Most of us have gone away from “mad men” in the street, only to realize that they are in fact using a Bluetooth headset. Now a new University of Pennsylvania study shows that muttering can actually help people find lost objects—in other words, saying the name of an object helps you find it more quickly.

    Previous work has suggested that speaking aloud while performing step-by-step tasks, like tying shoelaces (鞋带), can help kids guide their behavior and let them focus on the job in hand. However, scientists were not sure if speaking aloud when performing tasks could help adults in the same way, especially when looking for particular objects. Professor Gary Lupan and Daniel Swingley, writing for the Quarterly Journal of Experimental Psychology, carried out some experiments. They hoped to give the fact that next time you lose your keys, muttering “keys, keys, keys” can in fact help you find them.

    Inspired by viewing people muttering to themselves as they try to find things like peanut butter in a supermarket, the researchers conducted two experiments to see if this actually worked. In the first, participants were shown 20 pictures of various objects and were asked to find a certain one, with some seeing a text label (标签) telling them what they were looking for. These participants were then asked to search for the object again while saying the word to themselves, with results showing that saying it aloud helped people find the object more quickly.

    The second experiment saw participants performing a shopping task, where they were shown photographs of items (物品) commonly found on supermarket shelves. They were asked to find all examples of a particular item, so if they were asked for apples they had to find all the bags of apples, as quickly as possible. The researchers found that there was also an advantage in saying the name of the product aloud when they were searching for something familiar.

    The University of Pennsylvania study shows that muttering can actually help people reach the target object—in other words, muttering to oneself helps to focus the mind on something. It works more effectively than seeing a written description. Repeating the word over and over again helps even more.

    In the rush to get to school, you drop a piece of toast on the floor. Do you throw it away or decide it's still OK to eat? If you're like most people, you eat it. Maybe you follow the “5-second rule”, which says foods are safe to eat if you pick them up within 5 seconds after dropping them. But you might want to think again. Scientists now say that 5 seconds is all it takes for foods to become polluted with enough bacteria to make you sick.

    Bacteria can cause many kinds of illnesses. Some kinds of bacteria can grow on food. If you eat foods on which these bacteria are growing, you can become sick.

    One of these food-borne bacteria is Salmonella. It makes 1.4 million people sick every year. Salmonella is often found in raw eggs and chicken. Cooking kills these bacteria, which is why it is so important to cook eggs, chicken, and other foods thoroughly.

    But how long does it take these bacteria to pollute food? A team of scientists in South Carolina did an experiment. First, they placed an amount of Salmonella on three surfaces: wood, tile, and carpet. They placed a piece of bread and a piece of sausage on each surface for 5, 30, or 60 seconds. After just 5 seconds, both the bread and the sausage picked up enough bacteria to make you sick.

    So, forget the 5-second rule. If your toast drops on the floor, throw it away and get another piece of clean toast. And next time, be careful not to drop it!

    The day will come when renewable energy such as wind, solar, geothermal and others replace fossil fuels as the major source of world energy. However, most analysts insist that this day will not arrive for many decades to come—certainly well past the middle of the century. Systems of fossil fuels have already been firmly set up, and it is too costly or impractical to replace the existing systems with renewables. But there are good reasons to believe that the transition (转变) to renewables will come much faster than previously thought.

    It is hardly surprising that many experts say we will see a relatively slow transition from fossil fuels to renewables, given what is known about previous energy changes of this sort. "Energy transitions take a long time," observed Vaclav Smil of the University of Manitoba in Scientific American. It took more than 50 years for coal to replace wood as the world's leading source of energy and another 50 years for oil to replace coal; the change from fossil fuels to renewables, he argued, is not likely to come any faster.

    Under ordinary circumstances, Smil's forecast would no doubt prove accurate. But these are not ordinary times. Growing concern over climate change is leading to increasingly strict controls on CO₂ and other greenhouse gas (GHG) emissions (排放), while the development in renewables technology is lowering their price and speeding their installation.

