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.

    Aunt Karen always had a special place in my heart. When I was growing up, I knew I could count on her to have room for me on her lap and words of love and encouragement when I needed to hear them. When she died five years ago, I was devastated. The whole family was still in shock when her husband, Uncle Ronnie, died a week later. I longed to have a small item of Aunt Karen's to remember her by, but seeing her children and grandchildren overcome by the grief of this double loss made me shy away from asking.

    A few months after Aunt Karen's death, I was on my way to work when I saw Rescued Treasures, a local second-hand store. I only had a couple of dollars on me and didn't really intend to buy anything, but I stopped anyway just to look inside. I had been shopping around for a few minutes when a small, black handbag caught my eye. It wasn't fancy or special. I didn't really need a handbag and continued to look around the store, but something kept drawing me back to that handbag. Finally, I checked the price tag (标签). It was just one dollar.

    The handbag stayed in the back of my car for weeks until I came upon it during a car clean-up. I opened it up. I couldn't believe it. They hadn't even cleaned it out. It was still full of junk, old candy wrappers, old receipts (收据) and used paper. Usually the store emptied things inside, so there wouldn't be any surprises for a new owner.

    I threw away some wastes, and sorted through the receipts, when I found one item in the small inside pocket. It was an insurance card with the name “Karen Stair” written on it. I began to cry. My beloved Aunt Karen. This was her handbag.

    There are about 5,000 different kinds of ladybugs(瓢虫)in the world. They are also known as lady beetles or ladybird beetles. They come in many different colors and patterns, but the best-known in North America is the seven-spotted ladybug, with its shiny, red-and-black body.

    In many cultures, ladybugs are thought to be good luck. Most people like them because they are pretty, lovely and do no harm to human beings. But farmers love them because they eat aphids and other plant-eating pests. One ladybug can eat up 5,000 insects in its lifetime!

    Most ladybugs have dome-shaped bodies with six short legs. Depending on the kind, they can have spots, stripes, or nothing at all. Seven-spotted ladybugs are red or orange with three spots on each side and one in the middle. They have a black head. Ladybugs are colorful for a reason. They tell the enemy: "Eat something else! I taste terrible." When threatened, they may play dead. Birds are ladybugs' main predators(天敌), but they are also eaten by frogs, spiders, and dragonflies.

    Ladybugs are happy in many different places, including grasslands, forests, cities, suburbs, and along rivers. Seven-spotted ladybugs are native to Europe but were brought to North America in the mid-1900s.

    Ladybugs are most active from spring until fall. When the weather turns cold, they look for a warm place to hibernate, such as in rotting logs, under rocks, or even inside houses. These hibernating places can have thousands of ladybugs.

    The name "ladybug" was given by European farmers who prayed to the Virgin Mary when pests began eating their crops. After ladybugs came and wiped out the invading insects, the farmers named them "beetle of Our Lady". This later was shortened to "lady beetle" and "ladybug".

    British chemist David Evans has become an overnight celebrity on Chinese social media. His chemistry experiments have attracted over 2 million followers in just a few months. Evans is a chemistry professor at the Beijing University of Chemical Technology. The 60-year-old always wears a white lab coat, a pair of safety goggles (护目镜), and smiles often. Some web users say he looks just like the “grandpa of KFC”.

    Evans has posted videos of various experiments. His most popular experiments have attracted millions of hits on video-sharing apps. Excited children's cheers and shouts can be heard in his videos. “I hope my experiments can arouse people's interest in science,” he says.

    Evans has been interested in China since childhood. In the early 1970s, before the reform and opening-up, he viewed it as a “country full of mysteries”. He first visited the Chinese mainland in 1987 to attend a chemistry conference in Nanjing, Jiangsu Province. He quit his job in the United Kingdom and moved to Beijing in 1996. Many of his friends thought he was crazy. But Evans says they just saw China's challenges but not its potential.

