Earlier this month, two rock climbers achieved what many thought impossible: They climbed up the 3,000-foot-high Dawn Wall in Yosemite NationalPark without specialized equipment. Climbing without this equipment iscalled“free-climbing.”Until now, no one had free-climbed to the top of the rockface, which is a part of the mountain EI Capitan.

    El Capitan, which means“the captain”or“the chief”in Spanish, has always presented a challenge to climbers. But the Dawn Wall, on the mountain's southeast face, is a particularly difficult route to the summit (顶峰). It is a rock formation that is both steep and relatively smooth. This makes free-climbing the rock face seem almost impossible.

    About seven years ago, professional climber Tommy Caldwell spotted a possible route up the wall. It took years of planning and preparation, but this month, Caldwell, 36, and his friend Kevin Jorgeson, 30, finally make the climb.

    Free climbers do use ropes and other basic safety equipment to catch them if they fall — and Caldwell and Jorgeson fell often. Before starting their climb, they broke down their route into 32 sections. Each section was based on a rope length called a“pitch.”The rope was secured into the rock faceto catch the climbers if they fell.

    Caldwell and Jorgeson's goal was to climb the DawnWall without returning to the ground. If they fell, they had to start that pitch all over again. The two men started climbing on December 27. They slept in hanging tents, and a team of friends brought them food each day.

    The men had spent years rehearsing (排练) them ovements it would take to get through each pitch. They made it through the fist half of the climb relatively easily. But halfway up, Jorgeson ran into trouble. In one difficult spot, he fell each time he attempted to climb. After10 days of trying, Jorgeson finally made it to the next pitch.

    Getting through that troublesome pitch gave both climbers renewed energy. They finished the rest of the climb five days later, on January 14.

    Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

    “To provide enough power, we need certain methods with high energy density (密度)”，said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope (放射性同位素) battery can provide power density that is much higher than chemical batteries.”

    Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro/nanoelectromechanreal systems (MNEMS) Although nuclear batteries can cause concerns, Kwon said they are safe.

    “People hear the word 'nuclear' and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems.”

    His new idea is not only in the battery's size, but also in its semiconductor(半导体). Kwon's battery uses a liquid semiconductor rather than a solid semiconductor.

    “The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure(晶体结构) of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem.”

    Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery, In the future, they hope to increase the battery's power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

    Sports shoes that work out whether their owner has done enough exercise to warrant(保证；授权)time in front of the television have been invented in the UK.

    The shoes — named Square Eyes — contain an electronic pressure sensor and a tiny computer chip to record how many steps the wearer has taken in a day. A wireless transmitter(传话器) passes the information to a receiver connected to a television, and this decides how much evening viewing time the wearer deserves, based on the day's efforts.

    The design was inspired by a desire to fight against the rapidly ballooning waistlines among British teenagers, says Gillian Swan, who developed Square Eyes as a final year design project at Brunel University in London, UK. "We looked at current issues and childhood overweight really stood out," she says. "And I wanted to deal with that with my design."

    Once a child has used up their daily allowance gained through exercise, the television automatically switches off. And further time in front of the TV can only be earned through more steps.

    Swan calculated how exercise should translate to television time using the recommended daily amounts of both. Health experts suggest that a child take 12,000 steps each day and watch no more than two hours of television. So, every 100 steps recorded by the Square Eyes shoes equals exactly one minute of TV time.

    Existing pedometers(计步器) normally clip(夹在) onto a belt or slip into a pocket and keep count of steps by measuring sudden movement. Swan says these can be easily tricked into recording steps through shaking. But her shoe has been built to be harder for lazy teenagers to cheat. "It is possible, but it would be a lot of effort," she says. "That was one of my main design considerations."

    Do you ever wonder why trees begin to bud (发芽) earlier in some cities? Scientists finally found the answer but it's not very pleasant. New science suggests a relationship between light pollution and the timing when trees produce buds, which signals the arrival of the spring season.

    Light pollution is defined by the Lighting Research Center as the unwanted consequence of outdoor lighting such as street lights. Excessive (过多的) man-made light at night results in disturbed natural cycles, and also prevents the observation of stars and planets at night. But its effect on the environment goes beyond that.