    There are, of course, many difficulties in the effective control of carbon emissions, as demonstrated by coal companies to block the introduction of new rules by the US Environmental Protection Agency. Nevertheless, it is impossible to dismiss the progress being made at the local and international levels to promote the use of renewables. The European Union (E. U), for example, is well on the way to achieving a 20% reduction in GHG emissions from 1990 levels by 2020, along with a 20% increase in the use of renewable energy.

    The transition to renewables will be faster due to dramatic improvements in the pricing and performance of such systems. As a result of the steady increases in the efficiency of wind and solar systems, together with the savings achieved through large-scale manufacture, the price of renewables is falling globally. With prices dropping this fast, solar energy is now proving competitive with fossil fuels for generating electricity in many areas.

    The change from fossil fuels to renewable energy will not come overnight, and it will not escape many setbacks. Nevertheless, renewables are likely to replace fossil fuels as the main source of electrical power well before mid-century.

    People have grown taller over the last century, with South Korean women shooting up by more than 20cm on average, and Iranian men gaining 16.5cm. A global study looked at the average height of 18-year-olds in 200 countries 1914 and 2014. The results show that while Swedes were the tallest people in the world in 1914, Dutch men have risen from l2th place to claim top spot with an average height of 182.5cm. Larvian women, meanwhile, rose from 28th place in 1914 to become the tallest in the world a century later, with an average height of 169.8cm. James Bentham, a co-author of the research says the global trend is likely but once you average over whole populations, genetics plays a less key role," he added.

    But while height has increased around the world, the trend in many countries of north and sub-Saharan Africa causes concern, says Elio Riboli of Imperial College. While height increased in Uganda and Niger during the early 20th century, the trend has reversed in recent years, with height decreasing among 18-year-olds.

    "One reason for these decreases in height is the economic situation in the 1980s," said Professor Alexander. The nutritional and health problems that followed the policy of structural adjustment, he says, led to many children and teenagers failing to reach their full potential in terms of height.

    Bentham believes the global trend of increasing height has important implications. "How tall we are now is strongly influenced by the environment we grew up in," he said. "If we give children the best possible start in life now, they will be healthier and more productive for decades to come."

    Before you make friends, you have to decide who you want to be your friends.

    Most people like to have friends who like to do the same kind of things they do.

    The quickest way to make a friend is to smile. When you smile, people think you are friendly and easy to talk to. It may not be easy at first to smile, but remember most people will stay away from a scaled or angry looking.

    One easy way to start a conversation with someone is to say something nice about him. Think about how great you feel when someone says something nice to you. Doesn't it make you want to keep talking to that person?

    Ask your new friends questions about themselves. Who's their favourite singer, where do they live, what do they do after school are all good questions to start a conversation. Make sure you have something to add to the conversation, too. Then someone asks you a question, do have an answer for it. There is nothing that will stop a conversation quicker than a shrug for an answer.

    Kids who show an interest in other kids and who are kind and friendly make good friends. Remember, everyone wants to be around people who like to do similar things and people who are nice to them.

    When Shakespeare was twenty-one, he went to London, a very interesting place, to try his fortune.

    There was the famous London Bridge and St. Paul's Cathedral, and palaces and markets and long streets full of shops.

    Then, too, there were the daily crowds where could be seen people from all over the world. Knights, scholars and the highwayman (拦路强盗）or thieves, who had been infamous for their clever robberies, passed by each other.

    Here, also, were noblemen dressed in gold, from Italy and Spain and France; slaves from Spanish America, sea captains and ministers, soldiers and servants—all held by chances or interests within the gray walls which circled London, and whose gates gave welcome to as strange a crowd as could be found in the world.

    Into this curious crowd came Shakespeare, quick to see and eager to learn. And before long all these strange sights were as familiar to him as the faces of his own town's residents. Each one told its story to him so plainly that, as before he had learned the secrets of the fields and woods, so now he learned men and men's interests that make up the great world.

    And he learned these lessons so well that when he came to write his plays, he made such use of them as no writer ever made before or since; for it is the use of this knowledge of the world, combined with his own genius, that makes Shakespeare the greatest dramatist that has ever lived.