The Physics of Cornstarch

Cornstarch, or in general, fine granular materials have tons of cool physical properties. For example, while cooking, we use cornstarch as a thickening agent. Its little granules can trap water molecules, making delicious gravies with it.
But, also we can create a non-newtonian liquid, that is, where its viscosite changes if you let if flow or push it. With some water and cornstarch, this granular material has some weird properties. It flows like a liquid, but if you hit it really hard it feels as solid as a block.
The guys upstair made this really cool video of other properties of this non-newtonian liquid, check it out. They shake the liquid at high accelerations, where structures form. Some are stable, like holes in the liquid, others are dynamical, like fingers that grow out of it. Pretty cool, and a bit gross.