Science Buddies: "Ask an Expert"

Hi,
This summer I am working on a project making flowers for an outdoor installation out of recyclable materials (plastic bottles and soda cans). The flowers need to be attached to flat wooden dowels and then "planted" in the ground. I am wondering what is the best way to make these flowers so that they will spin in the wind. What could I do to make them more aerodynamic? Also what would be the best way to attach these flowers to the dowels so that they would spin like pinwheels? I tried just putting a nail half way through (leaving space so that the flower can move), but it seems like this won't last too long....Any and all ideas are appreciated!!!
-Emma

I got a lot of hits from a Google query "pinwheel from plastic jug". Quality varied but I'm pretty sure you'll get some good ideas. One caution: some of the projects described involved cutting plastic bottles with a knife, but I'd STRONGLY advise using scissors instead -- these bottles are very tough to cut, and if you work on many bottles, the odds are that eventually you will end up with a nasty cut if you use a knife. Use a good pair of scissors of course or the force needed to cut with dull or poorly meshing scissor blades could also prove risky. An alternative might be to use a small, strong, very sharp knife and wear Kevlar gloves (about ten bucks a pair at Amazon), but these gloves would be awkward for fine work I fear.