Are You Right Handed or Left Handed?

    Which hand do you use when write? About 8 to 15 percent of people are left handed. They often have to use tools that are designed for right-handed people. So it is difficult for left-handers to use most tools. If you are right handed, try this experiment: Take a knife with your left hand and try cutting a potato into pieces. Don't be surprised if you feel awkward（别扭的）.

    In the past, people thought it was strange to use the left hand. Young students looked down upon their left-handed classmates. Some children were even punished for using their left hand to write. But these days parents and teachers have accepted that. In almost every school in the world, left-handed students can use their left hand to write.

    What causes people to be left handed or right handed? Experts have searched long and hard on this. They concluded（得出结论） that left-handed people are left handed for the same reason that right-handed people are right handed. One out of every ten people just is a left-hander. It's simply like the color of our eyes—some people have brown eyes, while some others have black eyes.

    However, many researchers think that left-handers and right-handers are different in some aspects. Right-handers are more talkative and outgoing than left-handers. Many right-handed people understand spoken words better. For example, after they listen to directions to a supermarket, they can find it easily. Right-handers are good at organizing people, too. They are also better basketball guards. Just ask Yao Ming.

    Research shows that left-handers are creative and artistic. Many famous performers, like Jim Carrey and Paul McCartney, are left handed. Many left-handers learn better visually（在视觉方面）. In art, both Leonardo da Vinci and Michelangelo were left handed. In science, you find Newton and Einstein. The left-handed people are also really good at tennis and other single sports.

    If you prefer one hand, but you are still good at writing with the other, you are mixed handed. Research shows mixed-handers can remember everyday things better than other people. What did you eat for lunch two weeks ago? If you're mixed handed, you can probably remember.

    Albert Einstein is right once again! He thought of the idea about gravitational waves years ago with his Theory of Relativity, but scientists are finally discovering that it really exists now. But what are gravitational waves, and why are they important?

    Well, gravitational waves are made by black holes and can change time in space. Black holes aren't holes but are lots of matter put together into a very small area. They are created when a star, much like our sun, explodes and leaves behind this dense* material. It doesn't shine like a star any more, and it becomes black.

    The black holes that made these waves are special. About 1.3 billion years ago, there were two black holes that kept moving closer and closer together. Finally, they hit each other and formed one big black hole. The energy is given off and created the ripples* in space. These ripples are gravitational waves. For example, imagine you throw a stone into a pool. It creates ripples that change the shape of the water. Well, that's kind of what the influence of one black hole hitting the other has in space.

    Gravitational waves are hard to explore. But thanks to the efforts of scientists, the ripples were discovered on Feb. 11th, which is the first time in human history. Einstein was excellent to know this 100 years ago before we have the technology. It can give us a new view of the universe we live in. The discovery of gravitational waves, unlike stars, galaxies and other bright objects, black holes don't produce light, so we can't see them by tools. Gravitational waves allow scientists to look at the universe not only with light, but also with gravity. "Everything else in astronomy like the eye," A scientist told The New York Times. "Finally, astronomy grew ears. We had never ears before."

    Now, we will be able to find black holes and things that are much further away from Earth, which means much more space exploration in the future. And who knows, this discovery could even lead to time travel!