A non-newtonian fluid under stress reacts as a solid. In this case they filled a pool with a mix of cornstarch and water made on a concrete mixer truck. It becomes a non-newtonian fluid. Update: Liquid Armor is one of this fluid's applications.

Here's another cornstarch and water solution, which becomes a non-newtonian fluid. A Non-Newtonian fluid, has properties that cannot be described by classical fluids. In this video clip, the non-newtonian fluid is a mixture of corn starch and water.

This is a followup of Pool with non newtonian fluid. As seen there non-newtonian fluids can have different properties (fluid/liquid) depending on the stress. Here is an up-to-date application for the military: Liquid Armor. Enjoy! Liquid Armor - video powered by Metacafe