According to sociologists(社会学家), every modern industrial society has some form of social stratification(阶层). Class, power and status are important in deciding people's rank in society.

    Class means a person's economic position in society. A commonly used classification is lower class, middle class and upper class. While sociologists disagree on how these terms should be exactly defined, they do describe societies like the United States quite well. One study shows that 53% of Americans belong to the lower class, 46% the middle class, and 1% the upper class. Interestingly, a surgeon earning $500,000 a year and a bus driver earning $50,000 a year both regard themselves as the middle class!

    Power refers to the amount of control a person has over other people. Obviously, people in positions of great power (such as governors) exercise(行使)big power, but people who take orders from others have less power. Power and class do not always go hand in hand, however. For example, the governor of a state has great power, but he or she may not belong to a corresponding (相应的)economic class. Generally, however, there is a relationship between power and class. To our knowledge, there aren't too many people who aren't millionaires in the U．S. Senate!

    Status is the honor or respect attached to a person's position in society. It can also be affected by power and class, but not necessarily so. For example, a university professor may have a high status but not belong to a high social class or have a lot of power over others.

    Far from the land of Antarctica (南极洲), a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.

    For forty years scientists have been curious about that fish. How does it live where most fish would freeze to death? It must have some secret. The Antarctic is not a comfortable place to work and research has been slow. Now it seems we have an answer.

    Research was begun by cutting holes in the ice and catching the fish. Scientists studied the fish's blood and measured its freezing point.

The fish were taken from seawater that had a temperature of -1.88℃ and many tiny pieces of ice floating in it. The blood of the fish did not begin to freeze until its temperature was lowered to

-2.05℃. That small difference is enough for the fish to live at the freezing temperature of the ice-salt mixture.

    The scientists' next research job was clear: Find out what in the fish's blood kept it from freezing. Their search led to some really strange thing made up of a protein (蛋白质) never before seen in the blood of a fish. When it was removed, the blood froze at seawater temperature. When it was put back, the blood again had its antifreeze quality and a lowered freezing point.

    Study showed that it is an unusual kind of protein. It has many small sugar molecules（分子）held in special positions within each big protein molecule. Because of its sugar content, it is called a glycoprotein. So it has come to be called the antifreeze fish glycoprotein, or AFGP.

    Eve was waiting in the corridor outside her class. She was feeling sick. She had two exams that day and physics was first. She really hated physics. It was her worst subject. Lisa looked back at her, and then looked away quickly. Eve thought she looked guilty. She didn't have a problem with physics. She didn't have a problem with anything... Miss Perfect!

    "Hi, Eve! So what's wrong with you and Lisa?" asked Tina, "I thought you were friends." "Yes, so did I," said Eve. "But she hasn't spoken to me for two weeks now. She promised to help me review for the physics exam too, but then she's ignored all my calls and texts."

    While in the exam, Eve found Lisa was holding her phone on her knee under the table and reading from it. Eve couldn't believe it! Is that how Lisa always got such good grades? She thought about telling the teacher, but she hesitated. The next exam was history. That was Eve's favorite subject but she couldn't concentrate. She didn't know what to do about Lisa. Just then, Mr. Reed, their teacher, walked past. "Mr. Reed…"

    Lisa was called to the teachers' office and there waited Mr. Reed…

    The history test was over. Eve was walking towards the school gate when she heard footsteps behind her. It was Lisa. Eve could see that she had been crying. "Listen," said Lisa. "I'm really sorry I haven't answered your calls, but my dad had a heart attack two weeks ago and he's in hospital. He had a big heart operation today and I was very worried about him. So I was reading texts from my mum, but Mr. Reed caught me. He thought I was cheating. He believes me now, but I have to take the exam again. I'm sorry I didn't tell you what was happening. Will you forgive me?"

    There are many places to go on safari in Africa, but riding a horse through the flooded waters of Botswana's Okavango Delta must rank as one of the world's most exciting wildlife journeys.

    Several safari camps operate as the base for this adventure, providing unique rides twice a day to explore deep into the delta. The camps have excellent horses, professional guides and lots of support workers. They have a reputation for providing a great riding experience.

    The morning ride, when the guides take you to beautiful, shallow lakes full of water lilies, tends to be more active. It is unlike any other riding experience. With rainbows forming in the splashing water around you and the sound of huge drops of water bouncing off your body and face. It is truly exciting. You are very likely to come across large wild animals, too. On horseback it is possible to get quite close to elephants, giraffes and many other animals. The sense of excitement and tension levels rise suddenly though, as does your heart rate, as you move closer to them.

    In the evening, rides are usually at a more relaxed and unhurried pace. With golden light streaming across the grassy delta and the animals coming out to eat and drink. Sedate though they are, rides at this time of day are still very impressive. As the sun's rays pass through the dust kicked up by the horses, the romance of Africa comes to life.

    Back at the camp you can kick off your boots and enjoy excellent food and wine. Looking back on your day, you will find it hard to deny that a horseback Safari is as close as you will ever come to answering the call of the wild.

    On the day the tornado hit, there was no indication severe weather was on its way—the sky was blue and the sun had been out. The first alert my husband, Jimmy, 67, and I, 65, got came around 9 p.m., from some scrolling text on the TV Jimmy was watching. He ran upstairs to find me in our third-floor bedroom, and we changed the channel from the presidential primary debate I had been watching to our local Pensacola, Florida, station.

    No sooner had we found coverage of the tornado than it was on top of us. Suddenly, the bones of the house shook, the power went out, and the wind began to roar through blown-out windows. We had three flights of steps to navigate to the relative safety of the first floor, where a closet fixed underneath a brick staircase might be the firmest place to wait things out. Everything around rattling, we struggled forward, uncertain whether we would make it.

    As we reached the last flight of steps, our front door blew out. Shards of glass flew everywhere. A three-foot-long tree branch whipped, missing us by inches.

    By the time I reached the closet, the tornado had been over us for about a minute. Jimmy pushed me down to the closet floor, but the wind kept him outside. I grasped his arm as the tornado constantly sucked the door open and tried to bring him with it. My knees and scalp were full of glass, but I felt no pain. If I had let go, Jimmy would have flown right out the back of the house and into the bay. Then everything stopped. In those first quiet moments, I couldn't believe it was over.

    The storm lasted four minutes. Four of the twelve town houses in our unit were completely destroyed. Of the houses left standing, ours suffered the most damage. Amazingly, none of us were severely injured.

Science camps for kids

    Destination Science Young Inventors

    Curious minds want to know and build. Experiment & discover the technology behind controls that operate inventions: touch, sound and motion sensors. Take home a robot dog that barks, eats, and sits at your command. Invent flipping friction racers, magnetic quiz games, 3D water-powered polymers and more.

Price

    Early bird price ends

    Mar 15, 2019

    Schmahl Science Physics of Motion(运动)

    The physics of motion is all about forces. Forces need to act upon an object to get it moving, or to change its motion. In the tradition of Da Vinci, Galileo and Newton, students will explore forces as they build gliders and airplanes, design submarines, build rockets, learn about light, make roller coasters and build bridges.

Price

    Early bird price ends

    Mar 15, 2019

    Mad Science

    Junior Mad Scientists explore the kingdom of the Chemical and Physical world in this crazy week of non-stop action! Kids explore our wonder lab and find eggs that don't break, ice that doesn't melt, and discover how to freeze time! Our young chemists perform impressive hands-on experiments.

Price

    Early bird price ends

    Mar 12, 2019