The human athlete has a special trick that no other animal has. It is called self-talk. Athletes talk to themselves to warm up, to focus and to help themselves believe they will win. A few simple words like “I can do it!” and “It is now or never!” can make the difference between winning gold or not.

    Self-talk is also used by speakers, actors and other performers. Before a speech, politicians believe that their words will win votes. And, self-talk helps students stay calm even when stumped by hard exam questions. Self-talk is a life skill you can use wherever you are, whenever you need it.

    The whole idea of talking to themselves seems strange to many people. Imagine your teacher saying, “For homework, talk to yourself for half an hour tonight.” You might think he is playing a joke on your class. Instead, adults teach kids all about talking to other people. There are many books on why, when, what and how to communicate with the rest of the world. Thus, you can grow up knowing a lot more about people around you than about yourself.

    It is good to speak and listen to others. But there is great value in making time to listen to yourself. When you do, you get to know yourself better. Along the way, you may discover the power you have for using words well.

    Such ideas are so exciting to psychologists that they have been trying to learn more about self-talk. In the study, people found certain lost items at home more easily when they talked to themselves while searching for the things.

    You may have never heard of Lanthanum, Cerium or Neodymium, but these elements (元素) and others known as “rare earth” play a major role in modern technology. They can actually be found in many places on the earth, but not in quantities that can be mined. Only a few countries — China, America, India, Australia, Brazil and Malaysia have any that can be mined enough to be traded.

Even though some of these elements such as Cerium are as abundant as Copper, they are not found in concentrated amounts on the earth's surface. They are often mixed together with other metals, which makes extraction (提取) of these elements an expensive and an environmentally messy process. It was due to this reason that the term “rare earth” was invented.

    Rare earth metals are used widely in our life. Rechargeable car batteries, computers, iPhones, DVD players, computer monitors, televisions, lighting, lasers, glass polishing, and superconductors all use quantities of rare earth metals. Also, with the advancement in “green” technology like solar panels, these shiny materials are becoming more important than ever. An average electric car uses 10 pounds of Lanthanum for its rechargeable battery!

    America has large deposits (存储量) of rare earths and has one of the first mines. It was openedin Southern California in 1940. The element “Europium” was the first metal to be separated in quantity for use in color televisions. However, in the 1980's and 1990's, as China started producing these elements in Inner Mongolia, the mines in America and elsewhere could not keep pace. The mine in Mountain Pass, California also failed environmental regulations and shut down in 2002.

    Now, recognizing the importance of having more than one supplier of this important resource, other rare earth owning countries like India and Australia are either dusting off their rare earth mines or speeding up their production. It is believed that the debate over rare earths will become louder in the coming months and years.

    Scientists say we are all born with a knack for mathematics. Every time we scan the cafeteria for a table that will fit all of our friends, we're exercising the ancient estimation center in our brain.

    Stanislas Dehaene was the first researcher to show that this part of the brain exists. In 1989, he met Mr. N who had suffered a serious brain injury. Mr. N couldn't recognize the number 5, or add 2 and 2. But he still knew that there are “about 50 minutes” in an hour. Dehaene drew an important conclusion from his case: there must be two separate mathematical areas in our brains. One area is responsible for the math we learn in school, and the other judges approximate amounts.

    So what does the brain's estimation center do for us? Harvard University researcher Elizabeth Spelke has spent a lot of time posing math problems to preschoolers. When he asks 5-year-olds to solve a problem like 21+30, they can't do it. But he has also asked them questions such as, “Sarah has 21 candles and gets 30 more. John has 34 candles. Who has more candles?” It turns out preschoolers are great at solving questions like that. Before they've learned how to do math with numerals and symbols, their brains' approximation centers are already hard at work.

    After we learn symbolic math, do we still have any use for our inborn math sense? Justin Halberda at Johns Hopkins University gave us an answer in his study. He challenged a group of 14-year-olds with an approximation test: The kids stared at a computer screen and saw groups of yellow and blue dots flash by, too quickly to count. Then they had to say whether there had been more blue dots or yellow dots. The researchers found that most were able to answer correctly when there were 25 yellow dots and 10 blue ones. When the groups were closer in size, 11 yellow dots and 10 blue ones, fewer kids answered correctly.

    The big surprise in this study came when the researcher compared the kids' approximation test scores to their scores on standardized math tests. He found that kids who did better on the flashing dot test had better standardized test scores, and vice versa (反之亦然). It seems that, far from being irrelevant, your math sense might predict your ability at formal math.

    Today, I had the good fortune to join the students from East Silver Spring Elementary School in Maryland as they walked and biked to school in celebration of International Walk to School Day. I want to thank Principal Morrow and the entire ESS community for welcoming me so enthusiastically.

    Walk to School Day is a great opportunity for me to spend time with parents, kids, and teachers and to present our Safe Routes to School program and the First Lady Michelle Obama's Let's Move initiative（倡议）.

    As a father, grandfather and former schoolteacher, I know how important it is that we provide students with safe choice to get to school while promoting exercise and healthy lifestyles. That's why I've embraced the Safe Routes to School program so wholeheartedly since I became Secretary of Transportation.

    You know, we're looking at an increasingly sedentary（久坐的）generation of children. One out of every three kids in America is now overweight. And I admire the First Lady's effort to end this within a generation. Safe Routes to School is a natural partner for Let's Move. For more than 10 years, Safe Routes to School has been making it easier for students to walk and bike from home to school. And ESS, where I walked today, is one of the earliest schools to participate.

    We know this program has been enormously effective because of the steady increase in the number of kids walking or biking to school. And as we made our way down the street this morning I was reminded yet again of this program's extraordinary work.

    Look, walking and biking to school is good for students' health. It's good for the environment. And it's good for the entire community's quality of life.

Everybody wins when kids take Safe Routes to School.

At Englands University of Plymouth, Professor Eduardo Miranda has been programming pairs of robots to compose music. Miranda's robots have simple " vocal cords" (声带)and are programmed to sing and to listen to each other. The robots' unique warbling sounds (颤音) do not perfectly match the human voice, but each machine is exactly sharing music with the other in a new and unique way.

Each robot is equipped with speakers, software that mimics the human voice, a mouth that opens as it "sings," a microphone for ears, and a camera for eyes. The robots also move. Miranda hopes that by studying his robot vocalists, he can discover something about how and why humans create, perform, and listen to music.

When the robots sing, first one robot makes six random sounds. Its partner responds with more sounds. The first robot analyzes the sounds to see if their sequences (序列)) are similar. If they are, it nods its head and commits the sounds to memory, and the second robot notices and "memorizes" the musical sequence, too. If the first robot thinks the sounds are too different, it shakes its head and both robots ignore the sounds. Then the process continues.

Miranda set up an experiment in which he left the two robots alone in his study for two weeks. When he returned, his little warblers had, by imitating each other, not only shared notes but combined them. The product of their cooperation was far from symphonic, but the robots had begun to combine the notes into their own self-developed "songs".

With the help of his warbling robots, one of Miranda's goals is to create music that no human would ever compose. Miranda believes the robots are ideal for this purpose because they would not be influenced by any existing musical styles or rules.