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.

    Our brains work in complex and strange ways. There are some people who can calculate the day of the week for any given date in 40,000 years, but who cannot add two plus two. Others can perform complex classical piano pieces after hearing them once, but they cannot read or write.

    Dr. J. Langdon Down first described this condition in 1887. He called these people idiot savants. An idiot savant is a person who has significant mental injury, such as in autism (自闭症) or retardation. At the same time, the person also exhibits some extraordinary skills, which are unusual for most people. The skills of the savant may vary from being exceptionally gifted in music or in mathematics, or having a photographic memory. One of the first descriptions of a human who could calculate quickly was written in 1789 by Dr. Benjamin Rush, an American doctor. His patient, Thomas Fuller, was brought to Virginia as a slave in 1724. It took Thomas only 90 seconds to work out that a man who has lived 70 years, 17 days, and 12 hours has lived 2,210,500,800 seconds. Despite this ability, he died in 1790 without ever learning to read or write.

    Another idiot savant slave became famous as a pianist in the 1860s. Blind Tom had a vocabulary of only 100 words, but he played 5,000 musical pieces beautifully.

    In the excellent movie Rain Man, made in 1988 and available on video cassette, Dustin Hoffman plays an idiot savant who amazes his brother played by Tom Cruise, with his ability to perform complex calculations very rapidly.

Today we more clearly recognize that the idiot savant is special because of brain impairment. Yet not all brain injury leads to savant skills. Some studies have shown that people who have purposeful interruption of the left side of the brain can develop idiot savant skills. However few people wish to participate in such experiments. There are many excellent reasons for not undergoing unnecessary experimentation on one's brain. The term idiot savant is outdated and inappropriate. Virtually all savants have a high degree of intelligence and are thus not idiots.

    Should we allow modern buildings to be built next to older buildings in a historic area of a city? In order to answer this question, we must first examine whether people really want to preserve the historic feel of an area. Not all historical buildings are attractive. However, there may be other reasons—for example, economic (经济的) reasons—why they should be preserved. So, let us assume that historical buildings are both attractive and important to the majority of people. What should we do then if a new building is needed?

    In my view, new architectural styles can exist perfectly well alongside an older style. Indeed, there are many examples in my own home town of Tours where modern designs have been placed very successfully next to old buildings. As long as the building in question is pleasing and does not dominate (影响) its surroundings too much, it often improves the attractiveness of the area.

    It is true that there are examples of new buildings which have spoilt (破坏) the area they are in, but the same can be said of some old buildings too. Yet people still speak against new buildings in historic areas. I think this is simply because people are naturally conservative(保守的)and do not like change.

    Although we have to respect people's feelings as fellow users of the buildings, I believe that it is the duty of the architect and planner to move things forward. If we always reproduced what was there before, we would all still be living in caves. Thus, I would argue against copying previous architectural styles and choose something fresh and different, even though that might be the more risky choice.

    We all know that water is tasteless. But it happens from time to time: you pick up the bottle of water you didn't finish yesterday, and it tastes strange. Most often, you tend to drop the bottle in the trash bin, believing that the water has gone bad. But is it true?

    According to Time, of course not, taste has little to do with quality of water.

    According to Time, when water is exposed to the air for 12 hours, carbon dioxide interacts with the H2O in the water, and the pH value lowers slightly. As a result, the water has a different taste.

    "But it's most likely safe to drink," Norwegian expert Truls Krogh told Science Nordic. "If the water is covered and of good quality to start with, in principle it can last a thousand years. That's because when water is fresh, it contains little organic matter. As long as water is held in clean glasses or bottles, no pollutants will enter it to harm our health."

    People in countries like the US, the UK and Australia usually drink tap water. According to Time, if tap water is drunk within six months, the chlorine (氯气) in the water will be enough to kill any bacteria and keep it safe to drink.

    However, there are also some exceptions. If you accidentally put your fingers into water or store water in unclean containers day after day, microorganism (微生物) will enter the water.

    With the help of surrounding temperature, and sunlight streaming through windows, these microorganisms multiply quickly. Sooner or later, the water will be in the charge of the unfriendly bacteria. And if you drink the water too often, then you're more likely to be ill.

    And what about water in plastic bottles? Heat and plastic are a bad combination, US researcher Kellogg Schwab stresses. When plastic bottles are used at high temperatures, they produce a chemical called BPA. BPA is something that affects hormones (荷尔蒙) and research has tentatively linked it to "several health damage, including heart disease and cancer", Time reported.

    Schwab suggests replacing disposable (一次性的) plastic bottles with the refillable containers made of metal or glass to deal with BPA.

Fourteen-year-old Harini Logan won the Scripps National Spelling Bee last Thursday, defeating 12-year-old Vikram Raju in a tie-breaker. It's the first time the con test has ever been decided by a tie-breaking round of spelling.

A spelling bee is a contest where players take turns spelling words. Players who spell a word wrong are out of the contest. As the con test goes on, the words get more difficult. Normally, the contest ends when there's only one player left who hasn't made a mistake. Though the bee is mainly about spelling, since 2021 it has changed slightly to also focus on the meaning of the words. During parts of the contest, students were asked to choose the correct meaning of a word.

That caused trouble for Harini. She was asked about the meaning of the word "pullulation". She said the word described the nesting of birds. The con test organizers had expected the answer the "swarming of bees". Harini was removed from the contest. But soon she was back in—the judges double checked and learned that Harini's definition was also correct. One by one, the other students spelled a word wrong and got out. Finally, only Harini and Vikram were left.

The Scripps bee has been running for over 90 years. Many times it ended in a tie. As a result, the contest organizers changed the rules. They added a "spell-off" to the contest to make future ties much less likely. In the spell-off, Vikram and Harini each took turns trying to spell the words they were asked, but both made mistakes. At one point, Harini could have won by spelling the word "drimys"（a kind of plant）correctly. But she missed It.

That put the two into a super tie-breaking event, where they were each given 10 second s to correctly spell as many words as they could. In 90 seconds, Vikram had spelled 13 words correctly. Harini had 21 correct spellings, making her the new winner.

Whales are celebrated for being the largest and most intelligent creatures in the ocean. Now, biologists have discovered that they also capture（捕获） tons of carbon from the atmosphere, a service with an economic value of US $1 trillion for all the great whales, according to a new study published by the International Monetary Fund. The study points out that protecting whales, normally viewed as a human good, also has a monetary motivation.

"The carbon capture potential of whales is truly incredible," said the report. "Our conservative estimates put the value of the average great whale at more than US $2 million, and easily over US $1 trillion for the current stock of great whales." Whales absorb carbon in their bodies during their long lives, some of which stretch to 200 years. When they die, they sink to the bottom of the ocean, taking the carbon with them. According to the study, each great whale traps around 33 tons of carbon dioxide on average. A tree during the same period only contributes to 3percent of the carbon absorption of the whale.

Whale populations are today a smidgen of what they once were. It is estimated that there are slightly more than 1.3 million whales in the ocean, a quarter of their pre-whaling number of 4 t o5 million. Some species in particular, like the blue whale, are only 3 percent of what they used to be. "We can create financial methods to promote the restoration of the world's whale populations," said the report's authors. "Rewards could help those who pay significant costs as a result of whale protection."

With the Paris Agreement coming into force next year and the effects of climate change ever more widespread, we must prevent the harm to whales. Researchers analyzed that unless new methods are put forward, it would take over 30 years to double the number of current whales, and several generations to return them to their pre-whaling numbers. "Society and our own survival can't afford to wait this long," they said.