"DNA Of Maple Seed Flight"
The autorotating flight path of a maple seed is visualized in a composite, multiflash photo. The seed exhibits a DNA-like flight spiral. In trying to determine how the seeds of maple trees descend so slowly, Lentink and colleagues found that by swirling, maple seeds generate a tornado-like vortex that sits atop the front leading edge of the seeds as they spin slowly to the ground. This leading-edge vortex lowers the air pressure over the upper surface of the maple seed, effectively sucking the wing upward to oppose gravity, giving it a boost. The vortex doubles the lift generated by the seeds compared to nonswirling seeds.
Image credit: David Lentink, Wageningen University