:: Reading :: IELTS For academic Purpose Reading 4

You should spend about 20 minutes on Questions 1-14, which are based on Reading Passage 1 below.

Prehistoric Cave Paintings Took up to 20,000 Years to Complete
It may have taken Michelangelo four long years to paint his fresco on the ceiling of the Sistine Chapel, but his earliest predecessors spent considerably longer perfecting their own masterpieces. Scientists have discovered that prehistoric cave paintings took up to 20,000 years to complete. Rather than being created in one session, as archaeologists previously thought, many of the works discovered across Europe were produced over hundreds of generations, who added to, refreshed and painted over the original pieces of art.

Until now it has been extremely difficult to pinpoint when prehistoric cave paintings and carvings were created, but a pioneering technique is allowing researchers to date cave art accurately for the first time and show how the works were crafted over thousands of years. Experts now hope the technique will provide a valuable insight into how early human culture developed and changed as the first modem humans moved across Europe around 40,000 years ago.

Dr Alistair Pike, an archaeologist at Bristol University who is leading the research, said: The art gives us a really intimate window into the minds of the individuals who produced it, but what we don’t know is exactly which individuals they were as we don’t know exactly when the art was created. If we can date the art then we can relate that to the artefacts we find in the ground and start to link the symbolic thoughts of these individuals to where, when and how they were living.’

Hundreds of caves have been discovered across Europe with elaborate prehistoric paintings and carvings on their walls. It is thought the designs, which often depict scenes of animals, were created up to 40,000 years ago – some time after humans began moving from southern Europe into northern Europe during the last ice age.

Traditional dating techniques have relied on carbon dating the charcoal and other pigment used in the paintings, but this can be inaccurate as it only gives the date the charcoal was created not when the work was crafted. ‘When you go into these caves today there is still charcoal lying on the ground, so the artists at the time could have been using old charcoal rather than making it fresh themselves/ explained Dr Pike.

‘If this was the case, then the date for the painting would be very wrong. Taking samples for carbon dating also means destroying a bit of these precious paintings because you need to take away a bit of the pigment. For carvings, it is virtually impossible to date them as there is no organic pigment containing carbon at all.’

The scientists have used their technique to date a series of famous Palaeolithic paintings in Altamira cave, northern Spain. Known as the ‘Sistine Chapel of the Palaeolithic’, the elaborate works were thought to date from around 14,000 years ago. But in research published by the Natural Environment Research Council’s new website Planet Earth, Dr Pike discovered some of the paintings were between 25,000 and 35,000 years old. The youngest paintings in the cave were 11,000 years old. Dr Pike said:’We have found that most of these caves were not painted in one go, but the painting spanned up to 20,000 years. This goes against what the archaeologists who excavated in the caves found. It is probably the case that people did not live in the caves they painted. It seems the caves they lived in were elsewhere and there was something special about the painted caves.’

Dr Pike and his team were able to date the paintings using a technique known as uranium series dating, which was originally developed by geologists to date rock formations such as stalactites and stalagmites in caves. As water seeps through a cave, it carries extremely low levels of dissolved radioactive uranium along with the mineral calcium carbonate. Overtime small amounts of calcium carbonate are deposited to form a hard layer over the paintings and this layer also traps the uranium. Due to its radioactive properties, the uranium slowly decays to become another element known as thorium. By comparing the ratio of uranium to thorium in the thin layers on top of the cave art, the researchers were able to calculate the age of the paintings.

The researchers have also applied their technique to engravings found in rocks around Creswell Crags in Derbyshire, which are Britain’s only examples of ice age cave art They proved the engravings were made at least 12,000 years ago. Professor Pablo Arias, an expert on Palaeolithic cave art at the University of Cantabria, Spain, said: ’Until about ten years ago it was only possible to date cave art by using the style of the figures, but this new technique developed by Bristol University allows that date to be accurately bracketed. We want to study how the people of the time behaved and how they felt and Palaeolithic art gives us a way of looking at the type of symbols that were important to them, so we need to know when the people who were making the art actually lived.’

