IELTS Academic Reading Practice Test 13

Natural rubber begins as latex, a milky white fluid found beneath the bark of a number of tropical plants. Its function in the plant appears to be defensive: when the bark is damaged, latex flows out, seals the wound and can trap or deter insects. The most productive source by far is Hevea brasiliensis, a tree native to the Amazon basin, which can be tapped repeatedly for decades without being killed. When a thin, sloping groove is cut into its bark, latex oozes out and drips slowly into a collecting cup. On a modern plantation each tree is typically tapped every two or three days.

The peoples of Mesoamerica were working with rubber thousands of years before Europeans encountered it. In 1999 researchers at the Massachusetts Institute of Technology reported that by around 1600 BCE, people in the region were mixing latex from the Castilla elastica tree with juice from a species of morning glory vine. Untreated latex dries into a brittle material, but the mixture produced a substance elastic enough to make solid balls, which were used in a ritual ball game played on specially built courts. When Spanish invaders arrived in the sixteenth century, they were astonished by balls that bounced far higher than anything they had seen in Europe.

For a long time, however, Europeans regarded rubber as little more than a curiosity. In the mid-eighteenth century the French scientist Charles-Marie de La Condamine, who had travelled to South America with an expedition sent to measure the shape of the Earth, sent samples back to Paris and described how local people used the substance to make waterproof objects. The material acquired its English name in 1770, when the chemist Joseph Priestley noted that a small piece was excellent for rubbing out pencil marks. Its practical value was limited by a serious weakness: rubber became sticky and smelly in hot weather and hard and brittle in the cold.

Inventors in the early nineteenth century tried to overcome these problems. In 1823 the Scottish chemist Charles Macintosh patented a waterproof fabric made by placing a layer of rubber dissolved in naphtha between two layers of cloth, and raincoats are still sometimes named after him. The decisive breakthrough, however, came from the American inventor Charles Goodyear.

After years of unsuccessful experiments that left him deeply in debt, he discovered in 1839 that heating rubber with sulphur transformed it into a material that remained firm and elastic across a wide range of temperatures. The process became known as vulcanisation, after Vulcan, the Roman god of fire. Goodyear obtained an American patent in 1844. However, the English manufacturer Thomas Hancock, who had examined samples of Goodyear's rubber, had already secured a British patent for a similar process, and Goodyear gained little financial reward from his discovery.

Vulcanised rubber found countless uses, from machine belts and hoses to insulation for electrical wires, and demand rose sharply again after John Boyd Dunlop developed a practical pneumatic tyre for bicycles in 1888. Until the early twentieth century, almost all of this rubber came from wild trees in the Amazon, collected by tappers who often worked in harsh conditions and remained permanently in debt to the traders who supplied them. The trade brought enormous wealth to cities such as Manaus, deep in the Brazilian rainforest, where rubber barons built mansions and an opera house that opened in 1896.

The end of the Amazon's dominance began with a single shipment of seeds. In 1876 the British explorer Henry Wickham collected about 70,000 seeds of Hevea brasiliensis and transported them to the Royal Botanic Gardens at Kew, near London. Whether this should be described as smuggling has long been debated. Only a few thousand of the seeds germinated, and most of the resulting seedlings were sent to Ceylon, now Sri Lanka, with smaller numbers going to other British territories in Asia, including Singapore. There the botanist Henry Ridley, director of the Singapore Botanic Gardens, developed a way of tapping that removed thin slices of bark without seriously harming the tree, so that it could be tapped regularly for many years. Plantation rubber expanded rapidly, and by the 1910s it had overtaken wild rubber in world production.

Attempts to grow rubber on plantations in its native region largely failed, because South American leaf blight, a fungal disease, spreads rapidly among trees planted close together. In the late 1920s the car manufacturer Henry Ford established a vast plantation town in the Brazilian Amazon, known as Fordlandia, but disease and other difficulties meant that it never produced significant quantities of rubber. During the Second World War, Japanese forces occupied most of the Asian plantations, and the United States responded by building an industry that manufactured synthetic rubber from petroleum on a vast scale.

Natural rubber nevertheless remains indispensable. It resists tearing and heat build-up better than most synthetic alternatives, which is why it is still preferred for the tyres of heavy trucks and aircraft. Today most of the world's supply comes from smallholders in South-East Asia, with Thailand the largest producer. The leaf blight that defeated Fordlandia has never become established in Asia, but plant scientists regard it as a serious threat, since many Asian plantations are descended from a narrow genetic base and could prove highly vulnerable if it ever arrived.

