Tuesday, 17 December 2013

Physicists Find the Best Way for Males to Piss

Yes... really. Four physicists at Brigham Young University have been studying the fluid dynamics of liquid in a urine-like environment. They wanted to see which method of pissing produced the minimal amount of splash back. A purely respectable scientific task!

The team at Brigham set up experiments with a nozzle which ejected colored liquid, which mimicked the penis urinating, into a tank of water and filmed the process with high speed cameras. The footage revealed how much splash back was caused by different trajectories of the colored liquid.

They surmised that the best way to piss in the toilet was to do it sitting down, this is because shorter distances between the nozzle (or penis) and surface of water cause less splash back. Through careful analysis of the liquid they realized that it ( ~15cm from ejection point) formed into droplets before impact which caused more splash back. The formation of droplets by a jet of liquid is called the Plateau-Rayleigh instability and it is a phenomenon in fluid dynamics. This image briefly conceptualizes the physics:

where tiny perturbations in the fluid follow sine or cosine  growth functions, which grow differently... this chaotic behavior causes the disruption of flow and leads to the formation of droplets which are caused by surface tension. 

So basically follow these steps to pee the most efficiently:

  1. Pee sitting down on a toilet.
  2. If (1) is too degrading pee closer to the toilet whilst standing.
  3. If (2) is true, then also aim more downwards towards the back of the toilet. 
  4. Try to avoid Rayleigh instability.
  5. When peeing against urinal, pee close to it and against the most vertical wall of urinal.
And people say science doesn't help us in our everyday lives... pfft...

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