![]() ![]() Ketchup, for instance, is a non-Newtonian fluid, which is one reason smacking the bottom of the bottle doesn't make the ketchup come out any faster in fact, it slows it down, because the application of force increases the viscosity. ![]() But non-Newtonian fluids like oobleck? Their viscosity changes when a shearing force is applied. Physicists like to call this a "shearing force": stirring a cup of water produces a shearing force, and the water shears to move out of the way. In a non-Newtonian fluid, the viscosity changes in response to an applied strain or shearing force, thereby straddling the boundary between liquid and solid behavior. In Newton's ideal fluid, the viscosity is largely dependent on temperature and pressure: water will continue to flow - i.e., act like water - regardless of other forces acting upon it, such as being stirred or mixed. But the world is not an ideal place, and not all liquids behave like Newton's ideal liquid. ![]() ![]() Anyone who's ever stuck their arm out of the window of a moving car can attest that there is more air resistance the faster the car is moving (air is technically a fluid). The faster one layer slides over another, the more resistance there is, and the slower one layer slides over another, the less resistance there is. The friction arises because a flowing liquid is essentially a series of layers sliding past one another. One of those properties is viscosity, loosely defined as how much friction/resistance there is to flow in a given substance. Isaac Newton first delineated the properties of what he deemed an "ideal liquid," of which water is the best example. And one of the most common at-home science experiments you can do involves water and cornstarch mixed in proper proportions, to give you an instant (almost) non-Newtonian fluid. Oobleck is a favorite substance of mine, because it just can't decide whether it wants to be a solid or a liquid - it swings both ways! It's worth pointing out that the Brainiacs didn't use custard made from scratch with eggs and milk and sugar - they used custard powder, which is mostly comprised of cornstarch. The stuff was called " oobleck," and as often happens with magic spells, it turned out to be more troublesome than entertaining, gumming up the entire kingdom until the creatively pragmatic Bartholomew figures out how to save the day. King Derwin is a bit of a dunderhead who decides he's bored with plain old water-based rain and show, and orders the casting of a magic spell that causes a green sticky substance to rain down from the sky. Seuss, specifically, a tale called Bartholomew and the Oobleck.īartholomew is a royal page in the Kingdom of Didd. So what gives? Well, as the Brainiacs explain in the video, it's an example of a non-Newtonian fluid - or, as I like to think of it, "oobleck." That's a nod to Dr. It's impossible to walk on water - unless one happens to be Jesus, who "cheated" by being of divine origin -but it's entirely possible to walk across custard. I was reminded of the Brainiac series this morning, when one of their YouTube clips popped up in my feeds: host Richard Hammond (who now co-hosts the hugely popular Top Gear) coaxes his co-host Jon Tickle into demonstrating an experiment. The British also do a mighty fine job on the science end of things, whether it be serious, Attenborough-narrated fare like Frozen Planet, or something more playfully irreverent and silly, like Brainiac: Science Abuse, which ran for nearly five years (2003-2008). Not only does Jen-Luc Piquant adore the BBC's modern Sherlock reboot, she's also a diehard fan of all those Inspector Morse mysteries ("Oh, for god's sake, Lewis!") and the weirdly oddball Blackadder series ("I have a cunning plan!"). Man, those Brits have some awesome TV programming. ![]()
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