Unlike most other holidays, the history of April Fools' Day. Sometimes called All Fools' Day, is not as the totally clear. The only point in time that can be agreed on as the beginning of this tradition was 1582,in France. Before that year, the New Year was celebrated for eight days, beginning  on March 25.The reform of the calendar celetxration reached the highest point on April l_With the riform of the calendar under Charles 1X,the Gregorian calendar (公历, 阳历）was introduced, and New Year's Day was moved to January 1.

    However, because in those days communications were not as developed as they are today, many people did not receive the news for several years. Some people refused to accept the new calendar and continued to celebrate the New Year on April, These backward people were considered “foots” by other peopk. They were often sent on “fools” errands (徒劳无益的工作)or were made the taragets of jokes.

    This developed, over time, into a tradition of playing a trick on someone on the first day of April. The tradition eventully spread to England and Scotland in the eightreenth century. It was later introduced to the American colonies of both the Britain and Francc.April Fools' Day thus developed into an  international fun feast,so to speak,with different nationalities specializing in their own kind of humor at the expense of their friends and families.

    As computers become more popular in China, Chinese people are more and more depending on computer keyboards to input Chinese characters(汉字). But if they use the computer too much, they may end up forgetting the exact strokes(笔画) of each Chinese character when writing on paper. Experts suggest people, especially students, write by hand more.

    Do you write by hand more or type more? In Beijing, students start using a computer as early as primary school. And computer dependence is more widely spread among university students. Almost all their homework and essays are typed on a computer.

    All the students interviewed say they usually use a computer.

    It's faster and easier to correct if using a computer. And that's why computers are being used more and more often to modern education. But when people are taking stock in computers increasingly, problems appear.

    'When I'm writing with a pen, I find I often can't remember how to write a character, though I feel I'm familiar with it.'

    'I'm not in the mood to write when faced with a pen and paper.'

    Many students don't feel this is something to worry about. Now that it's more convenient and efficient to write on a computer, why bother to handwrite?

    Many educators think differently. Shi Liwei, headmaster of a famous primary school in the capital said, 'Chinese characters enjoy both practical and aesthetic (审美的)value. But those characters typed with computer keyboards only keep their practical value. All the artistic beauty of the characters is lost. And handwriting contains the writer's feelings. Through one's handwriting, people can get to know one's thinking and personality. Beautiful writing will give people a better first impression of them.'

    To encourage students to handwrite more, many primary schools in Beijing have made writing classes compulsory（必修的）and in universities, some professors are asking students to turn in their homework and essays written by hand.

    It's surprising how much simple movements of the body can affect the way we think. Using expansive gestures with open arms makes us feel more powerful, crossing your arms makes you more determined and lying down can bring more insights(领悟).

    So if moving the body can have these effects, what about the clothes we wear? We're all well aware of how dressing up in different ways can make us feel more attractive, sporty or professional, depending on the clothes we wear, but can the clothes actually change cognitive (认知的) performance or is it just a feeling?

    Adam and Galinsky tested the effect of simply wearing a white lab coat on people's powers of attention. The idea is that white coats are associated with scientists, who are in turn thought to have close attention to detail.

    What they found was that people wearing white coats performed better than those who weren't. Indeed, they made only half as many errors as those wearing their own clothes on the Stroop Test (one way of measuring attention). The researchers call the effect “enclothed cognition,” suggesting that all manner of different clothes probably affect our cognition in many different ways.

    This opens the way for all sorts of clothes-based experiments. Is the writer who wears a fedora more creative? Is the psychologist wearing little round glasses and smoking a cigar more insightful? Does a chef's hat make the resultant food taste better?

    From now on I will only be editing articles for PsyBlog while wearing a white coat to help keep the typing error count low. Hopefully you will be doing your part by reading PsyBlog in a cap and gown (学位服).

    Experts say there are about 6, 500 languages spoken throughout the world. But the United Nations estimates that about half of these languages are in danger of disappearing.

    One non-profit organization seeking to save world languages is a New York-based group called Wikitongues. Officials from Wikitongues say the organization has a simple goal: to provide the tools and support that people need to save their languages.

    Udell is the co-founder of Wikitongues. He said when a language disappears, many other things can go away as well. For example, parts of a community's culture, knowledge and identity can also be lost. Because of this. Udell believes the process of bringing languages back must be done by community members themselves, “from the ground up,” he said.

    “There is no way an outside organization can save someone's language for them.”

    Wikitongues was launched in 2016 as an open internet collection of world languages. The self-described “community” is operated by volunteers from around the world. The collection is in the form of language videos that people add to the Wikitongues website.

    There are currently more than 400 languages and dialects represented on Wikitongues' YouTube channel. Udell says more than 1,500 people from 70 different countries have added videos to the system.

    “We have people from India who record dozens of languages, which is beyond their own.” he said.

    One of Wikitongues'volunteers is Kolokwe, who lives in Namibia. His native language is Subiya, however, he does not get the chance to speak his native language every day. Like many other educated people from his area, he speaks a lot of English and Afrikaans.

    Kolokwe is hoping his involvement with Wikitongues call help keep Subiya and other African languages from going extinct. He wants the world to know about his language. But his goal goes beyond just sharing his language with others through video. He is also working to create a dictionary and language teaching materials that can be used in schools.

    Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri (MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

    "To provide enough power, we need certain methods with high energy density (密度)", said Jae Kwon, assistant professor of electrical and computer engineering at MU. ''The radioisotope (放射性同位素) battery can provide power density that is much higher than chemical batteries."

    Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro systems (MNEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.

    "People hear the word 'nuclear' and think of something very dangerous." he said. "However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems."

    His new idea is not only in the battery's size, but also in its semiconductor (半导体). Kwon's battery uses a liquid semi conduct or rather than a solid semiconductor.

    "The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure (晶体结构) of the solid semiconductor." Kwon said, "By using a liquid semiconductor, we believe we can minimize that problem."

    Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery. In the future, they hope to increase the battery's power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

I remember that it was a fall morning when the orchestra (管弦乐队) teachers came into Miss Newell's third-grade classroom. "You have hands for the viola(中提琴)," Miss Ciano told me. I was excited because my hands were finally good for something. I told my parents I wanted to play, and naturally, they agreed.

Since I first touched the viola, I haven't been able to put it down. Ignoring the difficulty, I am pulled closer to it each day.

Classical music is truly my best friend. It is the trusted friend of every man, woman and child. Various feelings are expressed in classical music. I discovered that when I was eleven and played a cello concerto (大提琴协奏曲) of Bach in a competition, the first movement was joyful, but the second movement was mysterious and full of pain. From the piece, I learned that music expresses not only feelings, but also sudden mood changes. By listening to classical music, I know that someone else shares these feelings. Since I am lucky enough to be able to play classical music, I am comforted by it when I am upset. It gives me a way to escape from my problems for a short period. Classical music can express my joy, sadness and anger.

Now look back at that fall day in the third grade and think how gullible I was for believing that anyone, even music teachers, could tell whether hands were perfect for a certain instrument. I'm certain they told me I had " viola hands" not because they were fortune-tellers(算命师), but because there was a lack of violists in our district. Classical music is one of the best things that ever happened to mankind. If you get introduced to it in the right way, it will become your friend for life.