So, today was a welcomed change from the regular, as the garbage on my stairs was supplied by the mother of all mothers, mother nature... When I was a kid, the only thing we referred to them as was helicopters, but thanks to the second mother of all mothers the interweb, I can now supply the scientific name : maple seeds!!! (I know, I was kindof let down by that myself)
But there is science behind their helicopter-like descents, so here's the science thanks to www.grc.nasa.gov :
Maple seeds are superb autorotating helicopters. They begin rotating almost from the moment they are released from the tree. Even seeds that are poorly shaped or have badly damaged blades (wings) rotate with "ease."
Autorotation takes place because of the asymmetrical nature of maple seeds (and of paper copies). The center of mass of the seed is shifted well to one end while its center of lift is approximately in the middle. In a complicated process, the forces at work as the seed falls combine to begin a circular rotation of the seed about its center of mass. The rotation actually inscribes a cone around the axis of fall. The shape of the cone will vary depending upon the aerodynamic qualities of the seed's blade (wing). A blade with minimal lift properties will inscribe a steep-side cone while a blade with strong lift properties will inscribe a very flattened cone.
God I love sciency stuff...
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