Saturday, July 12, 2014

Clockwise v counterclockwise

We were posed a very interesting question in class today.  Which way does the water go down the drain in the women's restroom closest to our class today.  After observing the water go down the sink drain twice, I observed that the water descended the drain clockwise.

Then we were asked if we thought that the water goes down in the same direction in the southern hemisphere to which I answered yes.  I simply didn't see why it would go down in a different direction south of the equator.  However, after some research, I learned that there is actually no correlation as to which direction the water flows down the drain to the hemisphere.

According to the Huffington Post, there are many other components that determine which direction the water descends.  According to  Dr. Paul Doherty, senior scientist at the Exploratorium in San Francisco "water can swirl either way anywhere on earth--and that which way it swirls is effectively random".   (

In addition, I learned about the Coriolis effect which is what many people base their theory of water flowing clockwise in the northern hemisphere and counterclockwise in the southern hemisphere.  In's "everyday Mysteries section" an article reads, "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. Don’t believe them! The Coriolis force is simply too weak to affect such small bodies of water". So why is it that many believe that hemisphere's determine the direction of the water flow?  Because hurricanes and tornados' cyclical flows follow a counterclockwise flow in the southern hemisphere and a clockwise flow in the northern hemisphere.

Lastly, I saw an amazing video on Youtube which proves that there are so many different elements that determine the flow of water: none having to do with the hemisphere.  For example, filling the sink from the left side of the sink determines which way the water flows.

Therefore, there is absolutely no correlation between which hemisphere the drain is located and the flow of the water going down the drain.

Stephanie Ruiz

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