A cellphone is one of the few things that we hold close to our faces all the time, and yet it could possibly explode - this is what made the recent Samsung's Galaxy Note 7 smart-phone accidents so shocking.

   According to technology news website The Verge, flawed（有瑕疵的）phone batteries might be to blame.

    Even if you are not a science student, you probably know that it is common sense that the anode (the negative（负的）end of the battery) and the cathode (the positive end) should never touch. If they do, the battery will short-circuit（短路）, causing a powerful electrical reaction that can destroy the battery and cause a fire.

    This is why all lithium-ion（锂离子）batteries - the kind that can be found in many of our devices like tablets and cameras - have a separator layer inside to stop the two ends from touching one another.

    But somehow, the separators in some of the Samsung phones broke, causing explosions.

    Overcharging is another problem that can make batteries heat up quickly. Fortunately, most batteries are designed to be able to automatically stop charging once they are fully charged. But again, this somehow failed to happen in some of the Samsung phones.

    The two “somehows” may sound random（随机的）and hard to explain. But they actually both come from the fact that phone producers have been pushing the limits of batteries to meet customers' demand for a longer battery life.

    According to Lynden Archer, a materials scientist at Cornell University, US, we have already achieved 90 percent of the battery life possible from a lithium-ion battery. Customers' demand that their devices get thinner has also given producers little choice but to try to put more power into thinner batteries.

     “The more energy you put into a box, the more dangerous it's going to be,” Billy Wu, a lecturer at Imperial College London, told The Guardian.

    A thinner battery also means producers have to use thinner material for separators, and thinner material has more chance of breaking.

    If you're wondering when you might get the flu, a new study indicates you should keep an eye on your local weather report.

    According to a research published in the Journal of Clinical Virology, if you keep your eye on the weather and watch for the first major dip in the temperature, you can essentially mark your calendar in prediction for an outbreak the flu.

    To figure out how the weather and flu outbreak may be connected, researchers analyzed statistics of 20,000 people in an area over three seasons. The number of people who caught the flu was then compared with local weather data.

    After each season, the team noticed one consistent finding: The first really cold period with low outdoor temperatures and low humidity (湿度) was always followed by a week of a mass influenza outbreak.

    The researchers say that aerosol particles (气溶胶粒子) containing virus and liquid are more able to spread in cold and dry weather. So, in theory, if you sneeze or cough and the surrounding air is very dry, the air will absorb the moisture and the particles containing the virus keep spreading through the air for a longer period of time.

    Luckily there are ways to keep off the illness regardless of the weather. Washing your hands, coughing into the crook (弯曲) of your arm and getting vaccine (疫苗) are the best ways to prevent the flu from spreading. People over the age of 65, pregnant women and young children are at the highest risk of developing complications (并发症) related to the virus, according to the CDC.

    Writing it down

    Unlike some other European languages, English is a little tricky when it comes to writing. How a word is pronounced and how it is actually spelt can be very different things.

    Same spelling, different meanings

Imagine, then, a situation where two words are spelt and pronounced exactly the same way, but have completely different meanings. Welcome to the world of homonyms（同形同音异义词）. Take, for example, the word "fair"—it can be a kind of festival, an adjective to describe the colour of your hair or how you should play a game. Or "leg", which can be attached to a person, or a table and can also be a distance you travel, or a part of a competition.

Don't take it literally（字面意思）

So how do you know which meaning someone is referring to? You don't, except by the context. Obviously, if someone asks you to "give them a hand", they don't want you to remove what is at the end of your arm.

What's in a name?

    Sometimes even the context doesn't help much—the result can be amusing. These sentences play with the double meaning of a noun:

    Sentence 1: I used to be a banker, but I lost interest.

Sentence 2: A small boy swallowed some coins and had to go to hospital. When his grandmother phoned to ask how he was, the nurse said: "No change yet".

    More ambiguity（歧义）

    Sentence 3 plays with the different meanings of a verb:

    Sentence 3: I wondered why the ball was getting bigger. Then it hit me.

Double trouble

    And sometimes a word can be a noun and a verb, but have different meanings. Can you work this one out?

    Sentence 4: Time flies like an arrow. Fruit flies like a banana.

