Five years ago, when I taught art at a school in Seattle, I used Tinkertoys as a test at the beginning of a term to find out something about my students. I put a small set of Tinkertoys in front of each student, and said:"Make something out of the Tinkertoys. You have 45 minutes today and 45minutes each day for the rest of the week." A few students hesitated to start. They waited to see the rest of the class would do. Several others checked the instructions and made something according to one of the model plans provided. Another group built something out of their own imaginations.

    Once I had a boy who worked experimentally with Tinkertoys in his free time. His constructions filled a shelf in the art classroom and a good part of his bedroom at home. I was delighted at the presence of such a student. Here was an exceptionally creative mind at work. His presence meant that I had an unexpected teaching assistant in class whose creativity would infect(感染) other students.

Encouraging this kind of thinking has a downside. I ran the risk of losing those students who had a different style of thinking. Without fail one would declare, "But I'm just not creative."

"Do you dream at night when you're asleep?"

"Oh, sure."

"So tell me one of your most interesting dreams." The student would tell something wildly imaginative. Flying in the sky or in a time machine or growing three heads. "That's pretty creative. Who does that for you?"

"Nobody. I do it."

"Really-at night, when you're asleep?"

"Sure."

"Try doing it in the daytime, in class, okay?"

    Dr. Sasaki knew the first-night effect probably has something to do with how humans evolved.

    The puzzle was what benefit would be gained from it when performance might be affected the following day. She also knew from previous work conducted on birds and dolphins that these animals put half of their brains to sleep at a time so that they can rest while remaining alert enough to avoid predators (捕食者). This led her to wonder if people might be doing the same thing. To take a closer look, her team studied 35 healthy people as they slept in the unfamiliar environment of the university's Department of Psychological Sciences. The participants each slept in the department for two nights and were carefully monitored with techniques that looked at the activity of their brains. Dr. Sasaki found, as expected, the participants slept less well on their first night than they did on their second, taking more than twice as long to fall asleep and sleeping less overall. During deep sleep, the participants' brains behaved in a similar manner seen in birds and dolphins. On the first night only, the left hemispheres (半球) of their brains did not sleep nearly as deeply as their right hemispheres did.

    Curious if the left hemispheres were indeed remaining awake to process information detected in the surrounding environment, Dr. Sasaki re-ran the experiment while presenting the sleeping participants with a mix of regularly timed beeps (蜂鸣声) of the same tone and irregular beeps of a different tone during the night. She worked out that, if the left hemisphere was staying alert to keep guard in a strange environment, then it would react to the irregular beeps by stirring people from sleep and would ignore the regularly timed ones. This is precisely what she found.

    Are you carrying too much on your back at your back at school? I'm sure lots of children of your age will say “Yes”. Not only the students in China have this problem, but children in the United States also have heavy school bags.

    Doctors are starting to worry that younger and younger students are having back and neck problems as a result of school bags being too heavy for them.

    “It's hard for me to go upstairs with my bag because it's so heavy,” said Rick Hammond, an 11-year-old student in the US.

    Rick is among students who have common school bags with two straps（带子）to carry them, but many other students choose rolling（有滚轮的）bags.

    But even with rolling bags, getting up stairs and buses is still a problem for children. Many of them have hurt their backs and necks because of the heavy school bags.

    But how much is too much? Doctors say students should carry no more than 10% to 15% of their own body weight.

    Scout Batch, a back doctor, said children under Grade 4 should stay with 10%. But it is also important that older children don't stay with over 15%, because their bodies are still growing.

    “Children are losing their balance and falling down with their school bags,” he said.

    Parents and teachers are starting to tell children to only take home library books they will be reading that night. Some teachers are using pieces of paper or thin workbooks for students to take home.

    One of the best answers is, as some children said, to have no homework at all!

    When you get a cut, you cover it with a bandage. How do you know when to change it? Maybe you just wait until it's wet or dirty. But when people have long-term or chronic (慢性的)wounds that take months to get better, changing bandages too early or to late could make healing take even longer. Changing the dressing on a wound too often can provide an opportunity for infections to get in. But if a bandage gets very wet very quickly from the inside, it might be filling with pus (脓)--a sign an infection has begun. Judging just when to change is important.

