IELTS Academic Reading Practice Test 1

Few everyday objects are as taken for granted as the pencil. It is cheap, it needs no power and, unlike most pens, it will write upside down or in freezing temperatures. Yet the familiar wooden pencil is the product of several centuries of experiment, accident and international rivalry, and its history reveals a surprising amount about how materials science developed long before the term existed.

The story begins in the sixteenth century in Borrowdale, a valley in the north-west of England, where local people discovered a deposit of an unusually pure, solid form of graphite. Shepherds reportedly used it to mark their sheep, but its value was soon recognised far beyond the valley. At the time, nobody understood what the substance was. Because it left a grey trail similar to that of lead, it was called 'plumbago', from the Latin word for lead, and this misunderstanding survives in the way people still talk about pencil 'lead', even though modern pencils contain no lead at all.

The Borrowdale deposit proved so valuable that it was eventually brought under tight official control. The mine was worked for only a short period each year and kept sealed for the rest of the time, and workers were searched as they left. Graphite was needed not only for writing but also for lining the moulds in which cannonballs were cast, which made it a material of military importance. Smuggling was nevertheless common, and in 1752 Parliament passed a law that made the theft of graphite a serious crime, punishable by hard labour or transportation to the colonies.

Early users simply wrapped a stick of raw graphite in string or sheepskin to keep their fingers clean. Later, craftsmen began to insert the sticks into hollowed-out pieces of wood. Exactly who first thought of encasing graphite in this way is unclear, and several countries have claimed the idea. The basic design of the modern pencil – two strips of wood glued together around a central core – became standard over the following centuries, although the method of production was gradually refined.

Outside England, pencil makers had to work with poorer material. In Germany, where the city of Nuremberg became a centre of the trade, manufacturers mixed powdered graphite with sulphur and other substances to bind it together. The results were serviceable but scratchy, and they never matched the smooth line produced by Borrowdale graphite. One business founded during this period, established by the cabinetmaker Kaspar Faber near Nuremberg in 1761, would later grow into one of the world's best-known pencil companies.

The decisive breakthrough came from France. During the wars of the 1790s, France could no longer import English graphite, and the government asked Nicolas-Jacques Conté, an engineer and inventor, to find an alternative. In 1795 Conté patented a process in which powdered graphite was mixed with clay and water, pressed into shape and then fired in a kiln. His method had two great advantages. First, it made good use of lower-quality graphite, which no longer needed to be found in solid blocks. Second, by changing the proportion of clay to graphite, manufacturers could control how hard or soft the core was. More clay produced a harder core and a fainter line; more graphite produced a softer core and a darker one.

This principle remains the basis of pencil grading today. In the system most widely used in Europe, 'H' indicates hardness and 'B' indicates blackness, with 'HB' in the middle of the range. Other countries developed their own systems; in the United States, for instance, pencils are often sold by number, with a 'number 2' roughly equivalent to an HB. Because there is no single international standard, however, two pencils with the same grade from different manufacturers may produce noticeably different marks.

In North America, pencil production expanded in the nineteenth century, and it attracted some unexpected figures. The writer Henry David Thoreau, best known for his book Walden, worked for several years in his family's pencil business in Massachusetts and helped to improve the quality of its products, partly by experimenting with finer grinding of the graphite. Meanwhile, in 1858, an American named Hymen Lipman received a patent for a pencil with an eraser attached to one end. The patent was later sold for a considerable sum, but in 1875 the US Supreme Court declared it invalid, ruling that simply combining two existing objects did not amount to a new invention.

Today, billions of pencils are produced every year, and most are still made using the core technique that Conté developed more than two centuries ago. Their continuing popularity is not simply a matter of habit. Pencil marks can be erased, they do not run when they get wet, and they make it easy to sketch an idea and then revise it, which is why artists, architects and carpenters continue to depend on them.

