You are watching a film in which two men are having a fight. They hit one another hard. At the start they only fight with their fists. But soon they begin hitting one another over the heads with chairs. And so it goes on until one of the men crashes through a window and falls thirty feet to the ground below. He is dead!

    Of course he isn't really dead. With any luck he isn't even hurt. Why? Because the men who fall out of high windows or jump from fast-moving trains, who crash cars or even catch fire, are professionals. They do this for a living. These men are called stuntmen. That is to say, they perform tricks.

    There are two sides to their work. They actually do most of the things you see on the screen. For example, they fall from a high building. However, they do not fall on to hard ground but on to empty cardboard boxes covered with a mattress. Again, when they hit one another with chairs, the chairs are made of soft wood and when they crash through windows, the glass is made of sugar!

    But although their work depends on trick of this sort, it also requires a high degree of skill and training. Often a stuntman's success depends on careful timing. For example, when he is “blown up” in a battle scene, he has to jump out of the way of the explosion just at the right moment.

    Naturally stuntmen are well paid for their work, but they lead dangerous lives. They often get seriously injured, and sometimes killed. A Norwegian stuntman, for example, skied over the edge of a cliff a thousand feet high. His parachute(降落伞) failed to open, and he was killed.

    In spite of all the risks, this is no longer a profession for men only. Men no longer dress up as women when actresses have to perform some dangerous actions. For nowadays there are stuntwomen, too!

    Think of a seed buried in a pot. It's dark down there in the potting soil. There's no light, no sunshine. So how does it know which way is up and which way is down? It does know. Seeds send shoots up toward the sky, and roots the other way. Darkness doesn't confuse them. Somehow, they get it right.

    More surprisingly, if you turn a seedling (秧苗) or a whole bunch of seedlings upside down, as Thomas Andrew Knight of the Royal Society did around 200 years ago, the tips and roots of the plant will sense, “Hey, I'm upside down. Look! I. will turn my way to the right direction and do a U-turn.”

    How do they know? According to botanist Daniel Chamovitz, Thomas Knight about 200 years ago guessed that plants must sense gravity. Knight proved it with a crazy experiment involving a spinning plate.

    He attached a bunch of plant seedlings onto a disc. The plate was then turned by a water wheel powered by a local stream at a speed of 150 revolutions (旋转) per minute for several days.

    If you have been at an amusement park in a spinning teacup, you know that because of centrifugal force (离心力) you get pushed away from the center of the spinning object toward the outside.

    Knight wondered, would the plants respond to the centrifugal pull of gravity and point their roots to the outside of the spinning plate? When he looked, that's what they'd done. Every plant on the disc had responded to the pull of gravity, and pointed its roots to the outside. The roots pointed out, and the shoots pointed in. So Thomas Knight proved that plants can and do sense the pull.

    When I was 8 years old, I decided to run away from home after a quarrel with my mother. With my suitcase(行李箱) packed and some sandwiches in a bag, I started for the front door.

    My mom asked where I was going. “I'm leaving home,” I said.

    “What's that you're carrying?” she asked.

    “Some clothes and food,” I replied.

    “If you want to run away, that's all right,” she said. “But you came into this home without anything and you can leave the same way.”

    I threw my suitcase and sandwiches on the floor and started for the door again.

    “Wait a minute,” Mom said. “You didn't have any clothes on when you arrived, and I want them back.”

    This infuriated me. I tore my clothes off — shoes, socks, underwear and all — and shouted, “Can I go now?”

    “Yes,” my mom answered, “but once you close that door, don't expect to come back.”

    I was so angry that I shut the door forcefully and stepped out of my home. Then I noticed down the street two neighbor girls walking toward our house. I was so shy that I saw the big spruce (云杉) tree in our yard and jumped under the low-hanging branches (树枝). A pile of dried-up brown needles (针状物) were beneath the tree, and you can't imagine the pain those sharp needles caused to my body.

    After I was sure the girls had passed by, I ran to the front door and knocked at it loudly.

    “It's Billy! Let me in!”

    The voice behind the door answered, “Billy doesn't live here anymore. He ran away from home.”

    Looking behind me to see if anyone else was coming down the street, I said, “Mom! I'm sorry. I'm still your son. Let me in!”

    The door opened and Mom's smiling face appeared. “Did you change your mind about running away?” she asked.

    “What's for supper?” I smiled back.

Preparing Cities for Robot Cars

    The possibility of self-driving robot cars has often seemed like a futurist's dream, years away from materializing in the real world. Well, the future is apparently now. The California Department of Motor Vehicles began giving permits in April for companies to test truly self-driving cars on public roads. The state also cleared the way for companies to sell or rent out self-driving cars, and for companies to operate driverless taxi services. California, it should be noted, isn't leading the way here. Companies have been testing their vehicles in cities across the country. It's hard to predict when driverless cars will be everywhere on our roads. But however long it takes, the technology has the potential to change our transportation systems and our cities, for better or for worse, depending on how the transformation is regulated.

