The curveball question: Water or syrup?

For the full feature, see “Six steps to handling the curveball question.”

Now, how about the water/syrup conundrum? In 2004 two University of Minnesota chemists published the findings of an experiment in the American Institute of Chemical Engineers Journal. Brian Gettelfinger, an accomplished swimmer, swam through about 600 pounds of a syrup substitute—an edible thickener called guar gum—using backstroke, breaststroke, butterfly and freestyle. His times were nearly identical to those in water. “Because the human body is not optimized for swimming, we create a ridiculous amount of turbulence, which we then fight in our struggle to pull ourselves through the water,” Poundstone explains in his book. “The turbulence produces much more drag than the viscosity does. Relatively speaking, the viscosity hardly matters.”

Unless you majored in physics or read obscure journals, you probably didn’t know that. Poundstone recommends that anyone who faces the question in an interview should ask why such an experiment is even necessary. ‘The dynamics of liquids and gases is a textbook example of chaos,” he notes. “It is so dependent on the granular details as to defy prediction. That’s why aircraft designers need wind tunnels to test their designs.”