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Fun School Projects with Magnets and Metal
Science is one of the most interesting and fun subjects for kids.
There are endless opportunities for practical experiments that are sure to surprise and excite children's imaginations. A great way to get into experimenting with science is with the use of magnets. The properties of magnets allow for an “ invisible force ” to move objects seemingly on their own!
If your kids are looking for something a little trickier, why not let them try using magnets to make their own compass (指南针)？
For this experiment, you will need 2 needles, a strong magnet, a pencil, a cup and some string.
Step 1: Rub the pointed end of the needle along one side of the magnet ；this can be either the north or south end. Make sure you are rubbing the needle in one direction, not back and forth. You might need to do this about 30 times to magnetise the needle.
Step 2: Test the now magnetised needle with the spare needle to see if it can pick it up. If it can, the needle is ready to use for the experiment. If it doesn't pick it up, you will need to rub the needle a few more times on the same end of the magnet you were using before.
Step 3 : With a piece of string that is a couple of inches long, get your child to tie this to the middle of the pencil. Then, at the bottom end of the hanging string, tie the magnetised needle.
Step 4: Place the pencil, with the needle hanging down, over the top of a cup so that the needle is hanging inside the cup.
Step 5 : Watch as the needle moves on its own to point north.
Once your kids have got a taste for magnets, you might want to move on to more advanced experiments. Places like RS Components sell high-tech magnetic equipment that will be sure to carry on fuelling your children's passion for science!
1.According to the passage, the spare needle is used to _______.
A.pick the other needle up B.magnetise the other needle
C.rub the magnet on the other side D.check if the other needle is magnetised
2.The magnetised needle can point north because _______.
A.it is tied to a hanging string B.it has the properties of a magnet
C.it is connected with a magnet D.it is hanging down inside the cup
3.What is the main purpose of this passage?
A.To promote high-tech magnetic equipment.
B.To entertain kids with magnet experiments.
C.To stress the importance of advanced experiments.
D.To provide a way to fuel kids' passion for science.
难度: 中等查看答案及解析
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The Wolf at the Door
Russ Fee was asleep inside his tent last summer when a series of screams shocked him awake. Throwing on his shoes, he ran out to investigate. Fee and his wife were travelling through Canada's Banff National Park to enjoy its breathtaking beauty and awesome wildlife. It was the latter he now experienced. Although it was dark, Fee could see a neighboring tent was in a mess. Backing out was a wolf, dragging something in his teeth. That thing was a man J
Moments earlier, Elisa and Matt Rispoli, from New Jersey, were asleep with their two young children when the wolf broke into their tent. "It was like something out of a horror movie，'‘ Elisa posted on Facebook. "For three minutes, Matt threw his body in front of me and the boys and fought against the wolf. At one point, Matt got the upper hand, pinning (压住) the wolf to the ground. But the wolf held its jaw onto Matt's arm tightly, set its powerful legs, and began dragging Matt outside while I was pulling on his legs trying to get him back，'‘ Elisa wrote.
It was then that Fee entered the picture. He ran at the wolf, kicking it “like I was kicking in a door,” he told ABC New York. The wolf dropped Matt and emerged from the tent. "Wolves are large，'‘ Fee told the radio show Calgary Eyeopener. " I felt like I had hit someone that was way out of my weight class."
Before the wolf could turn its anger on Fee, Matt, his arms bloodied, flew out of the tent to continue the battle. The men threw rocks at the wolf, forcing it back, then the Fees and the Rispolis escaped to the shelter of the Fees’ minivan(厢式旅行车). An ambulance was called, and Matt was taken to a local hospital suffering from open wounds. Luckily he has fully recovered. The wolf was tracked down by park officials and killed in a painless way.
As for Fee, whom Elisa called their lifesaver, he does admit to a fleeting(闪现的),if less- than-heroic, thought during the heat of battle. The moment the wolf locked eyes with him, Fee says, "I immediately regretted kicking it."
1.What happened to the Rispolis one night last summer?
A.They were scared by a horror movie.
B.They were suddenly woken up by screams.
C.They got injured and taken to the hospital.
D.They suffered a surprise attack from a wolf
2.Russ Fee joined Matt Rispoli when _______.
A.Matt was dropped down by the wolf
B.Matt gained the advantage over the wolf
C.the wolf was dragging Matt out of the tent
D.the wolf broke into the tent of the Rispolis
3.Matt Rispoli survived because _______.
A.the wolf was killed by park officials B.he took shelter in a neighboring tent
C.he got great help and timely treatment D.the wolf was driven away by Russ Fee
4.What can we learn about Russ Fee from the last paragraph?
A.He feels regretful for what he did. B.He enjoys being called a lifesaver.
C.He feels quite heroic about himself D.He admits his fear during the fight.
难度: 中等查看答案及解析
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In autumn of 1975, two mothers in Lyme, Connecticut, were desperate for answers their doctors could not provide. Their families and others in the Lyme area were suffering from a mysterious(神秘的)illness. Two doctors from Yale, Allan Steere and Stephen Malawista, began an investigation that would result in a groundbreaking medical discovery.
The doctors began by conducting individual examinations of each patient. They found patients of all ages were suffering from a set of symptoms (症状) rarely observed together. Blood samples revealed no virus that offered a clue about the cause. However, they found fruitful information in their interviews with patients: one quarter of them recalled a skin rash (皮疹) with a bull’s-eye pattern about four weeks before other symptoms arose.