You should spend about 20 minutes on Questions 15-27, which are based on Reading Passage 2 below.

Children Tested to Destruction? English primary school pupils subjected to more tests than in any other country. English primary school pupils have to deal with unprecedented levels of pressure as they face tests more frequently, at a younger age, and in more subjects than children from any other country, according to one of the biggest international education inquiries in decades. The damning indictment of England’s primary education system revealed that the country’s children are now the most tested in the world. From their very earliest days at school they must navigate a set-up whose trademark is ’high stakes’ testing, according to a recent report Parents are encouraged to choose schools for their children based on league tables of test scores. But this puts children under extreme pressure which could damage their motivation and self-esteem, as well as encouraging schools to ’teach to the test’ at the expense of pupils’ wider learning, the study found. The findings are part of a two-year inquiry – led by Cambridge University – into English primary schools. Other parts of the UK and countries such as France, Norway and Japan used testing but it was,’less intrusive, less comprehensive, and considerably less frequent’, Cambridge’s Primary Review concluded. England was unique in using testing to control what is taught in schools, to monitor teaching standards and to encourage parents to choose schools based on the results of the tests, according to Kathy Hall, from the National University of Ireland in Cork, and Kamil Ozerk, from the University of Oslo, who conducted the research. ‘Assessment in England, compared to our other reviewed countries, is pervasive, highly consequential, and taken by officialdom and the public more generally to portray objectively the actual quality of primary education in schools,’ their report concluded. Teachers’ leaders said the testing regime was ‘past its sell-by date’ and called for a fundamental review of assessment Steve Sinnott, General Secretary of the National Union of Teachers, said England’s testing system was having a ’devastating’ impact on schools.’Uniquely, England is a country where testing is used to police schools and control what is taught,’ he said.’When it comes to testing in England, the tail wags the dog. It is patently absurd that even the structure and content of education is shaped by the demands of the tests. I call on the Government to initiate a full and independent review of the impact of the current testing system on schools and on children’s learning and to be prepared to dismantle a system which is long past its sell-by date.’ John Dunford, General Secretary of the Association of School and College Leaders, warned that the tests were having a damaging effect on pupils. The whole testing regime is governed by the need to produce league tables,’ he said. ‘It has more to do with holding schools to account than helping pupils to progress.’ The fear that many children were suffering intolerable stress because of the tests was voiced by Mick Brookes, General Secretary of the National Association of Head Teachers. There are schools that start rehearsing for key stage two SATs [Standard Assessment Tests] from the moment the children arrive in September. That’s just utterly ridiculous/ he said. There are other schools that rehearse SATs during Christmas week. These are young children we are talking about. They should be having the time of their lives at school not just worrying about tests. It is the breadth and richness of the curriculum that suffers. The consequences for schools not reaching their targets are dire – heads can lose their jobs and schools can be closed down. With this at stake it’s not surprising that schools let the tests take over.’ David Laws, the Liberal Democrat schools spokesman, said 'The uniquely high stakes placed on national tests mean that many primary schools have become too exam focused.’ However, the Government rejected the criticism. The idea that children are over-tested is not a view that the Government accepts/a spokesman said. The reality is that children spend a very small percentage of their time in school being tested. Seeing that children leave school up to the right standard in the basics is the highest priority of the Government.’ In another child-centred initiative, both major political parties in the UK – Labour and the Conservatives – have announced plans to make Britain more child-friendly following a report by UNICEF which ranked the UK the worst place to be a child out of 21 rich nations. Parents were warned that they risked creating a generation of ’battery-farmed children’ by always keeping them indoors to ensure their safety. The family’s minister, Kevin Brennan, called for an end to the ’cotton wool’ culture and warned that children would not learn to cope with risks if they were never allowed to play outdoors.