For centuries, philosophers and astronomers speculated that other stars might have planets of their own, but until the 1990s there was no evidence that a single one existed. The difficulty was not a lack of interest but the sheer scale of the challenge. A planet shines only by reflecting the light of its star, which may be billions of times brighter, and from a distance of many light years the two appear almost to touch. Trying to see such a planet directly has often been compared to trying to spot a firefly beside a searchlight from thousands of kilometres away. Astronomers therefore had to find indirect ways of detecting planets through the effects they have on their stars.

The first confirmed discoveries came from an unexpected place. In 1992 the astronomers Aleksander Wolszczan and Dale Frail reported that tiny irregularities in the timing of radio pulses from a pulsar, the rapidly spinning remnant of a star that has exploded, could be explained by the gravitational pull of orbiting planets. These worlds, bathed in intense radiation, could hardly be less suitable for life, and many astronomers regarded them as oddities. Three years later, however, Michel Mayor and Didier Queloz of the University of Geneva announced the discovery of a planet orbiting 51 Pegasi, an ordinary star similar to the Sun. For this work they shared the Nobel Prize in Physics in 2019.

Mayor and Queloz used what is known as the radial velocity method. As a planet orbits, its gravity causes the star to move in a small circle, so that it alternately approaches and recedes from the Earth. These movements, sometimes amounting to only a few metres per second, shift the star's light very slightly towards the blue end of the spectrum and then towards the red. The planet they found, now called 51 Pegasi b, astonished astronomers. It has around half the mass of Jupiter yet completes an orbit in just over four days, which places it far closer to its star than Mercury is to the Sun. Existing theories held that giant planets could form only in the cold outer regions of a planetary system, so the discovery of these so-called 'hot Jupiters' forced theorists to accept that planets can migrate considerably after they form.

A second technique proved even more productive. If a planet's orbit happens to be aligned so that it passes in front of its star as seen from Earth, it blocks a small fraction of the starlight, causing a slight, regular dip in brightness. The size of the dip reveals the planet's diameter, and the interval between dips gives the length of its year. NASA's Kepler space telescope, launched in 2009, monitored about 150,000 stars in a single patch of sky almost continuously for four years and identified thousands of planets in this way. Its successor, TESS, launched in 2018, surveys nearly the entire sky, concentrating on bright stars relatively close to the Sun. By September 2025 the number of confirmed exoplanets had passed 6,000, and the great majority had been found by the transit method.

These surveys have transformed ideas about how common planets are. Statistical analyses of Kepler's results suggest that most stars in our galaxy have at least one planet, so planets probably outnumber stars. They have also revealed great variety. The most common type found so far is larger than the Earth but smaller than Neptune, a category that has no equivalent in our own solar system. Some of these may be rocky 'super-Earths'; others may be surrounded by thick envelopes of gas or by deep oceans. Astronomers have also found planets that orbit two suns, planets so hot that their surfaces are thought to be covered in molten rock, and giant planets whose average density is lower than that of polystyrene.

For many people, the most exciting question is whether any of these worlds might support life. Astronomers pay particular attention to the habitable zone, the range of distances from a star at which a planet with a suitable atmosphere could have liquid water on its surface. In 2016 a planet with roughly the mass of the Earth was found in the habitable zone of Proxima Centauri, the nearest star to the Sun, and the following year astronomers announced that TRAPPIST-1, a small, cool star about 40 light years away, has seven Earth-sized planets, several of which lie within its habitable zone. Being in the right place is no guarantee of suitable conditions, however. Small red stars like these frequently release violent flares that may strip away the atmospheres of nearby planets.

The next step is to study the atmospheres of exoplanets. When a planet passes in front of its star, a little of the starlight filters through its atmosphere, and the gases present absorb particular wavelengths. By analysing this light, astronomers can identify the molecules the atmosphere contains. In 2022 the James Webb Space Telescope provided the first clear detection of carbon dioxide in the atmosphere of an exoplanet, a hot gas giant known as WASP-39b. The ultimate aim is to detect biosignatures, combinations of gases that are difficult to explain without living organisms. The difficulty of this task was illustrated in 2025, when a claim that Webb had detected a possible sign of life on the planet K2-18b was quickly challenged by other researchers, who regarded the evidence as far from conclusive. Most astronomers believe that a convincing detection will require a new generation of telescopes designed specifically to study planets like the Earth.

