slippery water

MaryW commented on the word slippery water

Though best known as a thickener, guar means something else entirely to firefighters, pipeline operators, or the designers of ship hulls and torpedoes. In minute quantities, it has the ability to create "slippery water," a phenomenon that greatly reduces drag. One physicist described molecules of guar gum (and similar plymers) as double yo-yos, coiling and uncoiling in such a way that they prevent turbulent liquids from adhering to adjacent surfaces. The physics are still poorly understood, but in practice this effect speeds the movement of fluids through hoses and pipes. The US Navy has also studied it as a way to increase hull efficiency and reduce the noise of its ships, submarines, and torpedoes.

Thor Hanson, The Triumph of Seeds: How Grains, Nuts, Kernels, Pulses, & Pips Conquered the Plant Kingdom and Shaped Human History (New York: Basic Books, 2015), endnote accompanying ch. 3, p. 50.

January 30, 2016