Mixing corn starch and water in suitable quantities produces a slurry that is liquid when stirred gradually however solidifies when you punch it– a compound colorfully called “oobleck.” (The name originates from a 1949 Dr. Seuss kids’s book, Bartholomew and the Oobleck) High-speed imaging and force measurements have actually exposed another unexpected residential or commercial property of oobleck drops striking a flat surface area, according to a brand-new paper released in the journal Physical Review Letters.

As formerly reported, in a perfect fluid, viscosity mostly depends upon temperature level and pressure: Water will continue to stream no matter other forces acting upon it, such as stirring or blending. In a non-Newtonian fluid, the viscosity modifications in action to a used pressure or shearing force, therefore straddling the limit in between liquid and strong habits. Stirring a cup of water produces a shearing force, and the water shears to vacate the method. The viscosity stays the same. For non-Newtonian fluids like oobleck, the viscosity modifications when a shearing force is used.

Catsup, for example, is a shear-thickening non-Newtonian fluid, which is one factor smacking the bottom of the bottle does not make the catsup come out any much faster; the application of force increases the viscosity. Yogurt, gravy, mud, pudding, and thickened pie fillings are other examples. Therefore is oobleck.

The underlying physics concepts of this basic compound are remarkably nuanced and intricate, and therefore interesting to researchers. Back in 2023, molecular engineers at the University of Chicago utilized thick suspensions of piezoelectric nanoparticles to determine what is taking place at the molecular level when oobleck shifts from liquid to strong habits.