Josh Hill, a biology teacher at Mar Vista High School in California, US, often gets sick after swimming in the ocean at Imperial Beach in California.

    He and a group of students are raising awareness(意识)about water pollution by taking weekly water samples(样本)of the ocean and publishing their results online.

    Every Thursday, Hill and his students collect water from the ocean. Students then take the samples to their school and test them for levels of bacteria. Usually, samples closer to the border have higher levels of bacteria, Hill said.

    “Water quality is usually the worst at the southern end and it increasingly gets better,” he said.

    Hill collects the samples on Thursdays so that students can publish the results on the Surfrider Foundation's website in time for the weekend. The Surfrider Foundation has give Mar Vista lab equipment and promote the students' results on its site.

    Most of Hill's students grew up in Imperial Beach. Many have gotten sick from the water or know someone who has.

    Cameron Bell, 17, who is currently applying to college, wants to pursue a STEM career. He appreciates the fact the he can get lab experience at school. “Our research really impacts our community because it's keeping people safe,” he said.

    On a recent Thursday morning, Anthony Gass, 15, collected some samples. Before he got into the water, his classmates helped him put on waterproof(防水的)clothes and tie a rope around his waist to protect him from the onrush of water.

    Hill said the protection probably wasn't necessary, but that it was better to be safe than to be sorry. “We just want to make sure we protect the students,” he said.

    The 67th Miss Universe beauty pageant (选美比赛) will take place December 16 in Bangkok, Thailand. The competition will include young women from around the world representing their countries. But one South American country, Chile, will not be represented by a native Chilean. Instead, Andrea Diaz, a native of Venezuela (委内瑞拉) will have that honor.

    Diaz grew up in Valencia, Venezuela. She began training as a model at age 12 at a school there. At 19, she won a pageant organized by her town's baseball team. As Diaz moved along her career path, she also moved away from home. She went first to Panama, and later to Mexico, for modeling jobs. In 2015, she settled in Chile, where most of her family members now live. The 27-year-old woman told the reporter, “I represent the new Chile. This is an inclusive (包容的) country where immigrants come in search of opportunities.”

    Thousands of people leave Venezuela each day to escape a lack of food and medicine in the country. Its economic crisis (危机) has created an almost 1 million percent inflation (通货膨胀) rate. Many beauty pageant hopefuls have left Venezuela and have found work in modeling and media fields. Diaz is one of several Venezuelan beauty pageant competitors representing countries other than their homeland.

    A recent Miss Earth pageant had two Venezuelan models who competed for other countries, including Jessica Russo. Russo represented Peru just one year after moving to the country. She said, “My dream of being a beauty queen is not going to stop just because I arrived in a new country.” The 22-year-old competitor did not make it into the Miss Earth finals. But she is not giving up. She says she hopes to one day win a competition for Peru, the country where her mother was born.

    Teenagers in America know that they'll possibly need technical skills to find good jobs, but a new survey reveals that interest in technology-related careers may be decreasing.

The percentage of boys aged 13 to 17 who are interested in science, technology, engineering and math —or STEM —careers dropped from 36 percent in 2017 to 24 percent this year, according to a survey by Junior Achievement USA. The amount of girls interested in STEM careers stayed unchanged at II percent.

    But the 1, 000 survey participants still named technology as one of two key skills that will be necessary to prepare them for their future careers.

    "Kids don' t understand how technology can be applied to careers in addition to computers, and maybe robotics, "said Tammera L. Holmes, president of aviation consulting firm AeroStar Consulting （航空资询公司）.“That's all they know, so they can't really translate that interest to career pathways."

    When Holmes was in high school, her mom sent her to an event that featured (以......为专题)the pilots from World War II. One of the pilots took her for a ride and let her take the wheel immediately that was the career for me." she said.

    Women remain outnumbered(超过) by men in fields like technology. For people working to increase the number of women in these areas, the lack of growth in girls interest in STEM careers is concerning.

    Teenage girls are more interested than their male classmates in running after careers in which they can help others, said Ed Grocholski from Junior Achievement. Even with all the programs aimed at increasing girls' interest in STEM, "I don't think we really talk that much about how we improve people's lives through STEM," Grocholski said.

    Society needs to do better at making those connections for kids, said Katherine Latham, founder of an engineering firm. She used civil engineering as an example of a career that will continue to be important.

    However, the fact that students know they will need tech skills in their future careers is encouraging.

    The second skill they said they need is relationship-building.

    "That's going to be the new type of engineers," Latham said.

    After years of trying, our neighbors convinced my parents that ice fishing would be a fun winter getaway from our dairy farm. Before that, their idea of entertainment involved driving around the countryside to see how the neighbors' crops were doing.