Armed with this new clue, the Department of Health worked with the Yale doctors, conducting surveys to learn where the disease was most widely seen. It seemed that the majority of patients lived in heavily wooded areas, who spent a good deal of time outdoors, gardening, landscaping, or playing. The symptoms were nearly always experienced for the first time during summer. Crucially, some recalled having been bitten by a tick (蝉), which feeds mostly on the blood of mammals and birds.
By 1977, investigators confirmed that the deer tick was responsible. But no one could say why it was causing the illness or how patients could be treated. In 1982, a scientist named Willy Burgdorfer discovered a specific type of bacteria (细菌), carried by the deer tick, which was causing the disease. But how did the deer tick acquire the bacteria in the first place? Finally, scientists determined that the ticks picked up the bacteria from their hosts. As its name suggests, the deer tick often feeds on deer, carriers of the Lyme disease bacteria. Scientists concluded that the bacteria passed from wildlife to ticks to humans. All lived closely among one another in the area.
How could a disease from a common parasite（寄生虫）spring up so suddenly? Many areas of the northeast, including Lyme, were once farmland. The farmland was replanted with trees. After the forest grew in, the area was then developed with houses. Gradually, neighborhoods pushed deeper into the habitat of deer ticks and, more importantly, the wildlife they fed upon. As humans encountered more ticks, they became more likely to contract the disease.
One of the remaining mysteries about Lyme disease is where and when it truly began. This puzzle may never be solved. Today, Lyme disease——if caught early—is easily treated with antibiotics, thanks to the hard work of many scientists, doctors, and patients.
1.Which of the following method helped Dr. Steere and Dr. Malawista most?
A.Conducting patient interviews. B.Carrying out a field survey.
C.Studying patients’ blood samples. D.Separating patients into age groups.
2.From the passage, we can learn that _______.
A.deer ticks were first carriers of the Lyme disease bacteria
B.patients’ remembrance of tick bites was vital to the medical discovery
C.Lyme disease spread because deer ticks and humans both fed on deer
D.Lyme disease is less common now because people spend less time outdoors
3.What do the underlined words “spring up” in Paragraph 5 probably mean?
A.Worsen. B.Return.
C.Appear. D.Decrease.
4.Which of the following would be the best tide for the passage?
A.A Desperate Need B.An Unsolved Puzzle
C.A Medical Mystery D.An Effective Treatment
难度: 困难查看答案及解析
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If there’s one cliche（陈词滥调）that really annoys Danah Boyd, a specialist researcher who has made a career from studying the way teenagers use the web, it’s that of the digital native. “Today the world has computer-mediated communications. Thus, in order to learn about their social world around them, teenagers are learning about those things too. And they’re using that to work out the stuff that kids have always worked out： peer（同龄人）sociality, status, etc.” she says.
It’s no surprise Boyd takes exception, really. As one of the first digital anthropologists to dig into the way teenagers use social networking sites, she gained insights into the social web by taking a closer look at what was going on.
Lately, her work has been about explaining new ways of interpreting the behavior we see online. She outlined some examples at a recent conference in San Francisco, including the case of a young man from one of the poorest districts of Los Angeles who was applying for a top American college. The applicant said he wanted to escape the influence of violence, but the admissions officer was shocked when he discovered that the boy's MySpace page was covered with precisely the violent language he claimed to hate. “Why was he lying about his motivations?” asked the university. “He wasn't, ” said Boyd. “In his world, showing the right images online was a key part of surviving daily life.”
Understanding what’s happening online is especially important, for today’s teenagers have a vastly different approach to privacy from their parents. She says, “Adults think of the home as a very private space. That’s often not the case for teenagers because they have little or no control over who has access to it, or under what conditions. As a result, the online world can feel more private because it feels like there's more control.”
The concept of control is central to Boyd's work, and it applies to pointing out the true facts about teenage behavior. Boyd suggests control remains in the same places as it always did.
“Technologists all go for the idea of techno・utopia （乌托邦）, the web as great democratizer （民主 化）”，she says. “But we’re not actually democratizing the whole system； we’re just shifting the way in which we discriminate.”
It’s a call to arms that most academic researchers would tend to sidestep, but then Boyd admits to treading a fine line between academics and activists. “The questions I continue to want to ask are the things that are challenging to me；having to sit down and be forced to think about uncomfortable social stuff, and it’s really hard to get my head around it, which means it’s exactly what I should dive in and deal with, ” she says.
1.What does Danah Boyd think of “computer-mediated communications”?
A.They teach teenagers about social interaction.
B.They replace other sorts of social interaction for teenagers.
C.They are necessary for teenagers to have social interaction.
D.They are barriers to wider social interaction among teenagers.
2.Why does Danah Boyd cite the example of the Los Angeles college applicant?
A.To show how easy it is to investigate somebody's online activity.
B.To illustrate how easy it is to misinterpret an individual online activity.
C.To prove how important it is to check the content of someone's online activity.
D.To express how necessary it is to judge someone's sincerity from his online activity.
3.Danah Boyd argues in Paragraph 4 that _______.
A.teenagers feel more private in the online world than in the home
B.teenagers are less concerned about privacy than their parents
C.parents tend not to respect teenagers'
need for online privacyD.parents value the idea of privacy less in a domestic environment
4.It can be inferred from the last paragraph that Danah Boyd _______.
A.is willing to take on research challenges others would avoid
B.regards herself as being more of an activist than a researcher
C.is aware that she is lacking in ability to deal with the challenges
D.feels like abandoning the research into uncomfortable social stuff
难度: 困难查看答案及解析
