问答题 The sun heats the Earth"s surface unevenly causing differences in air pressure. It"s these differences that cause wind to flow over our planet"s surface. Scientists convert wind energy into electrical energy by using wind mills or wind turbines. The turbines take the movement of the air and convert it into mechanical energy. Each wind mill contains blades that are connected to a generator. The faster the blades spin the more energy that is produced by the generator. In areas that have constant winds, you will find wind farms and small, wind-driven generators. On these wind farms are hundreds of wind turbines capable of providing the electricity for entire communities. The small wind-driven generators are used for individual homes to produce electricity. Similar to solar energy, wind energy cannot be consistently used. There are areas around the world that do not have constant winds. In areas like windy mountain passes, the wind does not blow continuously. Therefore wind energy is only dependable for certain areas of the planet.