Originally posted by mikhael
You can make a version of this stuff with cornstarch and water.
The substance is often referred to as Oobleck (from the Dr. Seuss story, "Bartholomew and the Oobleck").
Basically what happens with a properly proportioned combination of cornstarch and water is that, at low pressures it flows like a liquid, but at high pressures the water molecules are forced out of suspension and the starch molecules lock together.
Fun stuff-- oozes everywhere, but you can hit the surface of it with a hammer and it won't splash. Yes, it'll even crack if the mix is just right. You can even pick some up and roll it into a ball... which collapses the moment you stop pressing on it.
