The Physics of Peeing in a Urinal

Don’t want urine on your pants? Of course not; working out an ideal standing technique to minimize splash-back has been mankind’s loftiest goal since the dawn of the urinal. Now, some physicists from Brigham Young University think they’ve sorted it out.

According to the whizz-kids (they coined it, not me), sitting is actually the best way to avoid splash-back, as the contact point is much closer. However, scientifically speaking, sitting down to pee is tedious, unless there’s a magazine article you really want to read, so the key is to stand as close to the urinal as possible. The problem is something called Plateau-Rayleigh—that is, when your pee stream breaks into separate drops before striking the porcelain. Each drop causes it’s own splash-back, and a closer contact point minimizes this. Also, you want a downward angle, to hit a vertical target instead of a horizontal one, and to not stand immediately next to your urinal neighbour if you can’t help it.

Need more help? Well, the whizz-kids made a video. It’s not real pee, just coloured water. Because we need to draw the line somewhere.

[youtube width=”640″]http://www.youtube.com/watch?v=UgOx7zPtsaM[/youtube]


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