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Stumper #50.
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[i.e. your Knowledge Quotient]

Thick Water

All around the world water moves in oceans, seas, lakes, rivers, ponds and pools. It ebbs and flows, rushes, trickles and stagnates. Poetically it can be moody, wild or peaceful; for some of us it is calming and for some an irresistible challenge.

There are several well-known challenges for long distance swimmers the distance between Alcatraz and San Francisco in California, and the narrower part of the English Channel for example. For speed-swimmers the challenge is less one of endurance than of accomplishing bursts of speed over short distances.

In any case there are external, physical forces to be dealt with. The human body has a similar density to water so staying afloat is relatively easy. Wearing tight fitting, smooth swimwear helps to overcome "frictional drag". Having a narrow torso helps to overcome "form drag".   Moving purposefully forward requires having muscular strength.

A swimmer must generally use both arms and legs to move forward and the most efficient swimming stroke is the crawl, also known as the trudgen, over arm crawl, Australian crawl, front crawl or freestyle. Using this stroke in competition, swimmers can reach speeds of about 5 miles per hour over distances of 25 or 50 yards.

Some curious minds, including that of Isaac Newton, have wondered if a swimmer could swim as fast in a fluid more viscous than water. Newton said the viscosity would slow the swimmer down while his contemporary, Christiaan Huygens, thought it would not.

This question as related to human swimmers was not put to the test until a few years ago when Edward Cussler of the University of Minnesota had a swimming pool filled with a solution of guar gum, an edible thickening agent. This resulted in a swimming environment twice as viscous as water. Sixteen swimmers tested their strokes in this syrupy pool as well as in a regular pool, which leads us to our first stumper question.

Stumper Questions:

1. Do humans swim slower in syrup than in water?

2. Which one of Newton's three laws of motion explains why some people can swim faster than others?


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