    Since 2011, Evans has turned to the Internet to popularize science. He learned short-video apps are also popular in small cities and rural areas. And he realized this enables him to reach more students, who lack opportunities to perform fun experiments. But even a one-minute video requires a considerable amount of work. Still, he thinks it's worth it to fulfill his responsibility to popularize science.

    His experiments always fill schools' lecture halls with laughter. Some viewers call him “a Harry Potter-like magician”, but he disagrees. “A magician never tells the secrets behind his tricks, but a scientist always gives an explanation.” He sees himself as a teacher. He performs experiments to spread knowledge, inspire thinking, remove misunderstandings and show that science can create change. Evans says he looks forward to more “chemical reactions” with China.

    The biggest challenge faced by travelers, especially those who like to have a backpacking trip is how to ensure a steady supply of clean clothes. Now, thanks to a great invention called Scrubba Wash Pack, that worry may be a thing of the past.

    The portable washing machine was invented by Ash Newland in 2010, while he was planning to climb Mt. Kilimanjaro. Struck by the limited packing space, he got inspiration from traditional washboards to create a bag that could be used to clean clothes. Then he quitted his career as a lawyer and focused on perfecting the bag's design. By 2012, the bag was ready for the public. It weighed only 180 grams and required very little storage space, making it perfect for anymore wishing to travel light.

    Not surprisingly, the bag which was worth 55 dollars was an instant hit with travelers, university students and even passengers. However, Newland was not satisfied. He still saw a disadvantage with his invention—dirty clothes had to be carried around in a separate bag! The recently introduced Scrubba Wash Pack solves that problem.

    In order to make the pack active, dirty clothes are placed inside the bag along with two or three liters of water. The bag is then shut tightly to ensure all air is squeezed out and the colors are massaged for a few minutes. After a quick wash, they are clean and ready to be dried. According to Newland, the pack can clean anything from jeans to smelly socks! What's even more amazing is that with a capacity to hold 13 liters of water, it can be used to wash more clothes at a time.

    The best part is that the 99-dollar pack that will be available for sale later this year, only weighs 300 grams and is completely foldable, making it easy to store when it's not in use. With the Scrubba Wash Pack, wandering through foreign cities searching for a washing shop, or paying for washing machines may soon be a thing of the past!

    In 1800, only three percent of the world's population lived in cities. Only one city — Beijing — had a population of over a million. Most people lived in rural areas, and never saw a city in their lives. In 1900, just a hundred years later, roughly 150 million people lived in cities, and the world's ten largest cities all had populations exceeding one million. By 2000, the number of city dwellers exceeded three billion; and in 2008, the world's population crossed a tipping point — more than half of the people on Earth lived in cities. By 2050, that could increase to over two-thirds. Clearly, humans have become an urban species.

    In the 19th and early 20th centuries, many people viewed cities negatively — crowded, dirty environments full of disease and crime. They feared that as cities got bigger, living conditions would worsen. In recent decades, however, attitudes have changed. Many experts now think urbanization (城市化) is good news, offering solutions to the problems of Earth's growing population.

    Harvard economist Edward Glaeser, author of The Victory of the Cir, is one such person. Glaeser argues that cities are very productive because "the absence of space between people" reduces the cost of transporting goods, people, and ideas. While the flow of goods has always been important to cities, what is most important today is the flow of ideas. Successful cities enable people to learn from each other easily, and attract and reward smart people with higher wages.

    Another urbanization supporter is environmentalist Stewart Brand. Brand believes cities help the environment because they allow haft of the world's population to live on about four percent of the land. This leaves more space for open country, such as farmland. City dwellers also have less impact per person on the environment than people in the countryside. Their roads, sewers, and power lines need fewer resources to build and operate. City apartments require less energy to heat, cool, and light. Most importantly, people in cities drive less so they produce fewer greenhouse gases per person.

    So it's a mistake to see urbanization as evil; it's a natural part of development  The challenge is how to manage the growth.