    While much of the debate so far has been focused on the safety of driverless cars (and rightfully so), policymakers also should be talking about how self-driving vehicles can help reduce traffic jams, cut emissions (排放) and offer more convenient, affordable mobility options. The arrival of driverless vehicles is a chance to make sure that those vehicles are environmentally friendly and more shared.

    Do we want to copy—or even worsen—the traffic of today with driverless cars? Imagine a future where most adults own individual self-driving vehicles. They tolerate long, slow journeys to and from work on packed highways because they can work, entertain themselves or sleep on the ride, which encourages urban spread. They take their driverless car to an appointment and set the empty vehicle to circle the building to avoid paying for parking. Instead of walking a few blocks to pick up a child or the dry cleaning, they send the self-driving minibus. The convenience even leads fewer people to take public transport—an unwelcome side effect researchers have already found in ride-hailing (叫车) services.

    A study from the University of California at Davis suggested that replacing petrol-powered private cars worldwide with electric, self-driving and shared systems could reduce carbon emissions from transportation 80% and cut the cost of transportation infrastructure (基础设施) and operations 40% by 2050. Fewer emissions and cheaper travel sound pretty appealing. The first commercially available driverless cars will almost certainly be fielded by ride-hailing services, considering the cost of self-driving technology as well as liability and maintenance issues (责任与维护问题). But driverless car ownership could increase as the prices drop and more people become comfortable with the technology.

    Policymakers should start thinking now about how to make sure the appearance of driverless vehicles doesn't extend the worst aspects of the car-controlled transportation system we have today. The coming technological advancement presents a chance for cities and states to develop transportation systems designed to move more people, and more affordably. The car of the future is coming. We just have to plan for it.

The Valley Art Center energizes and encourages art appreciation in people of all ages and backgrounds through education, inspiration, and opportunities to experience the visual arts. We support art students and artists through quality curriculum and programming along with exhibition space. We promote the growth of each individual's potential and the advancement of the arts in the community.

Basic Oil Painting

This course, with a four-hour format, is for serious artists of all levels from beginners to advanced learners. Guidance will be offered on issues such as composition, colors, tools and techniques, but the emphasis of the course will be on thinking creatively. Individual attention will be available whenever needed. The course will end up with a group discussion of the students' works.

IMPORTANT: students will be responsible for bringing all necessary materials, including any desired photographic reference. Supply list is available online. And don't forget your lunch. $192/$173.

Digital Photography for the Fraidy Cat

Learn the basics of digital photography. We will start with understanding what those symbols on your camera mean. We will explore how to set your own film speed, aperture (孔径) and shutter (快门) speed. We will also learn when to use a flash. We will explore taking action shots, landscapes and family portraits (全家福). In this class you will practice and apply what you have learned using your camera! $96/$86.

Drawing for the Fraidy Cat

Everyone can draw! If you have ever wanted to learn how to draw or just want to refresh yourself in drawing basics, then this is the class for you. This class will focus on building drawing skills through the use of line, value, perspective, and composition. Students will work on a variety of projects with different drawing mediums to develop their personal style. A list of suggested supplies is available online. $96/$86.

Enamel on Metal

In this art form, drawing skills are not required for this colorful and expressive craft. Beginners learn several basic classical techniques and those with experience are guided in other techniques of choice. For those who are making jewelry, this is another form to add to your artist's toolbox!

All equipment and supplies are included in the first project fee of $8, payable to the instructor at the first class. $96/$ 86.

 Lindsey Stallworth, a high school student from Alabama, is on her way to a promising career in paleontology (古生物学) due to an unexpected discovery on family property. For years, she had been collecting fossils on their land in Monroe County, unaware of significant scientific value. However, her teacher at the Alabama School of Math and Science, Dr. Andrew Gentry, a paleontologist himself, took an interest when she showed him her collection.

" Upon examining the fossil shark teeth Lindsey presented, I quickly identified one cr: became eager to learn about its origin," said Andrew.

Lindsey guided her teacher through the rural area where she had unearthed various relics, including shark teeth. Before long, they encountered an especially significant find on the. grounds:a large bone from a 34- million- year- old whale skeleton! This led the pair to launch the huge project of uncovering the rest of the bones. After two months of hard work, they' ve managed to find the animal's skull·(颅骨),

" Assuming the entire skeleton is present, it may require several years for us to have the entire animal back in the lab," Andrew explained.

 Lindsey secured a research scholarship to persist in her fossil- digging expeditions alongside her instructor. Her enthusiasm for the project was at an all- time high, though she had never imagined a childhood pastime would lead her down this road." We would go out and pick up shark teeth and fossil shells, but we never knew anyone that could tell us anything about them," she recalled." We just thought they were cool."

" The Research Fellows Program allows Lindsey to gain real- world experience in scientific research and even present that research at professional conferences," Andrew said." It's a once- in-a- lifetime opportunity for a high school student to stand out when applying to college and maybe even discover a new career path."