Why is water so interesting? Featuring Olympic Gold Medalist Misty Hyman

MistyandCathy

Misty (left) and me getting ready to swim

In this two part series, I partner with my friend, Olympic Gold Medalist Misty Hyman, winner of the women’s 200 meter butterfly in the 2000 Australian games.  Misty currently coaches private lessons, leads swim clinics, and gives motivational speeches around the world.  Misty was also recently named the senior assistant coach for the Arizona State University swim team. In her spare time, Misty extends her passion for swimming into the community as a spokesperson for FitPHX and encouraging everyone to learn how to swim.

I met Misty five years ago in Valley Leadership as members of Class 32 (Best Class Ever!!) We became fast friends, even though you may not expect a scientist and a swimmer to have much in common.  To be honest, I’m not much of a swimmer, though I do love my pool and my technique improves every lesson I take with Misty.  Misty, on the other hand, is quite a scientist. Part of her swimming success came from a careful, scientific analysis of every aspect of her stroke. As we were talking one evening, we starting thinking about what we could discuss together on my blog.  What cool things in science would also be interesting to a swimmer? My first thought – WATER!

I remember the first time I really learned about water was in my freshman year of college in my intro to chemistry class. I was amazed that an entire chapter was devoted to the physical properties of water.  I knew that water was incredibly common: 71% of the planet is covered in water and humans are 65% water.  There are 100,000,000,000,000,000,000,000,000,000,000 molecules of water in an Olympic-sized swimming pool.  So what makes this incredibly common, important and useful substance so freaking cool and worth devoting an entire textbook chapter to?

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By OpenStax College [CC BY 3.0 ], via Wikimedia Commons

Lets start with the molecular structure. Water is made up of one oxygen (O) and two hydrogen (H) molecules, which is why the abbreviation for water is H2O (two Hs and one O).  The oxygen is connected to each of the hydrogens by covalent (permanent) bonds. Because of the way that the electrons within the oxygen and hydrogen atoms are distributed, the oxygen is slightly more positively charged and the hydrogens are slightly negatively charged.  This essentially makes water a weak magnet.  In chemistry, we call that “polar“. This polarity is the reason that water has so many unique properties, but I’m only going to talk about one that directly relate to swimming: surface tension. To learn more about water polarity, check out this fabulous TedEd talk.

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A great example of surface tension thanks to Pixabay

Surface tension is best described by examples:  filling a glass of water over the top, rain beading on your windshield, or bugs walking on the water of the pool.  The water doesn’t spill out of the glass, the rain doesn’t turn in sheets and the bugs don’t fall under the water and die because of surface tension. More accurately, these things happen because the polar (aka slightly magnetic) water molecules are attracted to one another and stay together.  Or to be even more scientific –  the water inside the glass or raindrop or pool is surrounded by other water molecules that can move around each other.The water molecules at the top of the water glass or pool or raindrop don’t have water molecules above them, so they are pulled inwards toward the other water,  creating surface tension.

Interestingly, surface tension directly relates to swimming.  Just take a look at this amazing photo of the effects of surface tension on the 2012 Olympic 200 meter backstroke winner Tyler Clary.  He eventually does leave the water – but he will need to use energy and force to break the surface tension at the top of the water.  This is why swimmers can swim faster underwater than on the top of the water – they aren’t fighting surface tension (plus there are other physics “things” in play like less less drag and less energy wasted with splashing underwater).

Misty’s Message: Although she would LOVE to encourage everyone to just stay underwater, that’s not realistic because we don’t have gills. However, most kinds of tension – including “surface tension” – should be avoided at all costs especially while swimming. Instead of focusing on the reality that you have to break the surface tension in order to breathe, focus on reducing drag because “not being streamlined – that’s a drag.”

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