Lockers(储物柜)have been the symbol of American high school for decades. But walk down any hallway of the new Germantown High School in Madison County, Mississippi, and you won't spot a single locker.

    New technology such as e-books, interactive(互动的)assignments and Web-based learning is making lockers in

    American high school a thing of the past.

    Officials from schools that have listed several benefits: less noise, less delay and an increased sense of safety.

    “It's all to create an environment that's student-friendly”, said Ronnie McGehee, chief official of the Madison County School District.

    Getting rid of lockers can also cut hundreds of thousands in construction costs. Madison County saved $200,000 by not including lockers in the new high school, McGehee said.

    It is also believed that removing lockers could help prevent school violence. ”Lockers give kids a place to hide things”, said Mike Nelson, founder of a safety- training group. Nelson believes that some school shootings and other incidents could have been prevented if there had been no lockers.

    However, Andrew Booth, a 10th-grader at Gemantown High, said there are some disadvantages of not having a locker. “It can make your book bag really heavy”, he said. The 16-year-old has four textbooks “plus notebooks and a binder(活页夹)” to carry to school each day.

    He said some teachers have shelves at the back of the classroom on which students can leave their bags. Others provide an extra set of textbooks in the classroom, so students don't have to carry books from home.

    New York architect Peter Lippman said schools will have to address such concerns and find ways to give students a “sense of space” “If you are carrying books around, it does limit your flexibility in the classrooms,” he said.

Lippman said he would like to see schools starting to use the new free space to provide less structured learning opportunities for students, including gathering areas and learning centers. “If you think about a school with just rows of lockers-there's nowhere for learning opportunities in that”, he said.

    Crown shyness (树冠羞避) is a mysterious natural phenomenon in which the crowns of some tree species do not touch each other, but get separated by a gap clearly seen from ground level. The effect usually occurs between trees of the same species, but has also been observed between trees of different species.

    There are many theories going around, most of which make sense, but no one has been able to prove without the shadow of a doubt why some trees avoid touching each other.

    In his 1955 book Growth Habits of the Eucalypts, Australian forester M. R. Jacobs writes that the growing tips of the trees are sensitive to abrasion (擦伤), which results in crown shyness phenomenon. This theory was also supported by Dr. Miguel Franco. Some experiments have shown that if trees displaying crown shyness are artificially prevented from swaying (摇摆)in the wind and touching each other, they gradually fill up the gaps between them.

    But while the above theory is arguably the most widespread, it's certainly not the only one. Some scientists have suggested that crown shyness is a mechanism to stop the spreading of leaf-eating insects. The gaps mean pests wouldn't be able to reach other trees, so they are the tree's natural defense method.

    One Malaysian scholar studied many trees, but found no traces of abrasions, despite their clear crown shyness. Instead, he suggests that the growing tips of the trees were sensitive to light levels and stopped growing when they got too close to other trees. Plants are able to sense how close they are to other plants and in order to get more light, they give off some chemical to stop other trees from growing too close.

    Whatever the reason, one thing is for sure, plants are more intelligent than people.

    Almost every machine with moving parts has wheels, yet no one knows exactly when the first wheel was invented or what it was used for. We do know, however, that they existed over 5,500 years ago in ancient Asia.

    The oldest known transport wheel was discovered in 2002 in Slovenia. It is over 5,100 years old. Evidence suggests that wheels for transport didn't become popular for a while, though. This could be because animals did a perfectly good job of carrying farming tools and humans around.

    But it could also be because of a difficult situation. While wheels need to roll on smooth surfaces, roads with smooth surfaces weren't going to be constructed until there was plenty of demand for them. Eventually, road surfaces did become smoother, but this difficult situation appeared again a few centuries later. There had been no important changes in wheel and vehicle design before the arrival of modem road design.

    In the mid-1700s, a Frenchman came up with a new design of road—a base layer (层) of large stones covered with a thin layer of smaller stones. A Scotsman improved on this design in the 1820s and a strong, lasting road surface became a reality. At around the same time, metal hubs (the central part of a wheel) came into being, followed by the pneumatic tyre (充气轮胎) in 1846. Alloy wheels were invented in 1967, sixty years after the appearance of tarmacked roads (柏油路). As wheel design took off, vehicles got faster and faster.

    Anyone watching the autumn sky knows that migrating birds fly in a V formation, but scientists have long debated why. A new study finds that these big－winged birds carefully position their wingtips and flap(拍动) at the same rate, probably to catch the upward movement of air and save energy during flight.