    Chronic wounds are common in people who are older or who have certain health conditions. Chronic wounds affect around 6.5 million people per year in the United States. When Anushka Naiknaware, 13, learned about chronic wounds, she decided to make a device that could alert a person when it's time to change their bandages.

    After a lot of trials and errors, the teen settled on a design that used an “ink” filled with carbon nanoparticles(纳米粒子). The teen loaded her ink into a printer cartridge (墨盒) to print onto her special paper, which was to be made into bandage. Well, actually, Anushka loaded her ink into many, many printer cartridges. Just changing a printer cartridge isn't easy, and filling one is even harder.

    The small printed papers cost only 5 to 10 cents, Anushka estimates. The Bluetooth sensor is more expensive, but the teen notes that it could be used over and over again. She also knows there is a long way to go before her design can help patients. It hasn't been tested on a real person yet. “You have to make sure everything works perfectly,” she says.

Dear 17-year-old self,

    When your Laker dream comes true tomorrow, you need to figure out a way to invest in the future of your family. This sounds simple, and you may think it's a no-brainer, but take some time to think on it further.

    I said INVEST.

    I did not say GIVE

    Let me explain.

    Purely giving material things to your siblings（兄弟姐妹） may appear to be right decision. So you buy them a car, a big house, pay, all of their bill. You want them to live a beautiful comfortable life, right？

    But the day will come when you realize that as much as you believed you were doing the right thing, you were actually holding them back.

    You will come to understand that you were taking care of them because it made YOU feel good, it made YOU happy to see them smiling and without a care in the world﹣and that was extremely selfish of you. While you were feeling satisfied with yourself, you were slowly eating away at their own dreams and ambitions. You were adding material things to their lives, but subtracting the most precious gifts of all.

Invest in their future, don't just give.

    Use your success, wealth and influence to put them in the best position to realize their own dreams and find their true purpose. Put them through school, set them up with job interviews and help them become leaders in their own right. Hold them to the same level of hard work and dedication that it took for you to get to where you are now, and where you will eventually go.

    I'm writing you now so that you can begin this process immediately, and so that you don't have to deal with the hurt and struggle of weaning（断绝） them off of the addiction that you facilitated That addiction only leads to anger, hatred and jealousy from everybody involved, including yourself.

    As time goes on, you will see them grow independently and have their own ambitions and their own lives, and your relationship with all of them will be much better as a result.

    Trust me, setting things up right from the beginning will avoid a ton of tears and headache, some of which remains to this day.

Much love

    Most of us might only begin to think about dinner in the late afternoon: What should I make today? But Jelena Petrovic begins to think about her big meal early each morning. After morning tea, she and her husband, Milan, begin their plans for a traditional Serbian dish. The cooking method they use probably comes from Jelena's mother or grandmother. Each recipe uses local foods found in Serbian markets.

    Milan goes to the market to get the food they need. And the 69-year-old Jelena makes plans for how she will explain the cooking process to her 150, 000 followers on YouTube. Once she is ready, Jelena films her cooking show from a small kitchen table. Milan holds the camera.

    Jelena has many years of cooking experience at home. Ten years ago, she started an online program, where she shared recipes and cooking suggestions for meat, soup, bread, sweet treats and more.

    Her number of followers grew over time. She decided to start a blog and began also making videos she filmed with her mobile phone. Today, her videos on YouTube have over 50 million views. Last year, "Granny's Kitchen" was named one of the Top 50 YouTube channels in Serbia.

    Now her YouTube channel takes up much of her day. She works from her small kitchen and home office. Colorful plants and flowers fill the room. A bright cloth covers the table where she works. She says she gets tired from cooking long hours each day. But, she said, "My viewers wait for a new recipe every morning. If I am late, they will ask if I am well or what is happening."

    Often, her viewers write that the recipes bring back happy memories of their childhood. "My recipes are all local, traditional home-food recipes," Jelena said. "I make things my mother or grandmother used to make."