The bigger the rotor blades, the more energy they can capture from the wind. The giant blades (typically 70 m or 230 feet in diameter, which is about 30 times the wingspan of an eagle) multiply the wind's force like a wheel and axle, so even a gentle breeze is enough to make the outer edges of the blades turn around.he same thing happens in a wind turbine, only the dynamo generator is driven by the turbine's rotor blades instead of by a bicycle wheel, and the lamp is a light in someone's home dozens of miles away. Read more in our main article about generators.
The fur trade is a worldwide industry dealing in the acquisition and sale of animal fur. Since the establishment of a world fur market in the early modern period, furs of boreal, polar and cold temperate mammalian animals have been the most valued.
By the end of the fur trade era, the American population was ready to move west in search of new opportunities. Due to the fur trade, the migrating pioneers ventured into a landscape that was well charted, and one about which a great deal was known.