    There are two reasons birds might fly in a V formation: It may make flight easier, or they're simply following the leader. Squadrons(中 队) of planes can save fuel by flying in a V formation, and many scientists suspect that migrating birds do the same. Models that treated flapping birds like fixed－wing airplanes show that they probably save energy by drafting off each other, but currents created by airplanes are far more stable than those coming off of birds.

    Just as aerodynamic(气动力) calculations would predict, the birds positioned themselves to fly just behind and to the side of the bird in front, timing their wing flaps to catch the uplifting eddies(涡流). When a bird flew directly behind another, the timing of the flapping reversed(相反) so that it could minimize the effects of the downdraft coming off the back of the bird's body. “We didn't think this was possible,” Usherwood says, considering that the difficult achievement requires careful flight and incredible awareness of one's neighbors. “Perhaps these big V formation birds can be thought of quite like an airplane with wings that go up and down.”

    The findings likely apply to other long－winged birds, such as pelicans and geese, Usherwood says. Smaller birds create more complex wakes(尾波) that would make drafting too difficult. The researchers did not attempt to calculate the birds' energy savings because the necessary physiological measurements would be too invasive for an endangered species. Previous studies show that birds can use 20% to 30% less energy while flying in a V.

    Scientists do not know how the birds find that aerodynamic sweet spot, but they suspect that the animals line themselves up either by sight or by sensing air currents through their feathers. In future studies, the researchers will switch to more common birds, such as pigeons or geese. They plan to investigate how the animals decide who sets the course and the pace, and whether a mistake made by the leader can ripple through the rest of the flock to cause traffic jams.

Even though they're not the most exciting things in the world, plants have fascinated us ever since the days of early humans. They may not do any tricks or greet us when we come home at night like a dog would, but that doesn't mean they're any less interesting than animals.

However, just when we thought we knew everything we could about them, a recent study found that plants may possess a secret ability that's gone unnoticed all this time. According to the study by Australian biologist Monica Gagliano, published in the journal Oecologia, plants may be able to hear sounds.

To come to this conclusion, Gagliano and her team planted pea seedlings in a pair of different Y-shaped pots with two arms. The first pot's arms led to fresh water, while the other's led to either dry soil or a sealed plastic tube containing flowing water.

Naturally, the first pot's seedlings grew toward the water. What's surprising, however, is that the second pot's seedlings grew toward the sealed water supply and not the soil.

They just knew the water was there, even if the only thing to detect was the sound of it flowing inside the pipe, Gagliano told Scientific American. Gagliano believes that plants are able to use their leaves to detect sound waves, which make tiny vibrations (振动) as they're produced.

This could explain why so many people believe that singing or playing music to their plants helps them grow.

I had a plant that I used to wash the leaves once a week and sing to it, plant lover Heather Goodall told BBC News. It grew from being about 2 feet tall to 7 feet tall in just a couple of years.

So, does this mean we should start treating our plants like pets? Not necessarily, although perhaps it does mean we should give them more respect. I would like to see plants acknowledged more as the amazing, interesting, exotic living beings they are, and less as a mere source of human nutrition, Fatima Cvrckova, a scientist at Charles University in the Czech Republic, told BBC News.

Would you drink water that had once been flushed down a toilet? After it's been cleaned, that is. The climate is warming, and the population of drought-prone states California continues to grow. So recycling wastewater into drinking water may become a necessity.

But, it can be really hard for people to get over their disgust at the thought of drinking recycled water. People are grossed out by cycled water, because it was once wastewater—you know, the stuff that goes down your kitchen drains, your showers, your toilets. And even though it's cleaned up to a standard that is identical, if not better, than commercially bottled water, the key barrier to recycled water acceptance is people's disgust regarding it, " said Daniel Harmon, a psychologist in University of California.

In one experiment, the researchers had some participants watch a short video promoting water conservation. And in another experiment, they added a video explaining why recycled water might trigger disgust even though all pollutants have been removed. And neither video had a strong effect on people's willingness to drink recycled water or to support the practice.

The messages were not enough to get them to actually use recycled water more. "Disgust is such a powerful reaction that simply giving more information is not going to really be effective. " The study appears in the journal Basic and Applied Social Psychology.

Researchers say it's probably going to take a lot more to get people to embrace recycled water. For example, it might help to see members of their community drinking water that's gone, as it's called, from "toilet to tap, " with no ill effects.

It is clear that these kinds of more direct campaigns for acceptance are necessary to get people to get over that psychological barrier—to take that first sip, so to speak. Cheers!