What is the optimum stroke angle for a duck’s foot when paddling?
Although a duck may already intuitively know the answer, the question
has now been clarified for us humans as part of a recent research
project undertaken at the prestigious California Institute of Technology
(Caltech), in the US.

Research Scientist and Post Doctoral Scholar Dr. Daegyoum Kim performed the study along with professor Morteza Gharib. The team employed a range of experimental setups with mechanical
flappers, clappers and paddlers in tanks of fluid which was seeded with
silver-coated glass microspheres and illuminated by an Nd:YAG laser.