No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n'roll. Long-ago builders could have attached wooden pole s to the stones and rolled then across the sand, the scientists say.
“Technically, I think what they're proposing is possible,” physicist Daniel Bonn said.
People have long puzzled over how the Egyptians moved such huge rocks. And there's no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.
The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect workers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.
Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.

However, physicist Joseph West thinks there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , ‘Why don't they just try rolling the things?'“A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone” a lot easier to roll than a square”.
So he tried it.
He and his students tied some poles to each of four sides of a 30-kilogram stone block. That action turned the block into somewhat a wheel. Then they placed the block on the ground.
They wrapped one end of a rope around the block and pulled. The researchers found they could easily roll the block along different kinds of paths. They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.
West hasn't tested his idea on larger blocks, but he thinks rolling has clear advantages over sliding. At least, workers wouldn't have needed to carry cattle fat or water to smooth the paths.

    “We haven't found anything that we can't recycle!”

    Cigarette ends are everywhere—littering our streets and beaches—and for decades they've been thought of as “unrecyclable”. But a New Jersey based company, called TerraCycle, has taken on the challenge, and has come up with a way to recycle millions of cigarette ends and turn them into industrial plastic products. Its aim is to recycle things that people normally consider impossible to reuse.

    Obviously it would be even better for the environment if everyone just stopped smoking, but the statistics show that although there has been an increase in anti-smoking ads and messaging, between 2000 and 2014, global sales of cigarettes increased by 8 percent, and a whole lot of those cigarette ends are ending up as trash. Since most of our litter eventually ends up in waterways, cigarette ends can surely pollute the surrounding environment. “It only takes a single cigarette end to pollute a liter of water,” TerraCycle founder, Tom Szaky, said. “Animals can also mistake littered cigarette ends for food.”

    So how do you go about turning all those poisonous ends into something useful? TerraCycle does this by first breaking them down into separate parts. They mix the remaining materials, such as the tobacco and the paper, with other kinds of rubbish, and use it on non-agricultural land, such as golf courses. The filters (过滤嘴) are a little harder. To recycle these, TerraCycle first makes them clean and cuts them into small pieces, and then combines them with other recycled materials, making them into liquid for industrial plastic products.

    They're now also expanding their recycling offerings to the rest of the 80 percent of household waste that currently can't be recycled, such as chocolate packaging, pens, and mobile phones. The goal is to use the latest research to find a way to stop so much waste ending up in landfill (垃圾填埋), and then get companies to provide money for the process. And so far, it's working.

    “We haven't found anything that we can't recycle,” communications director of TerraCycle, Albe Zakes, said. “But with the amount and variety of packaging and litter in the world, we are always looking for new waste streams to address.”

    Parallel worlds exist and interact with our world, say physicists.

    Quantum mechanics (量子力学), though firmly tested, is so weird and anti-intuitive that physicist Richard Feynman once remarked, “I think I can safely say nobody understands quantum mechanics.” Attempts to explain some of the bizarre (奇异的) consequences of quantum theory have led to some mind-bending ideas, such as the Copenhagen interpretation and the many-worlds interpretation.

    Now there's a new theory on the block, called the “many interacting worlds” hypothesis (假设) (MIW), and the idea is just as profound as it sounds. The theory suggests not only parallel worlds exist, but that they interact with our world on the quantum level and are thus detectable. Though still speculative (推测的), the theory may help to finally explain some of the bizarre consequences inherent in quantum mechanics.

    The theory is a spinoff of the many-worlds interpretation in quantum mechanics—an assumption that all possible alternative histories and futures are real, each representing an actual, though parallel, world. One problem with the many-worlds interpretation, however, has been that it is fundamentally untestable, since observations can only be made in our world. Happenings in these proposed “parallel” worlds can thus only be imagined.

    MIW, however, says otherwise. It suggests that parallel worlds can interact on the quantum level, and in fact that they do.

    “The idea of parallel universes in quantum mechanics has been around since 1957,” explained Howard Wiseman, a physicist at Griffith University in Brisbane, Australia, and one of the physicists to come up with MIW. “In the well-known 'Many-Worlds Interpretation', each universe branches into a bunch of new universes every time a quantum measurement is made. All possibilities are therefore realized — in some universes the dinosaur-killing asteroid (小行星) missed Earth. In others, Australia was colonized by the Portuguese.”

