More Solid When Disturbed

I learned something today about non-Newtonian liquids -- cornstarch and water!! Two different examples!!

Walking on liquid!!

Speaker activated liquid!!

An interesting collection of these on YouTube!!

What's the principle behind this?

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Alex Boese Alex is the creator and curator of the Museum of Hoaxes. He's also the author of various weird, non-fiction, science-themed books such as Elephants on Acid and Psychedelic Apes. Paul Di Filippo Paul has been paid to put weird ideas into fictional form for over forty years, in his career as a noted science fiction writer. Contact Us

Posted By: gdanea - Thu Feb 04, 2010
Category: Science

Comments

What's the principle behind this? It's MAGIC! :wow:

Posted by Expat47 in Athens, Greece on 02/05/10 at 12:02 AM

be that as it may john, it still looks like magic! :wow:

Posted by Patty in Ohio, USA on 02/05/10 at 07:25 AM

they were messing about with this in an episode of the big bang theory. very cool.

Posted by Nethie on 02/05/10 at 12:10 PM

custard? "today we have a delicious experiment..."

Posted by Patty in Ohio, USA on 02/06/10 at 10:55 AM

Part of the reason for this behaviour is that water becomes less viscous under pressure, most liquids become more so. This means that when compressed the water is more quickly able to run away from the point of contact and can sometimes leave the solid particles with too little liquid suspension to flow easily. If you make a similar mix of cornstarch and cooking oil, you don't get this effect, just a sticky, but Newtonian, mess.

Posted by Dumbfounded on 02/08/10 at 09:53 AM

Thixotropy --

John Armstrong and Dumbfounded have the concept right.

http://www.questia.com/read/117012268?title=Colloid

http://en.wikipedia.org/wiki/Thixotropy

Regards,

Professor Music

Posted by Professor Music on 02/09/10 at 12:28 AM

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