    By studying some trees, researchers found out that trees that are more exposed to artificial lighting at night bud up to 7.5 days earlier than those at the natural nighttime setting. And they found out that light had a more significant effect than temperature when the buds came out. The early budding may cause problems for insects, which feed on leaves, and the birds which then feed on them in turn. Professor Richard French Constant, who helped lead the research, explained that more than the budding of trees, the study implies the danger to the balance of the ecosystem. “At the moment, caterpillars (毛毛虫) are timed to hatch to make the most of the opportunities to feed on freshly budded leaves, and birds hatch in time to feed on the young caterpillar,” he said.

    Migratory (迁徙的) birds are also negatively affected by light pollution. The glare might confuse them and make them lose their flying sense. The phenomenon might explain why some birds accidentally knock into buildings.

    Such results stress the need to pursue studies that aim to measure the effect of light pollution. If the issue were left to continue, it is estimated that by 2100, spring would begin almost a full month earlier than it does today.

    A day in the life of 18-year-old David Lanster is full of teenage activities: school, baseball practice, homework. And then he starts cooking. "Some nights I'm up until 1 a.m. making pies, or even later if we're cooking beef," said the student at Ransom Everglades High School in Florida, US.

    For the past year, Lanster and Kelly Moran, his classmate, have been hosting fancy dinner parties at Lanster's parents' home. Their meals have 17 courses and are all made by them. Their guests used to give them gifts to thank them, until the pair decided to do something nice for charity. "We got some really great Miami Heat tickets, a nice watch, and many kitchen machines," Lanster said. "But we wanted to make this something positive for people rather than us."

    Lanster and Moran focused on Common Threads, a charity(慈善机构) that helps to teach kids in poor neighborhood to cook and make healthy eating choices. The young cooks ask their guests to give however much they want as payment for their meals. It all goes to Common Threads because Lanster's parents cover their food costs. After their last 12-person event, Lanster and Moran gave $1,600 to the charity. Now, they're taking their show out of the kitchen and on the road. Lanster and Moran have started to organize private dinner parties in a similar way: the host pays for the ingredients(食材), and the guests make a donation (捐赠) to a charity.

    Outside the kitchen, the two are busy preparing their college applications. Neither is sure what they will do in the future, but they've promised their parents that they'll leave cooking alone until they finish high school.

    Since we've headed into the snowy part of the year, it seems like a good time to solve a language puzzle that Eskimos have a huge number of words for snow. The idea was popularized by the now well-known expert Benjamin Lee Whorf in the 1940s. His number was approximately five Eskimo words for snow, but somehow the story was so wide spread and romantic that it got out of control and grew bigger and bigger.

    There are two problems with the concept of Eskimos having tons of words for snow.

    First, Eskimos speak at least two different languages—Inuit and Yupik. Just as we have talked about how English and many other languages developed from a common language called Proto-Indo-European, Inuit and Yupik come from a different common language called Eskimo-Aleut. So saying Eskimos have 100 words for snow is like saying Europeans have 100 words for kings or queens. It might be telling you something broad about culture, but it isn't really telling you much about language.

    The second problem is "What is a word?” The Inuit and Yupik languages make words in different ways from how we make words in English. For example, the West Greenlandic word 'siku,' (sea ice), is used as the root for 'sikursuit (pack ice), 'Sikuliaq (new ice), and 'sikurluk (melting ice). But it's not that West Greenlandic has so many more words for describing snow than English, it's just that West Greenlandic expresses ideas by combining meaningful units of language together into one word while English uses more phrases and compounds. We express all the same ideas; we just do it a little differently because of the way our language is built.

    So you're probably still wondering, "If it's not 50 or 100 or 400 words, how many is it?" Well, Woodbury lists 15 that are present in a Yupik dictionary published in 1984, but he says that depending on how you look at it this is not an exact number. It could be 12; it could be 24. But it's certainly not 100.

    Sometimes, the "hundred words for snow" puzzle is used to argue that because Eskimos have so many words for snow, they think about snow in ways that we can't even begin to imagine—that your language decides or limits your thoughts. Languages are just different. They don't decide what we are able to think about or are not able to think about. I can think about snow floating on water even if we don't have a word for that in English.

    So when you're out skiing or snowboarding or just shoveling your driveway this winter, don't believe the people who try to tell you that Eskimos have 100 words for snow.