The hottest“green”toy in Germany isn't made of organic or recycled materials.This one has a solar panel and only runs if kids remember to insert bright red “energy stones”that power the space station.Germany，a pioneer in many renewable energy initiatives，is also at the forefront of creating environment­friendly toys aimed at making kids think about where energy comes from and how much of it they can use，raising awareness through play.A number of high­tech green toys are on display at this year's Nuremberg toy fair，which runs through Sunday.

    Among them，there are hydroelectric­powered(水电动力的)toy cars，and doll houses with wind turbines and rainwater catchers.The bright green “Future Planet”space station features an inner atrium(中庭)with a fan that is powered by a functioning solar cell.Its aim is to get kids to use their imagination about how energy will be created in the future.

    Makers and retailers believe such toys will play an increasingly important role in their future—and that of our kids.“Energy is the question of the future and we are definitely thinking about this as we move ahead，”said Judith Schweinitz，a spokeswoman for Playmobil，maker of the solar panel­fitted space station.“It is increasingly being brought into our play concept.”Green toys—which range from those made of sustainable materials to ones like the space station that just raise environmental awareness—make up only a sliver of the $ 84 billion international toy market，but their share is growing，studies indicate.Environmental research firm Earthsense，based in Syracuse，New York，predicts that green toys will account for about $ 1 billion，or 5 percent of U．S.toy sales in the next five years.Parents are smart and they want information about what's in the product.That's what's really driving the market.

    Six million people visit Grand Canyon in the US every year. For the purpose of helping project Grand Canyon for your fellow visitors and future generations, please follow the guidelines below.

    Camping

    To protect the park, camping is allowed only within permitted campgrounds. Permits are required for overnight camping at the North Rim. Advance booking can be received by mail. Please write: Information Center, P.O. Box 129, Grand Canyon, AZ 86023.

    Fires

    Because of the extreme fire danger, campfires are not allowed except at Mather and Desert View campgrounds. Collection of firewood is not allowed either.

    Hiking（远足）

    Please stay on permitted paths. Otherwise you may destroy desert plants. Pack out what you pack in, so you leave no signs of your visit. It is important to keep in mind that you are in a national park where wildlife exists.

    Weather

    The weather at Grand Canyon can change very quickly. With so much rock, lightning(闪电) causes a particular danger during sudden summer storms These storms also frequently bring floods inside valleys, a danger to hikers. Watch the skies and check daily weather reports.

    Wildlife

    Do not feed park wildlife. There have been a few cases at Grand Canyon National Park where deer(鹿) were purposely shot because there are plastic bags that left them sick and weak. Hungry deer car be danger and have kicked and bitten visitors at Grand Canyon. Some other animals will also beg and bite. For your own safety and the well-being of the animals, please do not feed wildlife, no matter how gentle they may appear.

    Metal-organic frameworks(MOFs) are compounds that are set to solve some tough challenges: producing water in the desert, removing greenhouse gases from the air and storing dangerous gases more safely.

    The Arizona desert is really dry. Anyone stuck in it without water would die from dehydration (脱水) within three days. Unless, that is, they had one of Omar Yaghi's next-generation water harvesters. Although daytime humidity(湿度)is only about 10 per cent, this rises to 40 per cent at night, which means there's enough water in the atmosphere to support life — if it can be transformed into liquid form.

    That's exactly what Yaghi's device does. It's a box about the size of a small microwave oven designed to suck the humidity from the air at night and turn it into drinking water the next day using only the heat of the sun as its power source. What makes it work is a special material called a metal-organic framework (MOF), which at normal temperatures attracts water molecules (分子) onto its surface of its internal pores(细孔). Warm it up and the water is released, each harvest producing one-third of a cup of pure drinking water.

    "With further improvements, a device, the size of a washing machine, could produce enough water for the basic needs of a household," says Yaghi, a chemist at the University of California. One-third of the world's population lacks safe drinking water; for them such a device could be a lifesaver.

    These crystalline cluster(结晶群)of metals, such as aluminum or magnesium, linked by organic molecules can be made into materials with an extremely high absorption ability, attracting specific molecules to their surface. In this way, MOFs cling to a variety of liquids and gases.

