Jimmy Wales' Wikipedia comes close to Britannica in terms of the accuracy of its science entries, a Nature investigation finds.

One of the extraordinary stories of the Internet age is that of Wikipedia, a free online encyclopaedia that anyone can edit. This radical and rapidly growing publication, which includes close to 4 million entries, is now a much-used resource. But it is also controversial: if anyone can edit entries, how do users know if Wikipedia is as accurate as established sources such as Encyclopaedia Britannica?

AP PHOTO/M. PROBST

Several recent cases have highlighted the potential problems. One article was revealed as falsely suggesting that a former assistant to US Senator Robert Kennedy may have been involved in his assassination. And podcasting pioneer Adam Curry has been accused of editing the entry on podcasting to remove references to competitors' work. Curry says he merely thought he was making the entry more accurate.

However, an expert-led investigation carried out by Nature the first to use peer review to compare Wikipedia and Britannica's coverage of science suggests that such high-profile examples are the exception rather than the rule.

The exercise revealed numerous errors in both encyclopaedias, but among 42 entries tested, the difference in accuracy was not particularly great: the average science entry in Wikipedia contained around four inaccuracies; Britannica, about three.

Considering how Wikipedia articles are written, that result might seem surprising. A solar physicist could, for example, work on the entry on the Sun, but would have the same status as a contributor without an academic background. Disputes about content are usually resolved by discussion among users.

But Jimmy Wales, co-founder of Wikipedia and president of the encyclopaedia's parent organization, the Wikimedia Foundation of St Petersburg, Florida, says the finding shows the potential of Wikipedia. "I'm pleased," he says. "Our goal is to get to Britannica quality, or better."

Wikipedia is growing fast. The encyclopaedia has added 3.7 million articles in 200 languages since it was founded in 2001. The English version has more than 45,000 registered users, and added about 1,500 new articles every day of October 2005. Wikipedia has become the 37th most visited website, according to Alexa, a web ranking service.

But critics have raised concerns about the site's increasing influence, questioning whether multiple, unpaid editors can match paid professionals for accuracy. Writing in the online magazine TCS last year, former Britannica editor Robert McHenry declared one Wikipedia entry on US founding father Alexander Hamilton as "what might be expected of a high-school student". Opening up the editing process to all, regardless of expertise, means that reliability can never be ensured, he concluded.

Yet Nature's investigation suggests that Britannica's advantage may not be great, at least when it comes to science entries. In the study, entries were chosen from the websites of Wikipedia and Encyclopaedia Britannica on a broad range of scientific disciplines and sent to a relevant expert for peer review. Each reviewer examined the entry on a single subject from the two encyclopaedias; they were not told which article came from which encyclopaedia. A total of 42 usable reviews were returned out of 50 sent out, and were then examined by Nature's news team.

Only eight serious errors, such as misinterpretations of important concepts, were detected in the pairs of articles reviewed, four from each encyclopaedia. But reviewers also found many factual errors, omissions or misleading statements: 162 and 123 in Wikipedia and Britannica, respectively.

D. I. FRANKE/WIKIMEDIA FDN

Kurt Jansson (left), president of Wikimedia Deutschland, displays a list of 10,000 Wikipedia authors; Wikipedia's entry on global warming has been a source of contention for its contributors.

Editors at Britannica would not discuss the findings, but say their own studies of Wikipedia have uncovered numerous flaws. "We have nothing against Wikipedia," says Tom Panelas, director of corporate communications at the company's headquarters in Chicago. "But it is not the case that errors creep in on an occasional basis or that a couple of articles are poorly written. There are lots of articles in that condition. They need a good editor."

Several Nature reviewers agreed with Panelas' point on readability, commenting that the Wikipedia article they reviewed was poorly structured and confusing. This criticism is common among information scientists, who also point to other problems with article quality, such as undue prominence given to controversial scientific theories. But Michael Twidale, an information scientist at the University of Illinois at Urbana-Champaign, says that Wikipedia's strongest suit is the speed at which it can updated, a factor not considered by Nature's reviewers.

