Flushing an age-old myth

Friday, 18 November 2016

Tomorrow (November 19) is World Toilet Day. Despite spending approximately 92 days on the throne over the course of our lives, many of us still don’t know if the Simpson’s were right…does water spin in different directions in opposing hemispheres, or is that just loo-dicrous?

Toilet flushing

“What is known as ‘the Coriolis force’ is thought to cause fluids to flow in different directions in the northern and southern hemisphere.

“This force is due to the rotation of the earth causing larger eastward velocity along the equator than anywhere north or south of it,” said Dr David Boutelier, University of Newcastle (UON) Senior Lecturer in Earth Sciences.

Applied to Earth's rotating sphere, the Coriolis effect accounts in part for why hurricanes and cyclones rotate the way they do - storms rotate counter-clockwise in the Northern Hemisphere and clockwise in the Southern.

So could the Coriolis force control the commode’s current?

“It does control how the atmosphere circulates because large distances are considered. However, in a toilet or bathtub, the fluid everywhere in the conduit is basically submitted to the same force associated with the rotation of the earth, and therefore Coriolis actually has little to no effect.

“How the fluid spins is likely due to other effects such has how level the bathtub is,” Dr Boutelier explained.

So it seems that we’ve been given a bum steer all this time.

Toilet humour aside, World Toilet Day aims to increase awareness of global sanitation issues. So when making your next comfort stop, spare a thought for the 2.4 billion struggling to stay well and work their way to a better future – all for the want of a toilet. Find out more: http://www.worldtoiletday.info/.


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