On a still summer evening, the centre of a large city can be several degrees warmer than the farmland that surrounds it. This phenomenon, known as the urban heat island, was first described in the early nineteenth century by Luke Howard, a London chemist and amateur meteorologist who is better remembered today for giving clouds the names that are still in use. Comparing his own temperature records with those taken outside the capital, Howard noticed that the city was consistently warmer, especially at night, and he attributed part of the difference to the heat produced by its many fires. Two centuries later, with more than half of the world's population living in urban areas, his observation has become a matter of real practical concern.

The causes of the effect are now well understood, and most of them are a consequence of the materials from which cities are built. Asphalt roads and dark roofs absorb a large proportion of the sunlight that falls on them rather than reflecting it back into the atmosphere; scientists describe such surfaces as having a low albedo. On a sunny afternoon, a dark roof or a car park can be far hotter to the touch than a nearby lawn, even when the air above both is at a similar temperature. Concrete, brick and stone also store heat during the day and release it slowly after sunset, which explains why the difference between city and countryside is often greatest at night. In addition, the tall buildings that line narrow streets form so-called 'urban canyons', which trap heat and reduce the cooling effect of the wind.

A second set of causes has to do with what cities lack. In the countryside, plants and moist soil cool their surroundings through a process called evapotranspiration, in which water drawn up by plants evaporates from their leaves, using energy that would otherwise warm the air. When fields and woodland are replaced by buildings and paved surfaces, rainwater is quickly channelled away into drains, and this natural form of air conditioning is largely lost. At the same time, cities generate a great deal of heat themselves. Vehicles, factories and, increasingly, the air-conditioning units used to keep buildings comfortable all release waste heat into the streets – so the more people try to cool their homes and offices, the warmer the outdoor air may become. Studies in several large cities have found that heat released by buildings and traffic is a significant source of warming in winter as well as in summer.

For much of the year, the consequences of a slightly warmer city may seem minor or even welcome; in colder climates, they can reduce the energy needed for heating in winter. During heatwaves, however, the effect can be dangerous. When nights remain hot, the human body has little opportunity to recover from the stress of the day, and elderly people, young children and those with existing health conditions are especially at risk. The European heatwave of 2003, which was associated with tens of thousands of deaths across the continent, prompted many governments to review how cities could be adapted to extreme temperatures. Higher temperatures also increase demand for electricity and can worsen air quality by speeding up the chemical reactions that produce ground-level ozone.

One of the simplest ways to reduce the effect is to change the colour of roofs. A 'cool roof', coated with white or highly reflective material, can stay considerably cooler in strong sunshine than a conventional dark one, lowering the temperature of the rooms below as well as that of the surrounding air. Some cities have introduced regulations or incentives encouraging their use, and similar principles are being applied to pavements and car parks. Critics point out, though, that reflective surfaces may increase glare at street level, and that in places with cold winters a white roof can slightly increase heating costs.

Vegetation offers a second approach. Street trees provide shade, which can make a striking difference to the temperature of pavements and walls, while parks and green roofs restore some of the cooling effect of evapotranspiration. Unlike reflective coatings, plants also bring other benefits, such as absorbing rainwater, supporting wildlife and improving the appearance of neighbourhoods. Yet trees take many years to reach maturity, they require water and regular maintenance, and in densely built districts there may simply be no space to plant them. Moreover, research suggests that the benefits of urban greenery are not always evenly shared: wealthier neighbourhoods frequently have more tree cover than poorer ones, so the residents who are most vulnerable to heat may receive the least protection.

Most researchers now argue that no single measure will be enough on its own. Instead, they recommend combining reflective materials, greenery and better urban design – for example, laying out streets to allow air to flow and providing shaded public spaces – with public health measures such as early-warning systems and cooling centres for vulnerable residents. As global temperatures continue to rise, the question for city authorities is no longer whether the urban heat island deserves attention, but how quickly they can act. Some have already begun to map temperatures street by street, using sensors or satellite images, so that cooling measures can be directed to the neighbourhoods that need them most.