"People will find it shocking to see how many errors there are in Britannica," Twidale adds. "Print encyclopaedias are often set up as the gold standards of information quality against which the failings of faster or cheaper resources can be compared. These findings remind us that we have an 18-carat standard, not a 24-carat one."

The most error-strewn article, that on Dmitry Mendeleev, co-creator of the periodic table, illustrates this. Michael Gordin, a science historian at Princeton University who wrote a 2004 book on Mendeleev, identified 19 errors in Wikipedia and 8 in Britannica. These range from minor mistakes, such as describing Mendeleev as the 14th child in his family when he was the 13th, to more significant inaccuracies. Wikipedia, for example, incorrectly describes how Mendeleev's work relates to that of British chemist John Dalton. "Who wrote this stuff?" asked another reviewer. "Do they bother to check with experts?"

But to improve Wikipedia, Wales is not so much interested in checking articles with experts as getting them to write the articles in the first place.

As well as comparing the two encyclopaedias, Nature surveyed more than 1,000 Nature authors and found that although more than 70% had heard of Wikipedia and 17% of those consulted it on a weekly basis, less than 10% help to update it. The steady trickle of scientists who have contributed to articles describe the experience as rewarding, if occasionally frustrating (see 'Challenges of being a Wikipedian').

Greater involvement by scientists would lead to a "multiplier effect", says Wales. Most entries are edited by enthusiasts, and the addition of a researcher can boost article quality hugely. "Experts can help write specifics in a nuanced way," he says.

Wales also plans to introduce a 'stable' version of each entry. Once an article reaches a specific quality threshold it will be tagged as stable. Further edits will be made to a separate 'live' version that would replace the stable version when deemed to be a significant improvement. One method for determining that threshold, where users rate article quality, will be trialled early next year.

Additional research by Declan Butler, Jenny Hogan, Michael Hopkin, Mark Peplow and Tom Simonite.

But instead of celebrating, physicists are in mourning after a report showed a dramatic decline in the number of pupils studying physics at school. The number taking A-level physics has dropped by 38% over the past 15 years, a catastrophic meltdown that is set to continue over the next few years. The report warns that a shortage of physics teachers and a lack of interest from pupils could mean the end of physics in state schools. Thereafter, physics would be restricted to only those students who could afford to go to posh schools.

Britain was the home of Isaac Newton, Michael Faraday and Paul Dirac, and Brits made world-class contributions to understanding gravity, quantum physics and electromagnetism - and yet the British physicist is now facing extinction. But so what? Physicists are not as cuddly as pandas, so who cares if we disappear?

You should care, and this is why. First, physicists reveal the beauty of the universe. E=mc2 provides us with an incredible insight into how the universe works, showing us that energy (E) and mass (m) can be converted into each other, so that a tiny amount of mass can be destroyed to create a vast amount of energy. That is how the Sun shines. Four million tonnes of the Sun literally vanishes every second, only to reappear in the form of sunshine - energy that lights up our lives.

John Keats talked of "unweaving the rainbow", suggesting that Newton destroyed the beauty of nature by analysing light with a prism and splitting it into different colours. Keats was being a prat. Physicists also smile when we see rainbows, but our emotional reaction is doubled by our understanding of the deep physics relating to the prismatic effects of raindrops. Similarly, physicists appreciate sunsets more than anybody else, because we can enjoy the myriad colours and at the same time grasp the nuclear physics that created the energy that created the photons that travelled for millions of years to the surface of the Sun, which then travelled eight minutes through space to Earth, which were then scattered by the atmosphere to create the colourful sunset. Understanding physics only enhances the beauty of nature.

If you want a concrete return, then physics can deliver that too. E=mc2 underpins the nuclear power industry, which could provide more energy in the future. If nuclear power replaced fossil fuels, we would pump less carbon into the atmosphere and thereby halt global warming. If, instead, you want clean energy via solar cells or wind turbines, then an understanding of solid state physics or the physics of fluids will get you several steps closer to an economically viable solution. Either way, physics provides the best hope of saving the planet.

Also, it should not be forgotten that A-level physicists have a direct impact on the economy, because some of us become the inventors, innovators and engineers that create high-quality jobs and major exports. The people behind Google and Microsoft and Apple did physics at high school, as opposed to majoring in psychology or media studies.

