Parents can cut the chances of their children getting fat simply by keeping them longer at table. Just three minutes extra at a family mealtime could help prevent child obesity. Research found that among poor families, the extra minutes at mealtimes made great improvement of a normal weight for the youth. The factors are likely to be communication and the importance of a scheduled mealtime.

    Dr Barbara Fiese said, “Children, whose families have a 20-minute meal over four times a week, weigh less than kids who leave the table after 15 to 17 minutes. Over time, those extra minutes per meal add up and become really powerful.”

    The researchers studied 200 family mealtimes, testing the effects of factors and mealtime behavior of families with children in primary school. They found that families, who said that shared mealtimes were an important part of family life and had special meaning for them, were less likely to have an obese child. Similarly, families, who talked more together and interacted more positively during the meal, were more likely to have healthy-weight children.

    Teaching low-income families how to make the most of family mealtimes was a wise idea. Dr Fiese said, “This is something we can target and teach.” She added, “It's also important to recognize the increasing differences of families and their sometimes complex living arrangements that may challenge their abilities to plan ahead and arrange a single time to communicate with each other.”

    Families in poorer US neighborhoods faced a lot of problems, including poor access to healthy food. But even so, regular high quality family mealtimes made a difference to the children's weight. Dr Fiese said, “Three to four extra minutes per meal will make a healthy weight more possible.”

    How does a sunset work? We love to look at one, but Jolanda Blackwell wanted her eighth-graders to really think about it and question.

    So Blackwell had her students watch a video of a sunset as part of a physics lesson on motion. "I asked them: ' So what's moving And why' " Blackwell says. Some thought the sun was moving; others knew that a sunset is the result of the Earth spinning around on its axis. "Usually, my biggest challenge is trying to keep them patient," she says. "They just have so many burning questions."

    "Every day, we meet new information," says Charan Ranganath, a psychologist. Ranganath was curious to know why we keep some information and forget other things. So he got 19 volunteers and asked them to review more than 100 questions. When the participants' curiosity was aroused, the parts of' their brains that regulate pleasure and reward lit up. Curious minds also showed increased activity in the brain, which is involved in greater memories.

    "Curious brains are better at learning not only about the subject at hand but also dull information. This is a phenomenon teachers can use in the classroom," says Evie Malaia, a professor. "Say a kid wants to be an astronaut," she says. NL Well, how do you link that goal with learning multiplication tables(乘法表)" "A teacher may choose to ask her class an interesting word problem that involves space exploration," Malaia says. Students may remember the answer to the word problem, but they'll also remember how they found the answer through multiplication.

    What Ranganath wants to know most is why some people seem naturally more curious than others. Lots of factors, including stress, aging and certain drugs  affect dopamine(多巴胺) processing in the brain. "If we could figure these things out, we could help those who may just seem bored," Ranganath says.

    Blackwell says she doesn't have to deal with that problem too often. She says her students love exploring the mysterious unknowns in science: What happens when a car crashes. How do rainbows work "I tell my kids there's no dumb questions," Blackwell says. "That's science: asking questions and seeking answers."

New Lives for Old Phones

    When a new mobile phone starts to be sold in stores, many people rush out to buy one. We all want the newest, latest thing.{#blank#}1{#/blank#}

    Mike Townsend works at Total Recall, a mobile phone recycling company. "Don't throw your old phone away. {#blank#}2{#/blank#}If you throw it away, it goes with other rubbish to become landfill. In other words, it is put in a big hole in the ground-and it becomes a big problem," he says.

    Mobile phones contain some poisonous materials. If your phone goes to a landfill, these poisonous materials can get out and get into the water under the ground. That's the water we need to drink or water goes into rivers or the ocean. {#blank#}3{#/blank#} That's a lot of landfill and a lot of poisonous materials.

    "At Total Recall, we separate the old phones into pieces. Most of the materials in the mobile phones can be recycled and used again.{#blank#}4{#/blank#} For example, phone batteries contain nickel and cadmium. The nickel is used to make steel, and the cadmium can be used to make new batteries," explains Mike.

    "{#blank#}5{#/blank#}You can usually just take it into a mobile phone shop and they will send it to us," says Mike.

    So before you throw that old mobile phone away, use it one last time: search for a recycler near you and give them a call.

A. Send it to us and we'll recycle it.

B. Recycling your old phone is easy.

C. How much is your old mobile phone worth?

D. But what should we do with our old mobile phones?

E. Millions of mobile phones are thrown away every year.

F. We take apart the old phones and they are used to make new products.

G. Recycling materials helps keep the environment greener and cleaner.

    Scientists can figure out a movie's emotional tone from the gasps(喘气) of its audience. These gases could point the way to a subtle(微妙的，精细的) form of human communication, a new study suggests.

    "When you see a movie, you can hear the music and see the pictures. However, you don't realize here are chemical signals in the air. And they, too, could be affecting you, says Williams, who led the study. As an atmospheric chemist, he studies the chemical makeup of the air around us.

