The ocean can be a great place to swim and play, it may also be useful in another way. Some scientists think that waves could help make electricity.
   “Have you ever been on a surfboard or boat and felt yourself being lifted up by a wave?” asked Jamie Taylor of the Wave Energy Group in Scotland. “There is certainly a lot of energy in waves.”
   Scientists are working on using that energy to make electricity. The United States and a few other countries have started doing research on wave energy, and it is already being used in Scotland.
   Most waves are created when winds blow across the ocean. “The winds start out by making little ripples (波纹) in the water, 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 towards the coast, people can set up dams(大坝) to block the water and send it through a large wheel called a turbine(涡轮). The turbine can then power an electrical generator(发电机).
   We will never run out of wave power. Besides, wave energy does not create the same pollution as oil and coal do.
   Oceans cover three quarters of the earth's surface. That would make wave power seem perfect for creating energy around the world. But there are some disadvantages that need us to pay more attention to.
   Jamie Taylor said that wave power still cost too much money. He said that its influence on animals in the sea is still unknown. Besides, wave power would get in the way of fishing and boat traffic.
   With more research, “Many of these problems might be solved,” Taylor said. “Finding more energy sources(资源) is very important, for traditional sources of energy like oil and gas may run out some day.”
   In the future, when you turn on a light button, an ocean wave could be providing the electricity!

    What is the most stressful (有压力的) thing in school? It is probably exams. Exams can put us under a lot of stress. But some students do better under stress, while others do not. So, why do some students behave better under stress?

    It all comes down to dopamine (多巴胺). Dopamine is a chemical in our body that sends signals in the brain. It has many important roles: influencing memory, attention and how we learn.

    Our brains work best when there is a balance (平衡) of dopamine—not too much or too little. Our brains control dopamine in two ways. It either takes out dopamine quickly, or bit by bit. Exam success can be connected to how fast dopamine goes back to a balance, according to new research from the University of Missouri, reported Yahoo.

    What happens when we take an exam? If you become stressed, your brain will start to overload on dopamine. It is like a cup overflowing with water. The quicker you are able to go back to a balance of dopamine, the quicker you can focus, helping you do better on a test.

    Scientists found that, during a test, people who slowly got back to a balance of dopamine scored 8 percent lower. That's the difference between a good mark and a bad mark.

    But don't fear, there is good news for every student. The study also found that the more practice you get, the less stressed you will be. So, it turns out that     .

    If you ask soma people, "How did you learn English so well?" You may get a surprising answer, "In my sleep!"

    These are people who have taken part in one of the recent experiments to test "Learn-While-Sleep" methods, which are now being tried in several countries, and with several subjects, of which English is only one.

    Specialists say that this "sleep study" method speeds language learning greatly. They say the average person can learn two or three times as much during sleep as in the same period (时期) during the day, and does not affect his rest in any way, A word of warning, however, that sleep teaching will only strengthen in your mind what you have studied already while you are awake.

    In an experiment. lessons were broadcast (广播) over the radio. Each lesson lasted twelve hours from 8: 00 p. m. to 8: 00 a. m. The first three hours of English grammar and vocabulary were given with the students awake. At 11: 00 p. m. a lullaby was broadcast to send the student to sleep and for the next three hours the radio whispered the lesson again into his sleeping ears. At 2: 00 a. m. a sharp noise was sent over the radio to wake the sleeping student up for a few minutes to review the lesson. The cradlesong (a kind of soft song making you fail asleep easily) sent him back to rest again while the radio went on At 5: 00 a. m. his sleep ended and he had to go through the lesson again for three hours before breakfast.

    Mike Myers is a teacher at Chauncey Rose High School in Terre Haute, Indiana. Last year, he taught his students about the world's rain forests. They learned that rain forests are important because the plants and animals of the rain forests give us food, wood and medicine.

    Destruction of the world's rain forests is a severe problem. As part of a class project, Myers' students bought three acres (英亩) of rain forest in Central America. They paid $25 for each acre. The students hope that the land they bought will be protected and not destroyed.

    Last June, Myers and four of his students took a boat ride down a river. They saw alligators and crocodiles. In the middle of the week, a guide took Myers and his students into the rain forest. "The monkeys were not happy that we were in their forest. They broke small branches off the trees and threw them at us," one of the students said. "It was a great journey of exploring nature for all of us," said Myers.

    Each student close something special about Costa Rica to study involving the plants animals, food, and culture. During the last few days the group had time to do fun activation. They went whitewater rafting and horseback riding, and visited Costa Rica's active volcano.

    Myers hopes to make the trip every year with a different group of kids.

    How do you light up the night sky? The answer is by using electricity. But did you know that nature can glow (发光), too?

    Scientists have found many glowing living things. Most of them live in the ocean. Some use their lights to talk to each other. Others use them to hunt, to mate (交配) or to protect themselves. The vampire squid (幽灵蛸), for example, uses a cloud of light to scare enemies.

    Scientists around the world are looking at this kind of light for new ideas. In 2013, the US company Gleaux said it has created the world's first light-producing plant, the Daily Mail reported. It is a genetically-modified (转基因的) plant. It can glow like a firefly.

    Alexander Krichevsky, the company's founder (创始人), and other scientists hope that in the future, glowing plants could replace lamps and glowing trees could light up highways. Krichevsky also hopes the technology could be used in farming. Farmers could know when their crops need water or are ready to be picked if they glow.

    While Gleaux is working on glowing plants, the French company Glowee is trying to use glowing bacteria (细菌) to light up shop windows and street signs. It's the same type of bacteria that cause a type of squid to light up, New Scientist Online reported.

    "Our goal is to change the way we produce and use light," said Glowee founder Sandra Rey. "We want to help reduce the 19 percent of electricity consumption (消耗量) that is used to produce light.