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 . 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.

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.

7 . Number of Kids Watching Online Videos Doubled in 4 Years

A new study has found that the number of young Americans who watch online videos each day has more than doubled in the past four years.

The findings were based on a survey of about 1,700 young people aged 8 to 18. The group researches youth technology activity and offers guidance for parents.

The survey found that all screen time for young Americans did not change much over the past four years. On average, preteens spent just under five hours of screen time on devices (phones or computers etc.) each day. Teens had about seven and a half hours of screen time. The numbers did not include time young people spent on their devices doing homework, reading books or listening to music.

Common Sense Media’s director of research, Michael Robb, told The Associated Press that such screen time among American youth “really is the air they breathe”.

The findings suggest a continuing change by young people to move away from traditional television to watch online videos.

YouTube, which is owned by Google, was the number one choice of youth for online videos, even among the preteens surveyed.

Robb said the common use of YouTube by young people “puts a lot of pressure(压力)” on parents to find ways to limit what their children see.

In answer to the survey, YouTube said the company is rethinking the way to solve the problem.

But experts say it is easy for many children to get to the videos they want to watch, whether on YouTube or another service.

Sarah Domoff is a professor at Central Michigan University who studies the effects of technology on youth and families. She told the AP that parents often do not have the time or skills to limit what their children are watching effectively. Domoff said she thinks many parents could do more to try to track(追踪) the screen time of their children. She added, however, that tools aimed at limiting usage on services such as YouTube could be greatly improved. “It’s really hard to block out certain things unless you’re really standing over(监视) your child,” Domoff said.