    If you like these homonyms, you will be pleased to know that English has plenty more!

    Can small, organic agriculture really feed the world? Won't we need science to produce enough food as the world population is growing to 9 billion by 2050? The answer to both questions is YES—but that science may look different than you think.

    We've been told that the only way we'll be able to feed the growing population is through the science of GM(转基因) crops and chemicals. But the latest scientific studies are saying just the opposite. In study after study, the message about agriculture is: To feed the world, we need to support sustainable (可持续的) agriculture on different, local, family farms that work with nature.

    In 2008, an international study found that sustainable agriculture, not GM crops, shows more hope of ending hunger. The International Assessment of Agricultural Knowledge, Science, and Technology for Development (known as the IAASTD), calls for a change of the world's food and farming systems.

    The Assessment said that industrial agriculture has greatly destroyed the world's soils and other natural resources, and now is doing harm to water, energy, and weather safety. The report warns that expensive, short-term ways—including GM crops—are not likely to cut down long-term hunger, and could even make environmental and social problems worse in many places.

    A recent report by the UN Environment Program shows that food problems will become more serious because of environmental problems and strongly supports sustainable agriculture on small family farms. It also showed that a worldwide change to organics could actually increase the world's food production by as much as 50%—enough to feed a population of 9 billion people with the land we have now. GM crops, once popular, are now being questioned worldwide.

You might think people all over the United States have Wi-Fi—wireless Internet service—and mobile phones. But there is no such service in Green Bank, West Virginia, a tiny town four hours from the U.S. capital, Washington D.C. Fewer than 150 people live in Green Bank, which has two churches, an elementary school and a public library. It is also home to the largest radio telescope in the world.

    There is a ban on Wi-Fi in Green Bank, along with anything else that can create electromagnetic(电磁的)waves. Officials say the waves could disturb the signals the telescope receives.

For many Americans, a visit to Green Bank is a little like returning to the 1950s. To get there, you must read road signs—because there is no GPS service in the town. People can connect with the Internet through telephones, but wireless service is not allowed.

    The observatory(天文台)is one of the largest employers in the area. The federal National Science Foundation(NSF) spends about ＄8.2 million a year to operate the observatory, telescope and educational center.

    Jonah Bauserman is a technician. If he supposes there is signal that is not allowed in the zone, he drives to the house where the signal is coming from and checks it. But once a week, when the device is cleaned, some banned devices are allowed near it.

    People in the town respect the work of the scientists. And they say they are happy to live without Wi-Fi and mobile phones. "You know, instead of sitting here on our phones and other devices we're out fishing and hunting and going to each other's houses." Everyone knows each other and communication is almost always face-to-face.

    Bees may soon need to add protein shakes to their diet. Pollen (花粉) normally provides their protein (蛋白质). But rising levels of carbon dioxide (CO₂) in the air have reduced the protein in pollen. That's what a new study finds.

    Scientists compared recently collected flowers from Canada goldenrod. Then they compared pollen in them to pollen in goldenrod reserved at a museum in Washington, DC. They found today's plants have less protein. Protein levels in pollen from the older flowers were 18 percent. Today's goldenrod pollen has only about 12 percent protein. That's about one-third less than 172 years ago. Over that same period, CO₂ levels have gone up by more than one-third. Back more than 170 years ago, they were about 280 parts per million in air. Today they are about 398 ppm.

    To test whether CO₂ changes had played a role in the falling protein levels, the researchers did some tests. They grew goldenrod for two years at CO₂ levels of up to 500 ppm. More CO₂ in the air led to lower levels of protein in the flowers' pollen.

    Joan Edwards, one of the researchers, says that this drop in pollen protein could affect a bee's diet and health. It would be like eating junk food, tasting good but offering less nutrition (营养).

    Honeybees need to eat lots of protein. They use it to feed their young. They also need it to keep their immune systems healthy, says Cédric Alaux, a bee biologist at the French agricultural research agency.

    Bee populations have been decreasing worldwide in recent years. A drop in their food quality might play a role, Edwards says. And that drop might affect crops too. "The health of the bee population is not just for the flowers and the bees and biodiversity." She worries it also could play a role in "human health and well-being."