My parents eventually built a fish house and set it up on Wood Lake. We excitedly headed for the lake on many January and February weekends. By the time we arrived at our favorite fishing spot across the lake each day, somebody had usually made a clear path across the ice. The fish houses were together at the best fishing spots, forming some kind of a neighborhood.

    Our house was large enough so all four of us could fish at the same time. Each corner had a square cut out of the floor. We sat in comfort. You'd think ice fishing would be cold, but we had a small woodstove (木炉) inside, and we put snow around the bottom of the house to keep the wind from blowing underneath.

    Besides the thrill of watching your bobber (钓鱼浮标) dip below the water, lunch was always the highlight of the day. Mom would fry pork or hamburgers in a pan. The smell of cooking meat was the envy of every other fish house in the neighborhood.

    Our days passed with a mix of quiet time and family chatter. We talked about the farm or school. And of course, we shared fishing advice. Part of the fun of ice fishing was learning to understand and trust the sounds of the frozen lake. Healthy ice "talks" as it freezes and shifts. You could often hear the sound of a crack traveling through the ice.

    People who have never tried ice fishing may not think it sounds very exciting, but it was for us. Fishing trips were an adventure. We didn't always catch fish, but we always brought home great memories of a day with family and friends.

    Every year in May, art galleries and museums prepare shows to honor Leonardo Da Vinci, who died in France on May 2, 1519. He is remembered as one of the greatest artists and creative thinkers of all time. His most famous paintings are The Mona Lisa and The Last Supper.

    Recently, researchers have been studying a painting-Landscape 8P which, they think, is Da Vinci's earliest-known artwork. They used special lighting to study the artwork and discovered there were two images(图像), not one. One drawing is on the back of the piece, which dates back to August 5, 1473.

    The drawing on the front was painted when Leonardo was 21 years old. It shows a river valley and a castle outside the city of Florence. There is little left of the drawing on the back, perhaps because it was wiped off. Only a bridge over a river can be seen. But there is writing on both sides.

    The writing on the front gives the date and goes from right to left. Some people would call this "mirror-writing". It's a way Leonardo often wrote in his notebooks. The writing on the back goes from left to right and tells about an agreement, probably to produce a work of art.

    Cecilia Frosinini is an art historian. She said, "Leonardo was born left-handed, but was taught to write with his right hand from a very young age. By looking at his writings, including from this drawing, we can see his right-handed handwriting is educated and well done. "

    Experts compared the two handwriting samples(样本)and said they were both made by Leonardo. They show he could write well using his left hand or his right hand.

    The drawing is known as Landscape 8P from its number in an art list. It will be part of an exhibit at Italy's Uffizi Gallery. The gallery director, Eike Schmidt, said by studying the drawing researchers gave us a new way of looking at Leonardo's drawing technique and his abilities in writing.

Getting rid of old tyres (轮胎) has long been a problem. Most are thrown into landfills or piled up in storage. Energy recovery is another common method. This involves burning tyres to generate electricity or heat for industries, but that produces planet warming pollution; or we use them to

repair roads, but chemicals from them might pollute the ground.

Some firms, therefore, have begun exploring an alternative. One such firm is Wastefront, which owns a big tyre-recycling plant in north-east England. In a couple of years, it will be able to turn 8 million old tyres into new products, including a black liquid called TDO (轮胎衍生油).

The process works by deconstructing a tyre into steel, rubber, and carbon black. After tearing down the steel, the remaining material is exposed to high temperatures in the absence of air to make the rubber change into a mix of hydrocarbon gases, and then they're removed. What is left behind is pure carbon black. Once the removed gases cool down, a part of them liquefies(液化) into TDO. The remaining gases are to be burned to fuel the process. This creates a closed-cycle system that prevents emissions. 

The carbon black can be reused to make new tyres. That is of interest to tyre-makers because it helps efforts to become carbon neutral—achieving a balance between the amounts of carbon dioxide produced and the carbon dioxide removed from the atmosphere. Producing new carbon black requires burning heavy oil or coal, which lets off plenty of greenhouse gases.

The recovered TDO is well-suited for making diesel ( 柴油). While not completely carbon-neutral, it does produce an 80-90% reduction in emissions of carbon dioxide, compared with the conventional fuel. The future market for such cleaner fuels will remain large, even though electric vehicles are on the rise. Fossil-fueled vehicles will exist for decades, particularly the big burners of diesel—trucks, which are harder to electrify. The fuel is also needed by trains and ships. So, anything that helps clean up overall emissions is useful—especially if it also eases a mountainous waste problem.