Everything in our body needs water to work! But sadly, not everyone has access to clean drinking water. In the US, for example, a lot of people living in the countryside get their water from wells and springs—and it can have bacteria in it.

If you drink water with bacteria in it, you might get very sick—some people even die. That’s why people living in the countryside need to clean their water before they drink it. There are a few quite efficient ways to do this. But all of them have at least one disadvantage. Iodine tablets（碘片） have negative side effects on your body if you use them for too long. Ultraviolet（紫外线的）lamps use a lot of energy and filtration（过滤）systems are expensive.

Therefore, we wanted to use a simple energy source. Everyone nowadays carries with them: a smartphone! What if we could clean water with such a common device? Wouldn’t that save a lot of trouble?

We designed a downloadable app and a cheap device that can be plugged into a smartphone to disinfect（杀毒）water（Figure. 1）.

The method that our device uses is called electrochemical disinfection. It uses electric currents（电流）to produce substances that can kill bacteria. In our experiments, we used a smartphone to produce the electric current and copper（铜）wires as a source for the antibacterial substance. Copper ions（离子）are released from the copper wire. These copper ions kill bacteria.

Copper can also be dangerous for humans but only in much higher concentrate. We tried to find the perfect balance: where just enough copper ions are released to kill the bacteria, without reaching a harmful level for humans.

With our new device, we were able to kill almost all bacteria in the treated water. Although our device worked really well, we only tested it in a limited laboratory setting—so some things could be different in real life.

We were able to clean three liters（or 8 cups）of water by only using less than 1% of the phone’s battery. However, the disinfection of these three liters took about five hours—which is too long.

Still, all of our tests suggest that it is possible to improve the speed of our device quite easily. When this is done, anyone with a smartphone can use our device to disinfect their drinking water.

Hopefully, our device will be ready for everyday use very soon!

3 . Believe in Yourself

Anita was an active girl who grew up in the eastern of Nepal. Her parents were shepherds. It was that point of the year when the sky was blue, the sun smiled upon the village and so the stars in the dark never looked brighter before. Anita found a lot of tourists visit her village. Watching people all over the world visit her village made Anita curious. "What are these people doing here, father?" asked Anita. Anita's father laughed and said, "Darling, they have all come to climb those mountains."

Amazed at their courage, Anita said, "Really, father? Is it possible to climb to the top? "

"Of course dear," replied her father, "Many people do it. "

"Someday, I will be able to climb to the highest of these mountains." said Anita with a burning dream brewing（酝酿）in her eyes. But life had other plans for her. Anita had a terrible accident when she was thirteen. Unluckily, she lost one leg. Clouds of hopelessness darkened her happy world.

"I will never be ready to climb those mountains!" cried Anita.

Her father loved her dearly. He couldn't see his little girl in pain. He was extremely sad. But he did not lose heart. He thought over and over and he couldn't sleep well. Finally, he had a good idea.

One day Anita's father built her a wooden leg, which she could wear and walk. "Never say ‘never’. Start climbing the mountains." said the determined father.

Anita was beside herself with joy. She wore the wooden leg and walked, and fell. Stood up, and tried to run, and fell again. The whole village laughed at the daddy and daughter's foolishness. But nothing pulled them down. Both the father and daughter were determined to win against all the odds. They kept practising.

After five years, Anita made it to the highest of the mountains. And she made her father very proud of her, along with her country.

4 . Do Dogs Dream?

Unlike cartoon images (图像、影像), real dogs don’t speak and describe their sleep. So you may wonder: do dogs dream like their owners?

A scientific research conducted at MIT found that during sleep, brains of humans and dogs work in a similar manner. When you or your dog first falls asleep, you experience SWS—slow wave(波) sleep—when the brain waves are slow but muscles (肌肉) are still active. Later a deeper stage of sleep happens. This stage is called REM sleep — rapid eye movements sleep. During REM, muscles are more relaxed, but the mind is more active. It was proved that both humans and dogs experience these two stages of the sleep circle. Since we know that humans dream, it is safe to conclude(做出结论) that dogs dream too.

