I wanted to share this great youtube video demonstrating a classic kitchen-science non-newtonian fluid: cornstarch and water. The creator puts this mixture on a cookie plate and presses the plate against a subwoofer. The result is pretty great!
A little background on newtonian fluids
In a newtonian fluid the shear rate (rate of flow) is directly proportional to the shear force (how hard you push on the liquid), and the constant of proportionality is the viscosity. So if you double the shear force, you double the shear rate. In a non-newtonian fluid that’s not true, and it can be untrue in different ways. The most straightforward comment is that you can get a non newtonian fluid if the viscosity is not constant. In the case of cornstarch and water you have a fluid where the harder you shear it the more viscous it gets. Compare this to water where the harder you shear it the faster it flows.
Wikipedia has a decent article on non newtonian fluids that you could check out.
Do you know why this works?