"Have you ever been out on a boat and felt it lifted up by a wave? Or have you jumped in the water and felt the rush of energy as waves came over you?" asked Jamie Taylor of the Wave Energy Group at the prefix = st1 /UniversityofEdinburgh."There is certainly a lot of energy in waves," he said.Scientists are working to use that energy to make electricity.Most waves are created when winds blow across the ocean."The wind starts out by making little ripples   , but if they keep on blowing, those ripples get bigger and bigger and turn into waves," Taylor said." Waves are one of nature 's ways of picking up energy and then sending it off on a journey.        When waves come toward the shore, people can set up dams to block the water and send it through a large wheel called a turbine   .The turbine can then power an electrical generator to produce electricity .        "The resource is huge," said Janet Swain of the World watch Institute."We will never run out of wave power." Besides, wave energy does not create the same pollution as other energy sources, such as oil or coal.Oceans cover three-quarters of the Earth's surface - that would make wave power seem ideal for creating energy throughout the world, though there are some weak points yet to overcome.        Swain said that wave power still costs too much money.She also said that its effects on sea animals are still unknown.What is more, wave power could affect fishing and boat traffic.        Traditional sources of energy like oil and gas may someday run out." Demand for energy to power our TVs and computers, drive our cars, and heat and cool our homes is rising rapidly throughout the world," Swain said.In the future when you turn on a light, an ocean wave could be providing the electricity! It can be inferred that some day we might not worry about   _  .
air pollution our boat traffic our power supply our supply of sea fish