Americans, especially the millennials（千禧一代）, are always glued（固着于）to their phones. A common day of the average university student in America starts off like this: an alarm clock wakes you up, which is quickly followed by checking social media such as Twitter and Facebook. Once in classes, you are again attracted by your buzzing phone and access to the Internet rather than pay attention to the lecturing professor. Then you have lunch with some friends, only to look up from your screen to realize that no one has said a word in five minutes and instead all are looking at their phones. Once the day ends, you can't help checking all forms of social media again before finally being able to shut your eyes only to repeat this vicious cycle the next day.

    Cyberbullying（网络霸凌）, a concept unknown before, is now in fashion. Many of the millennials are using the Internet to make jokes about others to points of extremes. The Internet gives cowards bravery; people feel like their actions and words have no bad results because they cannot see the ache it causes another.

    Millennials also think that whatever information shows up on their screens must be taken as truth, whether the material is reliable（可靠的）or not.

    Social media is not all bad, however. People are still able to use social media to connect with friends and family who live a great distance away. With a few clicks of a button, someone could make another person smile, or give words of hope and encouragement to a friend in need, or even help repair a broken relationship. Cyberspace is a vortex（漩涡）that is easy to get caught up in, but we must find a balance to keep both feet in reality while traveling across the online world.

    Brian Greene, a professor of physics and mathematics at Columbia University, has created an online science education platform. He tries to "build a bridge" with things you know about, and then "bring you across that bridge to the strange place of modern physics."

    Recently I had a chance to ask Greene about wormholes (a hole which some scientists think might exist, connecting parts of space and time that are not usually connected), time travel and other mysteries of the universe. I asked him a million-dollar question: What if I went through a wormhole and prevented my parents from meeting? "Most of us believe that the universe makes sense," Greene said. Although there are several interesting theories about time travel, he added, the laws of physics would probably prevent something so illogical from taking place. The good news is that the time paradox（悖论） is open for future physicists to solve.

    When asked how physics could become more exciting for kids, Greene said that books by Stephen Weinberg, Leonard Susskind, and other physicists, "make it a great time for people who want to learn about big ideas but aren't yet ready, perhaps, to learn math."

    When I pointed out that some students still might find physics boring, Greene said that the key is to teach them about things that are strange. "The basic stuff is important," Greene said. "But I think it's really important to also describe the more modern ideas, things like black holes and the Big Bang. If kids have those ideas in mind, then at least some of them will be excited to learn all the details．"

    Greene has followed Albert Einstein's lead in trying to solve the mysteries of the universe. Now he wants kids to do the same. As Greene said, physics is "not just a matter of solving problems in an exam." It's about experimenting, showing an interest in strange phenomena（现象）-- and having fun!

    You may have heard adults say they are uncomfortable in the morning without a cup of coffee. One reason they may feel that way is that coffee contains caffeine(咖啡因). Caffeine appears naturally in coffee, tea, and cocoa beans, which are used to make chocolate. But now food makers are adding it to many products, from potato chips to water.

    The US government is especially worried about the problem. That's why the Food and Drug Administration (FDA) is studying the health effects of caffeine on young people. Studies show that too much caffeine can make people nervous and unable to sleep. What's more, caffeine is habit- forming. Those who consume it regularly and stop suddenly may experience headaches and feel tired.

    One of the biggest concerns is the large amount of caffeine added to so-called energy drinks, like Red Bull. A 12-ounce can of cola has about 35 milligrams of caffeine. A similar serving of Red Bull contains more than three times that amount.

    The Institute of Medicine is also working on caffeine-safety measures. "Teenagers should not drink beverages that contain caffeine. They should be aware of caffeine's effects on health and on how the brain works. Take, for example, teenagers who consume caffeine to stay awake and study for a test. They will remember less of what they just studied," said Stallings, a member of the institute.

    Companies that make products with added caffeine claim they do not advertise them to kids. However, there is no law to stop children from buying them. So the FDA needs to set limits on caffeine, especially in energy drinks. As for added caffeine in foods, the government should just say no. If not, the amount of caffeine should be printed on food labels to remind consumers. The government must do that.