In many classrooms, the pencil is losing ground to the keyboard. Children who once spent hours practising joined-up letters now learn to type on tablets, and university lecture halls glow with laptop screens. Some education systems have formally adjusted their priorities: in Finland, for instance, joined-up handwriting ceased to be a compulsory part of the curriculum from 2016, with pupils still learning to print letters but devoting more time to keyboard skills. Critics warn that something valuable is being lost; supporters reply that schools should prepare children for the world they will actually live in. The research evidence, as so often, is more complicated than either side tends to admit.

The most widely cited study in this debate was published in 2014 by the psychologists Pam Mueller and Daniel Oppenheimer. University students watched short recorded talks and took notes either by hand or on a laptop, and were then tested on what they had learned. Those using laptops wrote considerably more, but their notes contained a higher proportion of the speaker's exact words. On questions requiring conceptual understanding rather than recall of facts, the handwriting group performed better. The researchers' explanation was intuitively appealing: because writing by hand is slower, note-takers are forced to select and summarise, and this processing helps them understand. Typists, by contrast, can transcribe almost mechanically, and even explicit instructions not to copy word for word did not prevent them from doing so.

The study attracted enormous publicity. Later research, however, has been less conclusive. In 2021 a team led by Heather Urry at Tufts University repeated the original experiment with a larger group of students. They confirmed that laptop users write more and copy more verbatim, but found no difference between the two groups in conceptual understanding. When they combined their results with those of several similar studies, the overall advantage of handwriting was too small to be statistically reliable. This should make us wary of confident claims, particularly since students in these experiments were usually tested without any opportunity to review their notes.

The case for handwriting is considerably stronger when we turn to young children learning to read. In a 2005 study, the French researcher Marieke Longcamp and her colleagues taught preschool children to recognise letters either by writing them by hand or by typing them, and found that the older children in the handwriting group later recognised the letters more accurately.

Karin James of Indiana University used brain scanning to examine children who had not yet learned to read. After practising letters by printing them freehand, the children showed activity in brain regions associated with reading in adults when they looked at letters; children who had practised by typing or by tracing outlines did not. James has suggested that the variability of children's handwritten letters, which are rarely identical, helps them to learn what makes an 'a' an 'a'.

Studies of adults have pointed in a similar direction. In 2024 the Norwegian neuroscientists Audrey van der Meer and Ruud van der Weel recorded the brain activity of 36 university students while they either wrote words with a digital pen or typed them. Handwriting was associated with far more extensive communication between brain regions involved in memory, movement and sensory processing, and the researchers argued that this connectivity creates favourable conditions for learning. Other scientists have objected that a difference in brain activity is not the same as a difference in learning, and that the study did not directly measure learning at all. The objection is fair, and it illustrates a recurring problem in this field: findings from brain imaging are often reported as though they settled practical questions they were never designed to answer.

What, then, should schools do? In my view the evidence justifies continued teaching of handwriting in the early years, when children are learning the shapes of letters and the connection between letters and sounds. It does not, however, justify the special status that cursive script still enjoys in some debates. Most of the research favouring handwriting has compared writing by hand with typing, not joined-up writing with printing, and there is little evidence that one style of handwriting is superior to another for learning. Several American states have nevertheless passed laws in recent years requiring cursive to be taught, often on the grounds that children should be able to read historical documents. That may be a reasonable cultural goal, but it is a different argument from the cognitive one.

Nor should typing be treated as an enemy of learning. For pupils with motor difficulties such as dysgraphia, keyboards remove an obstacle that might otherwise prevent them from showing what they know. Typing also makes revision easy, and there is evidence that students often write longer and better-organised essays on a computer. Yet keyboard skills are not acquired automatically simply because children grow up surrounded by technology. Tapping on a touchscreen is quite different from touch-typing, and students who must search for each key gain few of the advantages that typing can offer.

The most sensible approach, then, is not to choose between pen and keyboard but to recognise what each does well. Young children benefit from forming letters by hand; older students need to type fluently; and adults taking notes would probably gain more from learning to summarise and review than from worrying about which tool they hold. The real danger lies not in technology itself but in decisions made on the basis of a single striking study, whichever side it appears to support.