A blade acts much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually[3] much stronger than the wind's force against the front side of the blade, which is called drag. The combination[4] of lift and drag causes the rotor to spin like a propeller[5], and the turning shaft spins a generator to make electricity.