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.

    Recordings of angry bees are enough to send big, tough African elephants running away, a new study says. Beehives (蜂窝)—either recorded or real—may even prevent elephants from damaging farmer's crops.

    In 2002, scientist Lucy King and her team found that elephants avoid certain trees with bees living in them. Today, Lucy wants to see if African honeybees might discourage elephants from eating crops. But before she asked farmer to go to the trouble of setting up beehives on their farms, she needed to find out if the bees would scare elephants away.

    Lucy found a wild beehive inside a tree in northern Kenya and set up a recorder. Then she threw a stone into the beehive, which burst into life. Lucy and her assistant hid in their car until the angry bees had calmed down. Next，Lucy searched out elephant families in Samburu National Reserve in northern Kenya and put a speaker in a tree close to each family.

    From a distance, Lucy switched on the pre-recorded sound of angry bees while at the same time recording the elephants with a video camera. Half the elephant groups left the area within ten seconds. Out of a total of 17 groups, only one group ignored the sound of the angry bees. Lucy reported that all the young elephants immediately ran to their mothers to hide under them. When Lucy played the sound of a waterfall (瀑布) instead of the angry bees to many of the same elephant families, the animals were undisturbed. Even after four minutes, most of the groups stayed in one place.

    Lucy is now studying whether the elephants will continue to avoid the sound of angry bees after hearing it several times. She hasn't tested enough groups yet to know, but her initial (最初的) results were promising enough to begin trials with farmers. She has now begun placing speakers in the fields to see if elephants are frightened away.

    Are you preparing for a big test? If so, you may want to go play some basketball in between hitting the books. Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels, including those in the brain, stronger and more fully developed. Dr. Cameron claims this allows people who exercise to concentrate better. As she says, “While we already know that exercise is good for the heart, exercise can really cause physical changes in the brain.”

    The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement and physical activity show greater brain development than babies who are less physically active. With babies, even a little movement can show big results. Margaret Barnes, a pediatrician（儿科医生）, believes in the importance of exercise. She thinks that many learning disabilities that children have in elementary school or high school can be traced back to a lack of movement as babies. “Babies need movement that stimulates their five senses. They need to establish a connection between motion and memory. In this way, as they get older, children will begin to associate physical activity with higher learning,” says Margaret.

    Older people can strengthen their brains as well. Columbia University studied a group of seniors ranging in age from seventy to seventy-nine. Their study showed a short-term memory increase of up to 40 percent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for babies, exercise for older people should involve some complexity. Learning some new skills or motions, such as with yoga or tai-chi, helps to open up memory paths in the brain that may not have been used for a long time.

    For most people, any type of physical activity that increases the heart rate is helpful. The main goal is to increase the brain's flow of blood. And your brain can benefit from as little as three to four hours of exercise a week.

    In February, 2015, a South Korean woman was sleeping on the floor when her robot vacuum ate her hair, forcing her to call for emergency help. It surely isn't what Stephen Hawking warned us that intelligent devices “mean the end of the human race”. But it does highlight one of the unexpected dangers of inviting robots into our home.

    There are many examples of intelligent technology going bad, but more often than not, they involve cheating rather than physical danger. Meanwhile, increasing evidence suggests that we, especially children, tend to tell our deepest, darkest secrets to human robots. So how do we protect ourselves from giving-away code?

    Once you've invited a robot into your home, you need to manage your expectations. Movies and marketing may have told us to expect deep interaction with robots friends but we've still got a long way to go before they are as socially aware as described. Given the gulf between expectation and reality, it's important to avoid being tricked.

    The message is clear: as robots became increasingly connected to the internet, and able to respond to natural language, you need to especially cautious about figuring out who or what you are talking about.

    We also need to think about how information is being stored and shared when it comes to robots that can record our every move. Some recording devices may have been designed for entertainment but can easily be adapted for more dangerous purposes. Take Nixie, the wearable camera that can fly off your wrist at a moment's notice and take shots around you in the air. It doesn't take much imagination to see how such technology could be taken advantage of.

