Oobleck - It's not just for Dr. Seuss Anymore

Oobleck is actually more than just a made-up name for the stuff in the Dr. Seuss book, it's the name now applied to a whole class of fluids which display what is called "shear thickening." 

That just means that when they have a sudden force applied, include of splashing to the side, the perversely get thicker and harder.  It's the topic of this month's feature article in Physics Today and admittedly had nothing to do with astronomy.  But hey, the featured YouTube video lets you skip through all the technical parts of the article and see what the effect really is (scroll to the bottom of the Physics Today article).

Apart from making for funny videos, what is such an effect good for?  Well, buried in the middle of the article is a note about the potential for soft armor.  A test batch of Kevlar formulated with one type of polymer colloids boosted Kevlars strenght by 50%.  Another formulated with silica colloics boosted it by 150%; that means the test "bullet," a quarter-inch round steel ball had to travel 100 meters/second to penetrate the regular material now had to travel 250 meters/second.There are some images and video of the tests at the University of Delaware's Shear Thickening Fluid lab.

I do have to say that silly game show videos aside, I wouldn't recommend filling a pool with the stuff with small children around; the consistency is like a thick quicksand and is potentially just as dangerous.  And even though you can make it from just water and starch, I'm not quite sure how to dispose of the stuff when you're all done....