Scientists found that as a dog falls asleep, his breathing becomes deeper and more regular(规则的). After about 20 minutes in REM sleep, dreams usually begin for normal dogs. While dreaming, the dog’s breathing may become weak and irregular, and his eyes move about behind the closed lids (眼睑) as if the dog is looking at something. By comparing brain wave patterns, researchers suggested that during REM, dogs are visualizing (呈现) dream images much like humans do during this stage of sleep.

Besides, it also found that during REM, the sleeping brain operates much like it does when awake, so both man and dogs dream about things that happen during their waking hours. Information gathered during the day is processed at night and may be relived in dreams. So your dog may “sleep run” as he runs after a cat or fetches a ball.

Studies also show that some dogs dream more than others, and the frequency and length of dreams are different according to the age and size of dogs. Young puppies usually experience more dreams than adult dogs. One possible reason is that puppies get huge amounts (数量) of new information daily and have much to process at night. Among dogs of the same age, smaller dogs seem to have more dreams than their bigger friends, but their dreams may last shorter. Dream length and frequency are also related to the amount of sleep required. A dog that has an active day outside may sleep more soundly than usual and experience longer periods of REM sleep, giving him more time to dream.

5 . There are certain things you never imagine yourself saying.

“I just got a worm(虫子) in my eye!” is one of them.

And yet I did say it—I screamed(惊叫) it, actually.

The family was all here, and we were in the garden when I saw a worm nearby. I asked my 6-year-old grandson to come over and take the worm away. He picked up the worm, studied it quickly and then threw it into the air.

The worm quickly fell back to earth, landing on my face against my left eyelid(眼皮). That’s when the screaming and the jumping up and down started.

You know how they say when you meet a small creature? The small creature is just as afraid of you as you are of it? They lie.

The worm showed no fear. I, however, am still having nightmares(噩梦) about the experience which was several days ago.

The most important thing in all this is that my grandson said he was sorry to me.

I’d just been reading a book that makes a connection between adults doing the slow and hard work of teaching manners to children and greater levels of civility(礼节) in society.

Table manners, language manners, and even manners in dress all show levels of self-control.

Having self-control limits what we say and how we behave, making many of us appear a good deal better than we really are.

Good manners also have the possibility to make mealtime a pleasant experience, even with small children.

All of my grandchildren, except the ones who can’t yet talk, asked to be excused before leaving the table.

It is a sign of respect for others at the table and a sign of respect for the meal itself. It’s also more pleasant than pushing one’s chair back and running for the back yard.

Those tall enough, and even those not tall enough, also take their dishes to the kitchen.

Manners are what civilize(教化) us—around our tables and in our families, homes and communities.

So when a little boy has the courage to apologize(道歉) to the grandma who is screaming and jumping up and down, at least we know that our years of teaching young people manners are paying off—one worm at a time.

We’ve all felt confused before. The feeling of not knowing what the answers or solutions are can make us feel useless, stupid, and cause us to worry.

People are often likely to think the person who has all of the answers is smarter than the one who asks a lot of questions. As a result, people often try to hide their confusion in different ways. People sometimes act as if they have the answers. At other times, people make guesses or create an answer even if they know it isn’t right.

But confusion might actually be a good thing. When we jump to an answer, we don’t have time to explore (探索) the thing we’re confused about. Instead of paying no attention to your confusion, accepting it and taking the opportunity to think about what’s confusing can benefit our learning. In fact, scientific studies show that confusion actually leads to deeper understanding. A 2004 study explored six moods that people feel while learning, including upset, bored, and confused. They found that students who spent more of the lesson confused learned the most. In another study, scientists tried to confuse students by giving them contradicting (矛盾的) information. Students who expressed confusion during the lesson did better on the final test. Not knowing the answer to a problem gives us space to look at different ways to solve it. The feeling of confusion also encourages us to look more deeply into the problem. In the end, this helps us understand the topic on a deeper level.