So, without British physicists, our country will not win any more Nobel prizes in physics, we will not do our part in fixing global warming - and UK plc will go down the drain. And yet nobody in power really cares. Physics in British schools has been going downhill for a couple of decades, but both Labour and Conservative governments seem to have taken no notice. After all, nobody is going to die because A-level physics is going out of fashion. There are no photo opportunities in being seen with a physicist.

Personally, the desperate state of British physics education was brought home to me when I reflected on why my parents migrated to this country in 1950. They came here so that their children had the guarantee of a good education. However, today India produces more mathematicians than the whole of the European Union.

A budding boffin in Bangalore probably stands more chance of having good mathematics and physics teachers than the equivalent bright young spark condemned to a British science education. A British politician in 1950 would have laughed at the thought of Indian schools ever being better than British schools, but last year's Physics Olympiad shows how things have changed. In this international competition for schools students, India won two gold medals, two silvers and a bronze, whereas Britain won only two bronzes.

With Britain's negligent attitude to physics education, we do not deserve to be celebrating the centenary of Einstein's annus mirabilis. Instead, perhaps we should be marking 2005 as the 50th anniversary of his death, which would be in keeping with the moribund status of A-level physics

· Simon Singh has a PhD in particle physics. He is the author of Big Bang, a history of cosmology.

Do you know your Newton from your neutrons?

1. A metal plate is heated to 200C with a bunsen burner. It subsequently cools by emitting what kind of radiation?
a) Ultraviolet waves b) Gamma rays c) Infrared rays d) Radio waves

2. You're in the back of a stationary car with a helium balloon. When the car accelerates, which way does the balloon move?
a) Forwards b) Backwards c) Up d) It doesn't move

3. What two properties of a particle does Heisenberg's uncertainty principle say you can't measure at the same time?
a) Energy and mass b) Position and momentum c) Position and mass d) Momentum and velocity

4. A skater is spinning on a spot with her arms outstretched. What happens when she pulls her arms in?
a) Nothing b) She changes direction c) She spins more slowly d) She spins more quickly

5. A big wooden ball and a small ball bearing sit at the top of a slope. When they are released, which reaches the bottom first?
a) The wooden ball b) The ball bearing c) They both get there at the same time d) Depends on the masses of the balls and the angle of the slope

6. If the Sun were to disappear right now, how long would it be before we noticed?
a) Straight away b) About 8 minutes c) Just over an hour d) Almost a day

· Answers: 1c, 2a, 3b, 4d, 5c, 6b Alok Jha

CHILDREN should be seen and not heard" may be due for a comeback. After decades of indulgence, American society seems to have reached some kind of tipping point, as far as tolerance for wild and woolly kid behavior is concerned.

Last month, an Associated Press-Ipsos poll found that nearly 70 percent of Americans said they believed that people are ruder now than they were 20 or 30 years ago, and that children are among the worst offenders. (As annoyances, they tied with obnoxious cellphone users.)

The conservative child psychologist John Rosemond recently denounced in his syndicated column the increasing presence of "disruptive urchins" who "obviously have yet to have been taught the basic rudiments of public behavior," as he related the wretched experience of dining in a four-star restaurant in the company of one child roller skating around his table and another watching a movie on a portable DVD player.

In 2002, only 9 percent of adults were able to say that the children they saw in public were "respectful toward adults," according to surveys done then by Public Agenda, a nonpartisan and nonprofit public opinion research group. In 2004, more than one in three teachers told Public Agenda pollsters they had seriously considered leaving their profession or knew a colleague who had left because of "intolerable" student behavior.

Even Madonna - her "Papa Don't Preach" years long past - has joined the throng, proclaiming herself a proud "disciplinarian" in a recent issue of the British magazine Harpers & Queen and bragging that, as a mom, she takes a tough line on homework, tidiness and chores: "If you leave your clothes on the floor, they're gone when you come home."

Jo Frost, ABC's superstar "Supernanny," would be proud.

Whether children are actually any worse behaved now than they ever have been before is, of course, debatable. Children have always been considered, basically, savages. The question, from the late 17th century onwards, has been whether they come by it naturally or are shaped by the brutality of society.

