Push and Pull Forces
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Contact and Non-Contact Forces
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Pinwheels
Most pinwheels have the blades arranged so that when wind blows straight at them, they spin anti - clockwise. This is because the blades' "cups" are made so that the oncoming air is captured and pushes the blades in this direction.
When wind is blown into the cups, the pinwheel spins well.
Consequently, if you are using a typical pinwheel, turn it so that the front side is facing your right and blow into the side of the blades. The blades will spin quickly anti-clockwise if you blow on the bottom half (into the cups) but will spin slowly clockwise if you blow on the top half (against the backs of the cups).
Similarly, if the pinwheel's front side is facing your left and you blow into the side of the blades, they will spin quickly anit-clockwise if you blow on the top half (into the cups) but will spin slowly clockwise if you blow on the bottom half (against the cups' backs).
If your pinwheel were a wind turbine, and spinning anti-clockwise turned wind energy into electrical energy, then it would most efficiently produce electricity when wind blows directly into the cups.