Cornstarch & Water - Explained by Physicists

Heinrich Jaeger, William J. Friedman and Alicia Townsend Professor in Physics, and Scott Waitukaitis, a graduate student in the Physics department, have published a report in the July 12 issue of Nature on the process of impact-activated solidification that occurs when compressive forces are applied to fluid-grain suspensions. The two researchers conduct experiments with a mixture of cornstarch and water that is classified as a non-Newtonian liquid. Their work examines the strange behavior of the cornstarch-water liquid, which instantly changes into a solid within the area of impact. The behavior of non-Newtonian liquids has puzzled scientists for decades, and Waitukaitis and Jaeger's report sheds new light on this longstanding problem in suspension science.

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  Science & Technology

[johnb003]

Based on the title, I was expecting to learn about the physics behind it, instead of hear a physicist say, "it's a liquid, but when you hit it really hard it turns into a sold".

Cool footage none the less.

[Scott Waitukaitis]

It depends on the speed! We're currently working on experiments to try to figure out how this speed/pressure dependence works!

[Maurizio Antonio Carlucci Zambrano]

Hello, I'm making a school project about this topic. Can I make you a few questions about the experiment?

[Seth Nguyen]

Start at 2:18 and listen to that sound that has to hurt!

[Arthur Hemming]

Interesting. So there may be a way to change between solid/liquid states by changing the pressure of the solution? I guess what I'm asking is would it be possible to create "structures" that can also be turned into a liquid or solid at will?

[Scott Waitukaitis]

Check out the article at Nature.com for the full physics details :)

[Arthur Hemming]

The grains of cornstarch grouping together to form a "temporary column solid" seems fairly commonsense. Although I wonder, if pressure is continuously applied at the same speed, does the solution still remain solid?

[lallu316]

I'm gonna buy cornstarch on the way home tonight!

[MisterOh1]

haha what a fuckin nerd he hurt his fist