NextBillion - An Initiative of the William Davidson Institute at the University of Michigan

Thursday, January 12, 2017

Centrifuges, which separate materials in fluids by spinning them at great speed, are found in medical labs worldwide. But a good one could run you a couple grand and, of course, requires electricity — neither of which are things you’re likely to find in a rural clinic in an impoverished country. Stanford researchers have created an alternative that costs just a few cents and runs without a charge, based on a children’s toy with surprising qualities.

It’s a whirligig, and it’s a simple construction: a small disc, probably a button, through which you thread a piece of string through twice. By pulling on the threads carefully, you can make the button spin quite quickly. You may very well have made one as a child — as Saad Bhamla, one of the creators of what they call the Paperfuge, did.

“This is a toy that I used to play with as a kid,” he says in a video produced by the university. “The puzzle was that I didn’t know how fast it would spin. So I got intrigued and I set this up on a high-speed camera — and I couldn’t believe my eyes.”