    Williams started out measuring the air in a soccer stadium. He noticed that levels of carbon dioxide and other gases changed wildly whenever the crowd cheered. That got him wondering -- Could the gases people breathe out be influenced by emotions?

    To find out, he went to the movies.

    Williams and his coworkers measured air samples collected over six weeks in two movie theaters. Overall, 9,500 movie goers watched 16 films. They included a mix of comedy, romance, action and horror films. Among them were The Hunger Games, Catching Fire, Carrie, and Walking with Dinosaurs. The researchers gave scenes from the movies such labels as "suspense(悬疑)", "laughter" and "crying". Then they looked for hundreds of chemicals in the air that showed up as people were watching particular movie scenes.

    And certain scenes had distinct chemical "fingerprints". Scenes that had people laughing or on the edge of their seats were especially distinctive. During screenings of The Hunger Games, levels of carbon dioxide and isoprene got to the highest at two suspenseful moments. Because isoprene is related to muscle movement, the researchers think tense movie moments likely led to its spikes(尖峰). Williams and his colleagues think the increase in carbon dioxide was due to the viewers' increased pulse and breathing rates.

    Scientists need more data to make stronger links between human emotions and what's in their breath. But Williams can see potential practical uses. Companies, for instance, could quickly measure the air during tests to see how people feel about new products. He pictures future studies recording other body variables(变数) as well. These might include heart rate and body temperature, for instance. "It's something to find out."

    Black Friday

    The day after Thanksgiving is the start of the holiday shopping season. Thanksgiving is always on a Thursday, so the day after is a Friday. This day has come to be known as Black Friday. It has been the busiest shopping day of the year since 2005.

    Most stores offer great deals on Black Friday. They open their doors in the small hours of the morning. They try to attract shoppers with big discounts. Some items like TVs are much cheaper than usual. Stores may even lose money on these items. They hope that shoppers will buy gifts for other people while they are in the store.

    Black Friday is a great time to get good deals. The problem is that there are not enough low-priced items to go around. Each store may only have a few. These items are in high demand. People stand in long lines to get such great deals. They may line up hours before a store opens. They may be hoping to get a low price on a TV or laptop, but not everyone who wants one will get one. Some people leave disappointed.

    The situation can be tense(紧张的). Some Black Friday events have been violent. Large, eager crowds have trampled(践踏) workers. Fights have broken out over toys or people cutting in line. People have shot one another over parking spots. But most Black Friday events are safe and fun. Still, if you plan on going, expect large crowds and a bit of pushing and shoving.

    So where does the name "Black Friday" come from? It was first used in Philadelphia in the 1950s. The police called this day Black Friday because of the heavy traffic it drew. In the 1960s, spread across the country. It seems that it is here to stay.

    Now people all over the country take part in the event known as Black Friday. It is even spreading to other parts of the world. Stores have held Black Friday events in the U.K., Australia, and Brazil since 2012. In Costa Rica Black Friday is known as "Viernes Negro." And in Mexico, stores offer an annual weekend of discounts. They call it "El Buen Fin," which means "the good weekend" in Spanish. I guess the language of savings is universal.

    Humans are social animals. They live in groups all over the world. As these groups of people live apart from other groups, over the years and centuries they develop their own habits and ideas, which are different from other cultures. One important particular side of every culture is how its people deal with time.

    Time is not very important in nonindustrial societies. The Nuer people of East Africa, for example, do not even have a word TIME that is in agreement with the abstract thing we call time. The daily lives of the people of such nonindustrial societies are likely to be patterned around their physical needs and natural events rather than around a time schedule(时间表)based on the clock. They cook and eat when they are hungry and sleep when the sun goes down. They plant crops during the growing seasons and harvest them when the crops are ripe. They measure time not by a clock or calendar(日历),but by saying that an event takes place before or after some other event Frequently such a society measures days in terms of "sleeps" or longer periods in terms of "moons." Some cultures, such as the Eskimos of Greenland measure seasons according to the migration of certain animals.

    Some cultures which do not have a written language or keep written records have developed interesting ways of "telling time". For example, when several Australian aborigines want to plan an event for a future time, one of them places a stone on a cliff or in a tree. Each day the angle of the sun changes slightly. In a few days, the rays of the sun strike the stone in a certain way. When this happens, the people see that the agreed-upon time has arrived and the event can take place.

    In contrast(成对比), exactly correct measurement of time is very important in modern, industrialized societies. This is because industrialized societies require the helpful efforts of many people in order to work. For a factory to work efficiently (well, quickly and without waste), for example, all of the workers must work at the same time. Therefore, they must know what time to start work in the morning and what time they may go home in the afternoon. Passengers must know the exact time that an airplane will arrive or depart. Students and teachers need to know when a class starts and ends. Stores must open on time in order to serve their customers. Complicated(复杂的)societies need clocks and calendars. Thus, we can see that if each person worked according to his or her own schedule, a complicated society could hardly work at all.