Reflections: Which way does the water drain?
Which way does the water drain?
By William L. Bulla
I recently overheard some friends discussing the way water drained above and below the equator. When they asked me, I was unable to give them an answer.
In which direction does water swirl down the drain north of the equator? What about south of the equator? Over the years, I have heard people say that it flows in different directions. I have heard that water swirls down the drain counter-clockwise north of the equator and clockwise south of the equator. Now many people refute that fact. What is the truth? Does water go down the drain counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere?
The idea that toilets and bathtubs drain differently in the Northern and Southern Hemispheres has been popularized by several television programs, including The "Simpsons" episode "Bart vs. Australia" and an episode of "The X-Files." Several science broadcasts and publications, including at least one college-level physics textbook, have also stated this. However, in researching this topic, most references state it is a myth that water naturally swirls a different direction down a toilet bowl positioned north or south of the equator. It all depends upon how the water was introduced and the geometric structure of the drain.
One can find both counterclockwise and clockwise flowing drains in both hemispheres. Some people would like you to believe that the Coriolis force affects the flow of water down the drain in sinks, bathtubs, or toilet bowls. The effect, known as Coriolis Effect, applies to larger systems like the weather. The Coriolis force is simply too weak to affect such small bodies of water.
The Coriolis force was named after the French scientist, Gaspard Gustav de Coriolis, who first described this force in a 1835 study. The Coriolis force is caused by the earth's rotation. The Coriolis Effect is the observed curved path of moving objects relative to the surface of the Earth. Hurricanes are good visual examples. Hurricane winds moves counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere because of the rotation of the Earth. The Coriolis force assists in setting the circulation of a hurricane into motion by producing a rightward (clockwise) deflection that sets up a cyclonic (counterclockwise) circulation around the hurricane low pressure.
According to "Science World", at the equator, the Coriolis force is too weak to operate on the moving air. This means that weather phenomena such as hurricanes are not observed at the equator, although they have been observed at 5 degrees above the equator. In fact, the Coriolis force pulls hurricanes away from the equator.
I don't believe I really care which direction the drains in my house flow. My main concern is to keep them open and flowing.
William L. Bulla is a freelance writer residing in Washington County.