Confusion is also important for learning your identity (身份). People find out their identity in two steps. The first step is exploration, where you try out different groups and values and see what fits. The next step is commitment, when you decide firmly (坚定地) about some parts of your identity. You make up your mind that you will act in a way that fits your identity. Exploring your identity can feel very confusing. But a study found, that people who do the most exploring about who they are have better outcomes such as higher self- confidence and self-esteem (自尊) later in life.

So, instead of trying to hide your confusion, try a new method, ask for help, or research different ways to deal with the problem to work through your confusion.

School tests can be stressful. But they might also encourage you to help change the world. Three girls, Kristen, Jenna and Marisa from New York, learned about a growing problem from a reading test they took. The problem is e-waste, short for electronic waste. The girls learned some dangerous chemicals (化学品) in e-waste can harm the environment and people.

Later in the year, they had to come up with an idea for a science project. They remembered the interesting topic from their test. So the girls started a recycling drive to help other students and the community learn about properly recycling e-waste. They called themselves the E-Waste Girls.

“In our town, people recycle paper, plastic and glass, but not electronics. What can we do?” asked Marisa.

“How about asking our friends if they know how to recycle e-waste?” suggested Jenna.

The girls asked their friends, and nobody had heard anything about it. Many of their teachers didn’t know either. So they taught everyone, including their teachers, to learn about properly recycling e-waste. Then they put recycling boxes in the school hall and asked the students to collect old cell phones, radios and other items. When the boxes were full, they sent them to a special recycling center. The recyclers took out the dangerous chemicals and disposed (处理) of them properly, so that they don’t go into the air or the ground or the water.

One big way people can help reduce e-waste is by buying smartly. So the girls strongly suggested considering electronics made with” fewer dangerous chemicals and choosing electronics that will last several years.

The girls’ project also helped them become finalists in the We Can Change the World Challenge, a national student, competition. The E-Waste Girls see a bright future in which projects like theirs will not be needed any more.

10 . It is easy to forget that public education is relatively new. Even in the U.S., which has a relatively developed education system, public schools only became common in the early 19^th century. Before that, while the rich were able to get private teachers for their children, most education of children took place within the family and the community. Some people are now going back to teaching children themselves.

At one time, homeschooling was for students who had behavioral or learning difficulties. Today, there are many arguments for educating one’s children at home. Some of it starts from dissatisfaction with the normal education system. In many schools, one teacher is responsible for 30 or 40 students; children are often deprived (剥夺) of the attention they need.

Many psychologists (心理学家) see the home as the most natural learning environment, since it is supportive. Parents who homeschool say they can keep an eye on their children’s education more closely. Children can also choose what and when to study, so they can learn according to their own timetable. The many educational resources on the Internet can also be used. Supporters of homeschooling point out that homeschooled children do just as well as or better than those who are classroom-taught.

However, critics of homeschooling say that children miss out on learning important social skills because they have little interaction with their peers (同龄人). This might have a bad effect on them later in life when they go to university or start work. Critics have also raised concerns about whether parents are able to educate their children properly. Many of these parents are short of teacher training and may not be up-to-date on all the subjects taught in schools.

In the U.S., with an increasing number of parents taking their children out of class, schools are looking for ways to restore parents’ confidence in the public education system. Some American high schools have opened their doors to homeschoolers on a part-time basis, allowing these children to attend classes once or twice a week, or to take part in activities such as playing football or dancing. This enables homeschooled children to enjoy the extra benefits of peer interaction and involvement in sport or clubs.

Whatever the arguments for or against, homeschooling is growing in some countries. There are now websites and support groups that enable parents to learn more about educating their children. Homeschooling is now taken as an accepted choice to the public education system.