William Irvine used a 3D printer to make twisted ribbons of plastic. The ribbons are wedge-shaped, like an airplane’s wings. They can be tied in a three-part loop, or linked in rings.
When dragged or jerked underwater, the loops set off tiny tornadoes, tied in knots. They also create two linked bubble rings.
Besides being fun, why make bubble knots in water?
Physicists call them "knotted vortex rings," and it turns out they're everywhere—from the surface of the sun to the middle of a storm—even in the air turbulence that shakes up planes!
The pair found that the rings come apart violently, then rejoin. Understanding why could be useful for, say, weather prediction.
But for now, it’s just cool to tie knots in water. And we're not just blowing smoke!
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This Thursday, from 2-3 p.m. (PT) on the Loh Down on Science blog, join Sandra as she chats with humorist Henry Alford about the science of laughter!
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