MOFs work thanks to their unique structure—large quantities of nanometer-sized internal spaces. In fact one MOF has so many pores that they would cover an area as large as six football fields. MOFs are also extremely stable light and have many different uses: their molecular structure can be varied to attract specific molecules, such as water, and their pores can be designed to best store them. Adding a small amount of heat or pressure causes the MOF to release what it is holding. More than 70,000 different MOFs have been produced to date for various applications.

    Researchers are often interested in how culture changes over time. All cultures go through periods of change and some cultures change faster than others. For example, in the past 10 years, Chinese culture has changed rapidly as western products have become popular. Other countries, such as France, have created rules to prevent their culture from changing too quickly.

    Even though cultures change at different paces, the causes of cultural change are quite similar around the world. One of these is technology and medicine. In the United States the invention and development of birth control pills and other measures helped parents to limit the size of their families. As a result, families grew smaller and parents could give more attention to fewer children.  On the other hand, new technology has also created emotional distance among families.

    Cultures also change when they come into contact with other cultures. Immigration, for example, often results in cultural change for both immigrants and the host culture. Immigrants often bring with them different ideas, food, music, language, and manners when they move to a new culture. In Canada, for example, the government has a policy of multiculturalism where immigrants are encouraged to share their background cultures with Canadians while adopting and accepting Canadian culture.

    Cultural change can occur due to larger events. For example, economic depression, war, and disaster can endanger societies, which must adapt to these challenges and events. Because of these changes in society, ideas and ways of life also affect the entire culture. For example, during World War II, many American men were sent far off to fight. Consequently, women were suddenly needed to work in the factories. As a result of this change, it is no longer culturally acceptable to believe that they should not have the right to work.

    Happy, angry, amazed—these are some of the emotions we like to express these days when we're sending a message on our smart phones! That's why many of us now add little pictures to our texts to brighten up someone's mobile screen but we're also using them as a quick way of telling someone how we're feeling. Yes, emojis (表情符号) have become a popular tool for communication.

    The emoji was first invented in Japan in the late 1990s and the word "emoji" comes from the Japanese words for "picture" and "character". The number of different images has greatly increased since then and now we have a picture for nearly every mood or situation.

    Why are emojis widely used today? Professor Vyv Evans says, "Increasingly, what we're finding is that digital communication is replacing face-to-face talk in some ways. One of the reasons why emojis are so interesting is that they really do enable us to express our emotional selves much more effectively."

    Another advantage of emojis is that they are an international language—they don't use words but tell a message with pictures so they can be easily understood whatever your native language is.

    But as linguist (语言学家) Neil Cohn says, "To many, emojis are an exciting evolution (进化) of the way we communicate; but to others, they are linguistic Armageddon." It does show by using emojis, there is a lot more to our communication than words alone, but does this also mean that the traditional writing will die out one day?

    Chocolate could soon be a thing of the past, after scientists warned that the cacao plant, from which chocolate is made, could be extinct within 32 years.

    Over half of the world's chocolate comes from just two countries in West Africa­Cote d'Ivoire and Ghana­where the temperature, rain, and humidity provide the perfect conditions for cacao to grow. But the threat of rising temperatures over the next three decades caused by climate change, is expected to result in a loss of water from the ground, which scientists say could upset this balance.

    According to the related data, a temperature rise of just 2.1℃ could spell an end for the chocolate industry worldwide by 2050. Farmers in the region are already considering moving cacao production areas thousands of feet uphill into mountainous area­much of which is currently preserved for wildlife. But a move of this scale could destroy ecosystems that are already under threat from illegal farming and deforestation.

    Part of the problem, according to Doug Hawkins, is that cacao farming methods have not changed for hundreds of years. "Unlike other tree crops that have benefited from the development of modern, high yielding strains and crop management techniques to realize their genetic potential, more than 90% of the global cocoa crop is produced by small farms with unimproved planting material," he said. "It means that we could be facing a chocolate decrease of 100,000 tons a year in the next few years."

    Now scientists at the University of California at Berkeley have teamed up with American candy company Mars to keep chocolate on the menu. Using the controversial(有争议的) gene-editing technology known as CRISPR they are trying to develop a type of the cacao plant capable of surviving in dryer, warmer climates. If the team's work on the cacao plant is successful, it could remove the need for farmers in West Africa to relocate to higher ground, and perhaps even allow cacao to be grown elsewhere in the world.