One day, I received a call from a colleague. He was about to give a student a zero for his answer to a physical problem, while the student claimed a perfect score. I was elected as their arbiter（仲裁人）. I read the examination problem: “Show how it is possible to determine the height of a tall building with the aid of a barometer（气压计）. ”The student had answered; "Take the barometer to the top of the building, attach a long rope to it, lower it to the street, and then bring it up, measuring the length of the rope. The length of it is the height of the building.”

    The student had really answered the question completely, but the answer didn't confirm his competence in physics. I suggested the student try again. I gave him six minutes to answer the question, warning that the answer should show some knowledge of physics. Five minutes later, he said he had many answers and dashed off one, which read：“Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, use the physical formula（公式）to calculate the height of the building.”

    At this point, my colleague had to accept it, and then the student made almost full marks. I couldn't help asking the student what the other answers were. He listed many others, and then added, "Probably the best is to take the barometer to the administrator and said to him, ‘Sir, here is a fine barometer. If you tell me the height of the building, I will give it to you.”,

    Then, I asked the student if he really did not know the conventional answer to this question. He admitted that he did, but said that he was fed up with high school and college instructors trying to teach him how to think.

    The name of the student was Bohr who later was famous all over the world. He won the Nobel Prize for Physics in 1922.

    Next autumn when you see wild geese heading south for the winter flying in a V formation, you might think about what scientists have discovered as to why they fly that way.

    As each bird flaps its wings, it creates uplift(提升) for the bird immediately following. By flying in a V formation the whole group adds at least 71% greater flying range than if each bird flies on its own.

    People who share a common direction and sense of community can get where they are going more quickly and easily because they are traveling on the push of one another.

    When a wild goose falls out of the formation，it suddenly feels the drag and resistance of trying to go alone and quickly tries to get back into the formation to take advantage of the lifting power of the bird in front. When the head goose gets tired，it flies back into the formation and another goose flies to the front. It is wise to take turns doing difficult jobs whether it is people or wild geese flying south.

    Wild geese honk (发出雁叫声) from behind to inspire those up front to keep up their speed. What can we learn from this?

    When a wild goose gets sick or wounded by gunshots，and falls out of the formation，two other geese will fall out with that goose and follow it down to lend help and protection. They will stay with the fallen goose until it is able to fly or until it dies，and only then will they go on with their own or with another formation to catch up with their group.

    How can we reduce the risk?

    There are four general approaches to dealing with volcanic dangers. We can try to keep the danger from occurring—often an impossible task. We can try to change its path or reduce its impact on existing development. We can take steps to protect future development. We can also do our best to have disaster response plans in place before they are needed.

    Removing the Threat

    Clearly, there is no way to stop an eruption. We can, however, attempt to reduce the eruption's effects by strengthening structures, for example, building protective works such as walls to make lava (熔岩) flow away from developed areas. Such efforts can be and have been successful, but are of limited use in a large-scale eruption.

    Planning for the Future

    Protecting future development from volcanic dangers is a simple task. Before building houses, we should judge the risk. If the risk seems too great, a safer location should be found. This type of planning is very effective, but all too often, people are drawn to the lush(葱郁的)，rolling land of a quiet volcano.

     Disaster Preparedness (预案)

    When a volcano comes to life, a few weeks may not be enough time to avoid a tragedy. Planning is the key to saving lives. Well before the warning signs occur, people must be educated about volcanic dangers. Escape plans must be in place. Communication between scientists, officials, the media, and the general public should be practiced. Emergency measures must be thought out and agreed upon.

    If you doubt the importance of these efforts, take another look at past volcanic tragedies, such as the eruption of Nevado del Ruiz. Communication failures left the town of Armero unprepared for escape. When a deadly mudflow came down the slope (斜坡), 21,000 people—90 percent of the town's people—died.

    It was a cold winter day. A woman drove up to the Rainbow Bridge tollbooth(收费站). “I'm paying for myself, and for the six cars behind me,” she said with a smile, handing over seven tickets. One after another, the next six drivers arriving at the tollbooth were informed, “Some lady up ahead already paid your fare.”

