Slashdot Mirror
Make A Hole - And Sustain It Indefinitely
Mick Ohrberg writes "Florian Merkt, Robert Deegan, and Erin Rericha, all at the University of Texas, have shown that a hole created in a water and cornstarch mixture with a puff of air can be persistent if the mixture is shaken at about 120Hz with acceleration being in the 12g-25g range. The physics behind the phenomenon has not yet been explained."
It seems that the world of physics as it relates to lots of macro sized particles interacting isn't very well explored.
I remember reading an article years ago, about research into mixed nuts. Basically they wanted to find out why the brazil nuts always tended to come to the top. It turns out it's a semi-complex interaction, when the can is shaken vertically, the nuts closer to the walls are pulled down due to the friction and they fall into the gap created at the bottom of the can, creating a sort of convection current. The larger brazils had less contact area with the wall and were not as likely to be pulled back down IIRC.
It's just kinda funny that we understand all kinds of interactions down on the atomic level, but are still researching basic things like the way mixed nuts or raisin bran sort and settle.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
It's quite simple, really. The glass container in which the corn starch is stored resonates perfectly at 120Hz. Had the researchers used a difference thickness, weight or purity of glass, the required frequency would be different, though far less stable. What they have done, in effect, is open a very small gateway into a sub-level dimension. It is fortunate that they did not accelerate the container to a rate generating more force, which would have caused the hole to open larger; they might have inadvertently unleashed one of these.
Firstly, i would guess that the inside of this structure is PERFECTLY round. I mean, so 100% perfect, something which we cannot create atm. Which will then be used some how. (like creating ROUND m&ms?). Still, no one know what it all means?
- http://www.milkme.co.uk
scale the whole project up, and easy access to sunken boats?
treasure is always a good incentive...
I downloaded the removed video when the site was on Fark this week. You can get it off my server here (3.8 meg wmv).
Your reality is lies and balderdash and I'm delighted to say that I have no grasp of it whatsoever. - Baron Munchausen
Similar to the 'liquid body armor' reported on Slashdot a while back, cornstarch + water is a "sheer-thickening" fluid, or a fluid that increases its viscosity when it experiences sheer (or tangential force).
Perhaps the interaction between the cornstarch/water and the vibrations cause the cornstarch/water to increase its viscosity and "hold" up the walls of the hole.
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How much cornstarch do you need for the Red Sea anyway?
Given that cornstarch and water is a shear-thickening fluid, and the vibration (at 15-25g no less) is certainly a shear force, this phenomenon is almost certainly due to the vibration causing the cornstarch and water to gain viscosity. This wouldn't necessarily give you a stable hole, though, so it's probably also helped by the cohesive forces in the fluid and some other effects, too.
I would guess that it's not that the scientists don't know why this is happening, just that their models aren't accurate/precise enough to predict it. Or maybe they left out some effect or force that is normally negligible in the models, but suddenly becomes important in this situation.
Doesn't ACME have a patent on portable holes? I think these guys may want to check with their lawyers...
How'd they come across this?
Hey Joe... Let's take some water... and add some cornstarch.. and then. hmm... apply a really high frequency, and then puff some air down into it.
Ya know Bob, that's a really great idea.
-Jesse
Nothing says "unprofessional job" like wrinkles in your duct tape.