The trailing edge of wind turbine blades have a serrated edge, a bit like feathers on an owl’s wing. In both cases, this reduces noise. Owls also have feathers around their legs, giving them a whisper-quiet approach to unsuspecting prey.

Golfers enjoy the benefits of a similar technique used on golf balls. As the ball flies through the air, it carries a packet of air behind, causing drag. A smooth golf ball travels only about half as far as a ball with dimples. The dimples help generate lift, and they also reduce drag. They create a thin boundary layer, which prevents the accumulation of large vortexes, and therefore the amount of air the ball has to pull.

Trout too, know how to use vortexes. They have adapted a swimming motion where they slalom between swirls. As the vortex passes, they swish their tail towards it, giving a handy push.

Contrary to popular belief, the Tacoma Bridge collapse is slightly different. The usual explanation is that the wind speed was tuned to the harmonics of the structure, which triggered a self-reinforcing oscillation. What happened was a more chaotic flutter – the wind caught the underside, flipping the roadway up. Then it’d abruptly flop down again, only to be caught again by the wind.

Response: Rod Taylor, Fuzzy Logic