    It turned out that woman, Natalie Smith, had read something on a friend's refrigerator: “Practice random (任意的 )kindness and senseless acts of beauty.” The phrase impressed her so much that she copied it down.

    Judy Foreman spotted the same phrase on a warehouse wall far away from home. When it stayed on her mind for days, she gave up and drove all the way back to copy it down. “I thought it was beautiful,” she said, explaining why she'd taken to writing it at the bottom of all her letters, “like a message from the above.” Her husband, Frank, liked the phrase so much that he put it up on the classroom wall for his students, one of whom was the daughter of Alice Johnson, a local news reporter. Alice put it in the newspaper, admitting that though she liked it, she didn't know where it came from or what it really meant.

    Two days later, Alice got a call from Anne Herbert, a woman living in Martin. It was in a restaurant that Anne wrote the phrase down on a piece of paper, after turning it around in her mind for days.

    “Here's the idea,” Anne says. “Anything you think there should be more of, do it randomly.” Her fantasies include painting the classroom of shabby schools, leaving hot meals on kitchen tables in the poor part of town, and giving money secretly to a proud old lady. Anne says, “Kindness can build on itself as much as violence can.”

    The acts of random kindness spread. If you were one of those drivers who found your fare paid, who knows what you might have been inspired to do for someone else later? Like all great events, kindness begins slowly, with every single act. Let it be yours！

    I was waiting for my train and on the subway station's floor was a man just sitting there. I looked around and nobody stopped so I just went my way. After a few steps, I turned and asked him whether he needed help. He told me his house was one station further and he would only need to take the train there. So I reached for his hand to help him stand up.

    He wanted to take the stairs but I feared that he would hurt himself since he seemed too weak to walk, so I asked him to take the elevator. Even though my mind was trying to turn the danger lights on, I put the thought that I should not go alone with a drunken man out of my mind and accompanied him on the elevator.

    We arrived on the platform with no incidents. The man's knees seemed to soften, so I asked him to rest on a bench. While sitting there, he thanked me, telling me that I saved him. No, I said, I really did nothing; he saved himself as he walked on his own feet.

    At the next station, we said our goodbyes. Before I knew it, he left 100 dollars and dashed out of the train. There was no way to give him back his money. I wanted to leave it on the seat, but a young woman who thought it belonged to me ran after me and gave me the note.

    My initial reaction to getting that money was of shame and I even felt offended. Then I thought he just wanted to thank me, the best way he knew how. Now, my question is — what act of kindness shall I do with these 100 dollars?

    Although toys packaging says it's educational, it doesn't make it so. That's the finding from a new study in JAMA Pediatrics that found some toys being marketed as language promoters got in the way of learning.

    Research shows that for kids to understand, speak and eventually read or write a language, they need to hear it - lots of it. And it's never too early for parents and to caregivers to get talking. That explains the booming industry in talking electronic toys that claim to help kids learn language.

    Professor Anna Sosa, of Northern Arizona University, led the study and says she gave families three different kinds of toys to play with: books, traditional toys like humble blocks and a shape sorter, and electronic toys. Sosa says she picked those toys because they are advertised in their packaging as language-promoters for babies between the ages of 10 and 16 months.

    "We had a talking on farm-animal names and things," Sosa says of the electronic toys. "We had a baby cell phone. And we had a baby laptop. So you open the cover and start pushing buttons, and it tells you things. The parent-child couples were asked to play separately with each type of toy over the course of three days."

    "When there's something else that's doing some talking, the parents seem to be sitting on the sidelines and letting the toy talk for them and respond for them," Sosa says. "That's bad because the best way a toy can promote language in infants and toddlers is by stimulating interaction between parent and child. There's simply no evidence that a young child can learn language directly from a toy. It isn't responsive enough. It isn't social."

    As for the other toys, traditional blocks and puzzles stimulated more conversation than the electronic toys, and books outscored them all. But don't underestimate the humble block. While traditional toys fell short of books in interaction quantity, Sosa notes, they kept pace in terms of quality.