Ever heard of a non-Newtonian fluid? Yes, you have. You just didn’t realize it. Wikipedia says “A non-Newtonian fluid is a fluid whose flow properties differ in any way from those of Newtonian fluids. Most commonly the viscosity of non-Newtonian fluids is not independent of shear rate or shear rate history. However, there are some non-Newtonian fluids with shear-independent viscosity, that nonetheless exhibit normal stress-differences or other non-Newtonian behaviour”.

Um, sure. Some examples?

Oobleck is not just a made-up substance from the Dr Seuss story Bartholomew and the Oobleck. It is an odd material that variously behaves as a liquid or a solid depending on how it’s handled.

Flubber is not only a fictitious bouncy substance in the movie The Absent-Minded Professor, it is a real substance classified as a non-Newtonian fluid. It flows under low pressure but breaks under high pressure.

A more complete list of non-Newtonian fluids would include ketchup, custard, toothpaste, paint, blood, and shampoo.