But what seems to have changed recently, according to childrearing experts, is parental behavior - particularly among the most status-conscious and ambitious - along with the kinds of behavior parents expect from their kids. The pressure to do well is up. The demand to do good is down, way down, particularly if it's the kind of do-gooding that doesn't show up on a college application.

Once upon a time, parenting was largely about training children to take their proper place in their community, which, in large measure, meant learning to play by the rules and cooperate, said Alvin Rosenfeld, a child psychiatrist and co-author, with Nicole Wise, of "The OverScheduled Child: Avoiding the Hyperparenting Trap."

"There was a time when there was a certain code of conduct by which you viewed the character of a person," he said, "and you needed that code of conduct to have your place in the community."

Rude behavior, particularly toward adults, was something for which children had to be chastised, even punished. That has also now changed, said Dan Kindlon, a Harvard University child psychologist and author of "Too Much of a Good Thing: Raising Children of Character in an Indulgent Age."

Most parents, Dr. Kindlon said, would like their children to be polite, considerate and well behaved. But they're too tired, worn down by work and personally needy to take up the task of teaching them proper behavior at home.

"We use kids like Prozac," he said. "People don't necessarily feel great about their spouse or their job but the kids are the bright spot in their day. They don't want to muck up that one moment by getting yelled at. They don't want to hurt. They don't want to feel bad. They want to get satisfaction from their kids. They're so precious to us - maybe more than to any generation previously. What gets thrown out the window is limits. It's a lot easier to pick their towel up off the floor than to get them away from the PlayStation to do it."

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Parenting today is also largely about training children to compete - in school and on the soccer field - and the kinds of attributes they need to be competitive are precisely those that help break down society's civility.

Parents who want their children to succeed more than anything, Dr. Kindlon said, teach them to value and prioritize achievement above all else - including other people.

"We're insane about achievement," he said. "Schoolwork is up 50 percent since 1981, and we're so obsessed with our kids getting into the right school, getting the right grades, we let a lot of things slide. Kids don't do chores at home anymore because there isn't time."

And other adults, even those who should have authority, are afraid to get involved. "Nobody feels entitled to discipline other people's kids anymore," Dr. Kindlon said. "They don't feel they have the right if they see a kid doing something wrong to step in."

Educators feel helpless, too: Nearly 8 in 10 teachers, according to the 2004 Public Agenda report, said their students were quick to remind them that they had rights or that their parents could sue if they were too harshly disciplined. More than half said they ended up being soft on discipline "because they can't count on parents or schools to support them."

And that, Dr. Rosenfeld said, strikes at the heart of the problem. "Parents are out of control," he said. "We always want to blame the kids, but if there's something wrong with their incivility, it's the way their parents model for them."

There's also the chance, said Wendy Mogel, a clinical psychologist whose 2001 book, "The Blessing of a Skinned Knee," has earned her a cult following, that when children are rude, obnoxious and outrageously behaved, they're trying to tell parents something - something they've got to shout in order for them to hear.

"These kids are so extremely stressed from the academic load they're carrying and how cloistered they are and how they have to live under the watchful eye of their parents," Dr. Mogel said. "They have no kid space."

Paradoxically, she said, parental over-involvement in their children's lives today often hides a very basic kind of indifference to their children's real need, simply to be kids. "There are all these blurry boundaries," she said. "They need to do fifth-grade-level math in third grade and have every pleasure and indulgence of adulthood in childhood and they act like kids and we get mad."

If stress and strain, self-centeredness and competition are the pathogens underlying the rash of rudeness perceived to be endemic among children in America today, then the cure, some experts said, has to be systemic and not topical. Stop blaming the children, they said. Stop focusing on the surface level of behavior and start curing instead the social, educational and parental ills that feed it.

This may mean less "quality" time with children and more time getting them to do things they don't want to do, like sitting for meals, making polite conversation and - Madonna was right - picking their clothes up off the floor.

Judith Warner is the author, most recently, of "Perfect Madness: Motherhood in the Age of Anxiety." She is also the host of "The Judith Warner Show" on XM satellite radio.