Saturday, July 12, 2014

Solving the age old question of which way the water drains

Hello everyone, my name is Hector. I am from Boston and I love everything that has to do with history. Taking this class is a way for me to learn more about the ecosystem in Boston harbor and how it has affected the development of the area.

Today we took a field trip into the ladies bathroom at BU where we observed water drain from a sink and the direction the water drained. Of course the water drained clockwise since we are in the northern hemisphere.. but is that really why? Water drains clockwise in the Northern Hemisphere and counter clockwise in the Southern Hemisphere? This video made by Ewan McGegor and Charlie Boorman I found in YouTube obviously shows this to be true but I needed more proof than just believing what the actor that played the wise Jedi Obiwan Kenobi says.

I took to my own observations to see what I could debunk or prove.

  • Water experiment #1 at BU drained counter clockwise
  • Water experiment #2 at home kitchen sink the water drained counter clock wise
  • Water experiment #3 at home bathroom sink the water drained clockwise
  • Water experiment #4 called a friend to drain his sink, water turned counter clock wise
I had assumed that the movement of the Earth caused the water to turn with it. This made sense with because of the Coriolis effect which makes objects moving appear to shift direction when it is in fact the turn of the earth and not the object that is changing. This can be seen with long range artillery used by armed forces in many wars. Doing more digging into the subject I learned that the Coriolis effect causes hurricanes to move clockwise in the Northern hemisphere and counter clockwise in the Southern Hemisphere. 

Everything makes sense now except my results.. but the more I searched, the more articles I found saying that the Coriolis effect cannot possibly have an effect on a sink draining. I wondered if there was a factor changing my answers. Going back to the artillery pieces I thought about the rifling that is done inside the guns to increase accuracy. While this had nothing to really do with the sink and water it made me think if there might be something that changes the movement of the water in my sinks, maybe some crumbs or other objects that have a significant effect on the path of the water. I couldn't really find much in my own sinks but I decided to see how adding and removing the filters changed anything and sure enough the way the water drained changed. 

In the end the result was that the earth does not have an effect on the way water drains down a sink, it can drain in any way no matter in what hemisphere it is. The factors causing the direction are left over dirt, crumbs, and other little objects that build up over time. 







http://www.scientificamerican.com/article/can-somebody-finally-sett/

http://science.howstuffworks.com/science-vs-myth/everyday-myths/rotation-earth-toilet-baseball5.htm

https://stratus.ssec.wisc.edu/courses/gg101/coriolis/coriolis.html

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