    Doctors say kids should avoid caffeine. If you need extra energy, try these natural boosters: eat right, exercise, and get plenty of sleep.

    American high school students are terrible writers, and one education reform group thinks it has an answer: robots. Or, more accurately, robot-readers—computers programmed to scan students' essays and spit out a grade.

    Mark Shermis, professor of the College of Education at the University of Akron, is helping to hold a contest, set up by the William and Flora Hewlett Foundation (WFHF), which promises $ 100,000 in prize money to programmers who write the best automated grading software. "If you're a high school teacher and you give a writing task, you're walking home with 150 essays," Shermis said. "You're going to need some help."

    Automated essay grading was first proposed in the 1960s, but computers back then were not up to the task. In the late 1990s, as technology improved, several textbooks and testing companies jumped into the field. Today, computers are used to grade essays on South Dakota's student writing assessments and a handful of other exams, including the TOEFL test of English fluency, taken by foreign students.

    The Hewlett contest aims to show that computers can grade as well as English teachers—only much more quickly and without all that depressing red ink. "Automated essay scoring is objective," Shermis said. "And it can be done immediately. If students finish an essay at 10 pm, they will get a result at 10: 01 pm."

    Take, for instance, the Intelligent Essay Assessor, a web-based tool marketed by Pearson Education, Inc. Within seconds, it can analyze an essay for spelling, grammar, organization, and help students to make revisions. The program scans for key words and analyzes semantic (语义的) patterns, and Pearson claims that it can understand the meaning of text much the same as a human reader.

    I'd like to share 4 of my favorite blogs with you today. I'm guessing you know about some, but I'm hoping there might be a few new treasures for you to discover.

    Design for Mankind

    A lifestyle blog by Erin Loechner, filled with beautifully written articles on everything from design to parenting, to marriage, to work, to travel and more. And I have completely enjoyed the blog for six years.

    A Cup of Jo

    A lifestyle blog by Joanna Goddard, full of free topics, questions and regular posts on everything from food, design, travel, relationships to motherhood. This is another six-year read for me.

    Enjoy it

    A lifestyle and DIY blog by Elise Blaha Cripe, full of great ideas for all things DIY (memory-keeping, home decoration, photography, gardening...). I have been following Elise's blog since ten years ago.

    Cupcakes & Cashmere

    A lifestyle and fashion blog by Emily Schuman, full of all sorts great posts on everything from fashion, to decoration, to recipes, to work, to attitudes towards life. I had always heard people talk about this blog, but didn't start following regularly until a year or two ago.

    Did you ever have to say "no" to somebody? Such as a classmate who asks to go to lunch with you? New research suggests that, at least socially, a rejection (拒绝) should not include an apology. In other words, saying you are sorry does not make the person being rejected feel any better. In fact, it might make the rejected person feel worse. That is surprising. Many people consider it to be good manners to say they are sorry when they turn down a request.

    Gili Freedman is doing some related research at Dartmouth College. For her research, she asked over 1,000 people to respond to different examples of social rejection. In one example, the researchers asked people for their reaction (反应）after a person named Taylor asked to join a co-worker who went out to lunch every Friday. And Taylor was told "no". But in some cases, the person rejecting Taylor offered an apology. In other cases, the people doing the rejection did not say they were sorry. People were asked how they would feel if they were being turned down, just as Taylor was. Most said they would be more hurt by a rejection with an apology than a rejection without an apology.

    Freedman said the reason is that apologies make people feel like they need to say that the rejection was okay— even when they felt like it was not okay. Rejection without an apology lets them express their feelings of disappointment, hurt or anger more easily. Freedman also said that an apology often makes the person doing the rejection feel better—even as it makes the person being rejected feel worse.

    Her research deals only with social communication. A business situation might be very different. "If a manager rejects a job interviewee or a boss must tell an employee that he or she is being fired from a job," Freedman said, "reactions to apologies may be different."