Watch a Physicist Explain How to Make ‘Bulletproof Custard’

Cornstarch plus water makes a weird sort of goo.

Kate Lunau

Kate Lunau

Cornstarch and Water Bonding - Cool Science Experiment | Mocomi Kids GIF: MocomiKids/YouTube

Have you ever mixed cornstarch and water? They make a bizarre type of goo. When combined at the right ratio, the mixture can flow like water—but when you press it with your finger, it feels solid, and might even be stiff enough to stand on. "It's an unusual suspension. The fluid is quite runny, but stiffens quickly if you try to stir it," explained physicist Michael Cates, the Lucasian Professor of Mathematics at the University of Cambridge, when I recently asked him about it.

On Wednesday at 7 p.m. Eastern time, you can watch Cates speaking live from The Perimeter Institute for Theoretical Physics in Waterloo, Ontario about soft matter physics. His lecture is colourfully called "Bulletproof Custard: Fluids That Stop Flowing When You Push Them Too Hard." (Cates told me he'll be bringing some cornstarch to demonstrate).

Image: Perimeter Institute for Theoretical Physics

Beyond just being an interesting intellectual puzzle, understanding Non-Newtonian Fluids—cornstarch and water is just one example—has all kinds of applications, from making better batteries to bulletproof vests, Cates said.

Read More: Watch a Quantum Computing Expert Describe How the World's About to Change

Cates' talk will be livestreamed on Motherboard, and if you have any questions for him, you can ask them on Perimeter's Facebook page, or on Twitter with the hashtag #piLIVE.

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