Boredom has a poor reputation. It is associated with idleness, with restless teenagers and with the empty hours of long journeys, and few people would choose to experience it. Modern technology appears to offer a permanent cure: with a smartphone in almost every pocket, a moment of inactivity can be filled almost instantly. Yet over the past two decades, psychologists have begun to take boredom far more seriously, and some of their findings suggest that our eagerness to escape it may come at a cost.

Part of the difficulty in studying boredom has been deciding what it actually is. In 2012, a team led by the Canadian psychologist John Eastwood proposed a definition that has since been widely adopted: boredom, they argued, is the unpleasant experience of wanting to engage in satisfying activity but being unable to do so. This definition is useful because it distinguishes boredom from simple relaxation. A person lying contentedly on a beach is not bored, however little they are doing; what matters is the gap between the desire for engagement and the opportunity for it. Eastwood's group also linked boredom to problems of attention, suggesting that people become bored partly because they find it hard to focus on the task in front of them.

Earlier research had concentrated less on the experience itself than on the people who seemed most prone to it. In the 1980s, the American psychologists Richard Farmer and Norman Sundberg developed a questionnaire designed to measure how easily individuals become bored. Using this and similar tools, later studies found that people who score highly on 'boredom proneness' are more likely to report problems ranging from poor concentration to anxiety and impulsive behaviour. Such correlations do not prove that boredom causes these difficulties, but they help to explain why boredom was long treated as a symptom of something wrong.

Just how much people dislike having nothing to do was demonstrated dramatically in a series of experiments published in 2014 by Timothy Wilson and his colleagues at the University of Virginia. Participants were asked to sit alone in a bare room for between six and fifteen minutes, with no phone, book or other distraction, and simply to entertain themselves with their own thoughts. Most reported finding the experience unpleasant. In one version of the study, participants were given the option of pressing a button to give themselves a mild electric shock – a sensation that, earlier in the session, many had said they would pay money to avoid. Remarkably, a substantial number chose to shock themselves rather than sit quietly, and men were considerably more likely to do so than women.

If boredom is so unpleasant, why should it be valued? One answer comes from research on creativity. In a widely reported study, the British psychologists Sandi Mann and Rebekah Cadman asked one group of participants to spend fifteen minutes copying numbers out of a telephone directory, a deliberately tedious task, before completing a test of creative thinking in which they had to suggest as many uses as possible for a pair of plastic cups. Those who had first done the boring task produced more ideas than a control group who went straight to the creative test. Mann and Cadman suggested that boredom encourages the mind to wander, and that daydreaming may help people make unusual connections.

A different explanation, put forward by the American social psychologist Erin Westgate, treats boredom as a kind of signal. According to her model, people feel bored when an activity is either not meaningful to them or fails to hold their attention – because it is too easy, too difficult, or simply not engaging. On this view, boredom is no more a flaw than hunger or pain; it is a message telling us that what we are doing is not working and that we should change course. A student who is bored in a lecture might need more challenging material, or might simply need to understand why the material matters.

If this is correct, the habit of reaching for a phone at the first hint of boredom may be counterproductive. Digital distraction removes the unpleasant feeling, but it also removes the signal, leaving the underlying problem unaddressed. It may also deprive us of the kind of undirected thinking that Mann and Cadman associated with creative ideas. It is even possible that constant stimulation makes ordinary activities seem duller by comparison, so that the more we avoid boredom, the more easily we become bored.

None of this means that boredom should be welcomed uncritically. Chronic boredom, particularly in workplaces or schools where people have little control over what they do, is associated with disengagement and poor wellbeing, and simply telling someone to 'embrace' it would be of little help. Nor is it obvious that the creative benefits found in laboratory studies would appear in everyday life, where people are rarely asked to invent new uses for plastic cups. Nevertheless, the evidence seems strong enough to justify a modest change of habit. Rather than treating every idle moment as a problem to be solved, we might occasionally allow ourselves to be bored – and pay attention to what that feeling is telling us.