    “But critics question the reality of these other universes, since they do not influence our universe at all,” he added. “On this score, our 'Many Interacting Worlds' approach is completely different, as its name implies.”

    Wiseman and colleagues have proposed that there exists “a universal force of repulsion between 'nearby'(i.e. similar) worlds, which tends to make them more dissimilar.” Quantum effects can be explained by factoring in this force, they propose.

    When asked about whether their theory might imply that humans could someday interact with other worlds, Wiseman said: “It's not part of our theory. But the idea of human interactions with other universes is no longer pure fantasy.”

    What might your life look like if you made different choices? Maybe one day you'll be able to look into one of these alternative worlds and find out.

    Directions Choose a book from the list below and bring it to class by the due date. You will have approximately one trimester，from September 14 to November 16，to read the book and complete your report. It is okay to switch your book if you do not like your original choice. Students are encouraged to check out the book of their choice from the public library.

    The purchase of a book is optional.

    In 1999, 36­year­old Tori Murden McClure became the first woman to row also (单独地) across the Atlantic Ocean, from the Canary Islands to the Caribbean. The journey of just over 5,300 kilometers took the American 81 days. Her boat, The American Pearl, was only 7 meters long.

    McClure is a real adventurer. She has been on many mountaineering expeditions, including climbs in Alaska, Kenya and Antarctica. She was also the youngest person in a team that skied 1, 200 kilometers across Antarctica to the South Pole in 1989, and became one of only two women ever to travel to the Pole by land.

    The journey across the Atlantic was her third attempt. The first time she failed because of illness, and during her second attempt, in 1998, she nearly died. She had rowed nearly 5,000 kilometers when her boat was hit by Hurricane Danielle. McClure was suddenly in the middle of 80 kph wind, and surrounded by waves that were 20 meters high. Her little boat turned over five times. McClure was sure that she was going to die­she took the video recorder that she had brought with her and recorded a farewell message to her family and friends. The hurricane continued into night, and The American Pearl turned over five more times. McClure was determined not to send a signal asking to be rescued­she didn't want other people to risk their lives, too. But after the eleventh turning over of her boat, she finally sent it and a large ship came and found her. However, they couldn't get her boat out of the rough sea­it was found months later near the coast of Portugal.

    Tori McClure had concussion (脑震荡) and a dislocated shoulder when she got home. Many people might have given up after an experience such as this, but one year later, McClure was back in her repaired boat and trying again. This time she was successful­and although she again met a hurricane on the journey, which stopped her from breaking the record for the fastest transatlantic (横渡大西洋的) rowing crossing, she only overturned once!

A man may usually be known by the books he reads as well as by the company he keeps; for there is a companionship of books as well as of men; and one should always live in the best company, whether it is of books or of men.

A good book may be among the best of friends. It is the most patient and cheerful companions. It does not turn its back upon us in times of adversity or distress. It always receives us with the same kindness, amusing and instructing us in youth, and comforting and consoling us in age.

There is an old proverb, "Love me, love my dog." But there is more wisdom in this: "Love me, love my book." The book is a truer and higher bond of union. Men can think, feel, and sympathize with each other through their favorite author. They live in him together, and he in them. The best books are treasuries of good words, the golden thoughts, which, remembered and cherished, become our constant companions and comforters.

Books possess an essence of immortality. They are by far the most lasting products of human effort. Temples and statues decay, but books survive. Time is of no account with great thoughts, which are as fresh today as when they first passed through their author's minds, ages ago. What was then said and thought still speaks to us as vividly as ever from the printed page. The only effect of time has been to sift out the bad products, for nothing in literature can long survive but what is really good.

Books introduce us into the best society; they bring us into the presence of the greatest minds that have ever lived. We hear what they said and did; we see them as if they were really alive; we sympathize with them, enjoy with them and grieve with them. The great and good do not die, even in this world. Embalmed in books, people's spirits walk abroad. The book is a living voice. It is an intellect to which one still listens.