You should spend about 20 minutes on Questions 28-40, which are based on Reading Passage 3 below.

Three ways to Levitate a Magic Carpet It sounds like a science fiction joke, but it isn’t. What do you get when you turn an invisibility cloak on its side? A mini flying carpet- So say physicists who believe the same exotic materials used to make cloaking devices could also be used to levitate tiny objects. In a further breakthrough, two other research groups have come a step closer to cracking the mysteries of levitation. Scientists have levitated objects before, most famously using powerful magnetic fields to levitate a frog. But that technique, using the repulsive force of a giant magnet, requires large amounts of energy. In contrast, the latest theories exploit the natural smaller amounts of energy produced by the quantum fluctuations of empty space. In May 2006, two research teams led by Ulf Leonhardt at St Andrew’s University, UK, and John Pendry at Imperial College, London, independently proposed that an invisibility cloak could be created from exotic materials with abnormal optical properties. Such a cloaking device – working in the microwave region – was manufactured later that year. The device was formed from so-called ‘metamaterials’, exotic materials made from complex arrays of metal units and wires.The metal units are smaller than the wavelength of light and so the materials can be engineered to precisely control how electromagnetic light waves travel around them. They can transform space, tricking electromagnetic waves into moving along directions they otherwise wouldn’t says Leonhardt. Leonhardt and his colleague Thomas Philbin, also at St Andrew’s University, realised that this property could also be exploited to levitate extremely small objects. They propose inserting a metamaterial between two so-called Casimir plates. When two such plates are brought very close together, the vacuum between them becomes filled with quantum fluctuations of the electromagnetic field. As two plates are brought closer together, fewer fluctuations can occur within the gap between them, but on the outer sides of the plates, the fluctuations are unconstrained. This causes a pressure difference on either side of the plates, forcing the plates to stick together, in a phenomenon called the Casimir effect. Leonhardt and Philbin believe that inserting a section of metamaterial between the plates will disrupt the quantum fluctuations of the electromagnetic field. In particular, metamaterials have a negative refractive index, so that electromagnetic light waves entering a metamaterial bend in the opposite way than expected, says Leonhardt. That will cause the Casimir force to act in the opposite direction – forcing the upper plate to levitate. The work will appear in the New Journal of Physics. Federico Capasso, an expert on the Casimir effect at Harvard University in Boston, is impressed.’Using metamaterials to reverse the Casimir effect is a very clever idea’ he says. However, he points out that because metamaterials are difficult to engineer, it’s unlikely that they could be used to levitate objects in the near future. But there are good signs that quantum levitation could be achieved much sooner, by other methods. Umar Mohideen at the University of California Riverside and his colleagues have successfully manipulated the strength of the Casimir force by increasing the reflectivity of one of the plates, so that it reflects virtual particles more efficiently. Modifying the strength of the Casimir force is the first step towards reversing it, says team member Galina Klimchitskaya at North-West Technical University in St Petersburg, Russia. Capasso and his colleagues have also been working on an alternative scheme to harness a repulsive Casimir effect Their calculations show that a repulsive Casimir force could be set up between a 42.7 micrometre-wide gold-coated polystyrene sphere and a silicon dioxide plate, if the two are immersed in ethanol. ‘Although the Casimir force between any two substances – the ethanol and gold, the gold and the silicon dioxide, or the silicon dioxide and the ethanol – is positive, the relative strengths of attraction are different, and when you combine the materials, you should see the gold sphere levitate’ he says. Capasso’s early experiments suggest that such repulsion could occur, and that in turn could be used to levitate one object above another. 'It’s very early work, and we still need to make certain this is really happening, but we are slowly building up experimental evidence for quantum levitation', says Capasso, who presented his results at a conference on Coherence and Quantum Optics in Rochester, New York, in June. 'This is a very exciting experimental result because it is the first demonstration that we can engineer a repulsive Casimir force', says Leonhardt.

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