    If the technology around us is able to record and process speech, images and movement, or listen secretly to us, what will happen to that information? Where will it be stored? Who will have access?

    So, what is the safest way to welcome robots into our homes, public spaces, and social lives? We should be cautiously optimistic that intelligent machines could become enriching companions, while acknowledging that we need to determine strict boundaries for robots. There should be someone to turn to should your robot commit a crime, steal your card... or try to eat your hair.

    At the age of seven, while his friends were spending their allowances on candy and toys, Jose Adolfo Quisocola, from Peru, came up with the creative idea of an eco-bank, which allows kids of all ages to become economically independent and financially wise while also helping the environment.

    Established in 2012, The Bartselana Student Bank is the world's first cooperative bank for kids. Whoever wants to join has to bring in at least 5 kilograms(11 pounds)of solid waste(paper or plastic)and establish a savings goal. Once accepted, all bank "partners" are required to deposit at least one additional kilogram(2.2 pounds)of recyclables on a monthly basis and obey other requirements, such as attending financial education and environmental management workshops. The waste accumulated is sold to local recycling companies, who, thanks to some clever negotiation by Jose, pay a higher-than-market rate for everything brought in by Bartselana Student Bank members. The funds received are placed in the individual's account where they collect until his／her savings goal is reached. The account holder can then withdraw his／her money, or choose to leave it and continue to grow for a bigger target.

    "At the beginning, my teachers thought I was crazy or that a child could not undertake this type of project," Jose recalls." They did not understand that we are not the future of the country but its present. Luckily, I had the support of the school principal and an assistant in my classroom."

    The youngster's persistence paid off. Today, the eco-bank, which now has the support of several local institutions, has ten educational centers and begins accepting applications from kids all across Peru. On November 20, 2018, the young boy was awarded the famous Children's Climate Prize (CCP)."Jose's eco-bank is a brilliant way of linking economy and climate impact, both in thought and practice. The potential impact is amazing," a judge said.

    Hopefully, Jose's success will inspire more kids and adults to come up with new ideas that create value while helping the environment. As the boy says," Together we can change the world…we just need an opportune it."

    For several decades, there has been an organized campaign intended to produce distrust in science, funded by those whose interests are threatened by the findings of modern science. In response, scientists have tended to stress the success of science. After all, scientists have been right about most things, from the structure of the universe to the relativity of time and space.

    Stressing successes isn't wrong, but for many people it's not persuasive. An alternative answer to the question "Why trust science?" is that scientists use the so-called scientific method. But what is called the scientific method isn't what scientists actually do. Science is dynamic: new methods get invented; old ones get abandoned; and at any particular point, scientists can be found doing many different things. False theories sometimes lead to true results, so even if an experiment works, it doesn't prove that the theory it was designed to test is true.

    If there is no specific scientific method, then what is the basis for trust in science? The answer is the methods by which those claims are evaluated. A scientific claim is never accepted as true until it has gone through a long process of examination by fellow scientists. Scientists draft the initial version of a paper and then send it to colleagues for suggestions. Until this point, scientific feedback is typically fairly friendly. But the next step is different: the revised paper is submitted to a scientific journal, where things get a whole lot tougher. Editors deliberately send scientific papers to people who are not friends or colleagues of the authors, and the job of the reviewer is to find errors or other faults. We call this process "peer review" because the reviewers are scientific peers—experts in the same field—but they act in the role of a superior who has both the right and the responsibility to find fault. It is only after the reviewers and the editor are satisfied that any problems have been fixed that the paper will be printed in the journal and enters the body of "science."

    Some people argue that we should not trust science because scientists are "always changing their minds." While examples of truly settled science being overturned are far fewer than is sometimes claimed, they do exist. But the beauty of this scientific process is that science produces both creativity and stability. New observations, ideas, explanations and attempts to combine competing claims introduce creativity; transformative questioning leads to collective decisions and the stability of scientific knowledge. Scientists do change their minds in the face of new evidence, but this is a strength of science, not a weakness.