I can’t remember whose blog got me here but this experiment using non-Newtonian fluid might freak me out a little bit less if I understood what it meant for fluid to be non-Newtonian.
I read the wiki entry on non-Newtonian fluids, and while I recognized all those words as being English, they made no sense whatever when strung together that way. My brain has thus been rendered useless, and I fail to see why I’m even at work now, since I’ll no doubt be unproductive all day.
The video, however, is pretty darn cool.
I can’t watch the video at work, though I can, thankfully, still read your blog. Think of it like this… If you’re dealing with a fluid that is actually a suspension, or some other sort of heterogenous mixture, like blood or semen, the way it reacts to certain kinds of pressure won’t always make basic physical sense to an untrained observer. This is particularly true (and plainly observable to the vast majority of gays,) with semen. After a pause for reflection, does this make you feel any better?
A non-Newtonian fluid is, in most cases, a suspension of solid particles in liquid.
When you move it slowly, it behaves like a liquid – it pours, oozes, etc. When you try to move it quickly, the pressure causes all the solid particles jam up against each other, and it starts to behave like a solid. When the pressure is relieved, the fluid starts to behave like a liquid again.
Literally, it’s cornstarch and water, although the ratios are a little narrow – 2 parts cornstarch to 1 part water is close. Mix some up in the kitchen and play with it. It will shatter if you hit it with a hammer, and then the shattered pieces will regain their liquid behavior and melt right back together.
You’re probably familiar with many non-Newtonian fluids. Ketchup for instance is a non-Newtonian fluid, which is why smacking the bottle makes it flow out easier. Toothpaste is another non-Newtonian fluid.
There are two types of non-Newtonian fluids, shear thickening and shear thinning. For shear thickening fluids, basically, the harder you press on them (shear force), the thicker they become. Cornstarch and water is a shear thickening non-Newtonian fluid too. Shear thinning fluids become more liquid-like under pressure, which is why ketchup is thick, but pours more easily when the bottle is smacked, or squeezed from a squeezable container.
Silly Putty and Slime are both non-Newtonian fluids too, both are shear-thickening liquids. Go to the Dollar Store and buy some (but don’t get them on the carpet, young man!) If you pull either of them slowly, they make long strands of goo. But, if you pull a piece of it apart quickly, it “breaks” in a clean line — shear thickening at work.
(I first learned about non-Newtonian fluids from Mr. Wizard.)
Ha ha, this is “oobleck” from Dr. Seuss’ book, “Bartholomew and the Oobleck”, created for the king when he was bored, if I remember (it was green)…. We’ve made it in blue in kindergarten and science class and Cub Scouts for years. But I’ve never seen it do really freaky stuff like this…
If you mix up a big enough batch, you can walk on a cornstarch and water mixture, provided you stomp. Stand still and you sink.
Between this and all of the videos of fractals I’ve been watching for my presentation in my stoner math class next week, I’m starting to understand (though still not quite approve of) the people in high school who wore “Physics is Phun” t-shirts.
That looked like something out of a sci-fi/horror flick, like the alien in John Carpenter’s remake of “The Thing.”
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