IELTS Academic Reading Practice Test 37

When the Venetian merchant Marco Polo returned from China at the end of the thirteenth century, he described a remarkable ceramic that few Europeans had ever seen. The word later used for it, porcelain, comes from the Italian porcellana, a name for the cowrie shell, whose smooth and glossy surface the material resembled. For the next four hundred years, Europeans prized Chinese porcelain so highly that it was sometimes called 'white gold', and kings and nobles competed to fill entire rooms with it. Yet despite repeated attempts, no European workshop could discover exactly how it was made.

Porcelain differs from other ceramics because of both its ingredients and the heat at which it is fired. Earthenware, the oldest type of pottery, is fired at relatively low temperatures and remains porous, so it must be glazed if it is to hold liquids. Stoneware is fired more strongly and is harder and waterproof, but it is usually grey or brown and completely opaque.

Chinese porcelain, by contrast, was made from two main materials: kaolin, a fine white clay named after a hill near the town of Jingdezhen, and porcelain stone, a rock that was crushed and formed into small bricks known as petuntse. When this mixture is fired at around 1,300 degrees Celsius, the stone melts into a kind of glass that binds the particles of clay together. The result is a body that is white, hard and non-porous. Where it is thin enough, it is also translucent, and it rings clearly when it is tapped.

Historians disagree about exactly when true porcelain first appeared, partly because they define it in different ways, and the dates they propose range across several centuries. What is clear is that by the Song dynasty (960–1279) Chinese potters were producing refined white and pale-blue wares, and that Jingdezhen, in Jiangxi province, was becoming the country's most important centre of production. The town had abundant supplies of both raw materials, extensive forests to provide fuel, and rivers to carry finished goods away. Over time it grew into what was effectively an industrial city, in which the work was divided among specialists who prepared the clay, shaped the vessels, painted them or tended the kilns.

Much of the pottery made in southern China was fired in what is known as a dragon kiln. This was a long, narrow tunnel with an arched roof of bricks, built up a hillside at an angle that typically lay between about ten and twenty degrees. Firing began in a firebox at the lower end. Because hot air rises, the flames and gases were drawn up the slope towards a chimney at the top, heating the kiln far more efficiently than a flat structure could.

Once the lowest section had reached the necessary temperature, workers fed wood through a series of stoke holes in the side walls, moving gradually up the kiln so that each section was brought to full heat in turn. To protect the pots from flames and falling ash, they were placed inside clay boxes called saggars, which could be stacked on top of one another. Some dragon kilns were several tens of metres long, and a single firing could produce many thousands of pieces.

The most famous Chinese export ware, blue-and-white porcelain, developed during the Yuan dynasty in the fourteenth century. Its decoration was painted onto the unfired vessel with cobalt, much of it imported from Persia, and then covered with a clear glaze, so that the design was sealed beneath a glassy surface. At first much of this ware was made for markets in the Islamic world, but from the sixteenth century Portuguese and later Dutch traders shipped vast quantities to Europe. The demand encouraged European potters to produce imitations, such as the tin-glazed earthenware of Delft in the Netherlands, which copied Chinese designs but lacked the hardness and translucency of the original.

The European breakthrough came in Saxony, in what is now Germany. Its ruler, Augustus the Strong, was an obsessive collector of Asian porcelain, and he supported the experiments of Ehrenfried Walther von Tschirnhaus, a mathematician and scientist, together with Johann Friedrich Böttger, a young alchemist whom Augustus was keeping under guard in the hope that he would produce gold. The two men first succeeded in making a hard red stoneware, and after Tschirnhaus died in 1708, Böttger developed a white porcelain using kaolin from Saxony. Historians still debate how much of the credit belongs to each of them. In 1710 Augustus founded a royal porcelain manufactory in the castle at Meissen. Its methods were guarded as a state secret, but workers who left Meissen took their knowledge with them, and within a decade a rival factory had been established in Vienna.

Meanwhile, a French Jesuit missionary, François Xavier d'Entrecolles, was working in the region around Jingdezhen. In letters sent to Europe in 1712 and 1722, he described in detail how the city's potters prepared their materials and fired their wares, providing the first extensive account of Chinese methods in a Western language. In England, potters took a different route. Towards the end of the eighteenth century they perfected bone china, in which a large proportion of ash made from animal bones was added to the clay. The result was strong, white and translucent, and it became Britain's characteristic contribution to the history of fine ceramics. In English, however, the material is still commonly called simply 'china', a reminder of where it was first made.

In the 1950s an engineer named Frank Watlington was working for the United States Navy in Bermuda, where hydrophones – underwater microphones – had been installed to listen for the sounds of Soviet submarines. Among the noises they picked up were long sequences of moans, groans and high-pitched cries, which he eventually identified as coming from humpback whales passing the island. In 1967 he passed his recordings to two young American biologists, Roger and Katy Payne, who had travelled to Bermuda hoping to learn more about the animals.

Working with the scientist Scott McVay, Roger Payne converted the recordings into spectrograms, visual representations that show how the pitch and loudness of a sound change over time. The images revealed something unexpected: the whales' sounds were not random but were arranged in a precise hierarchy. Individual sounds, or units, were combined into phrases; a phrase was repeated several times to form a theme; and a series of themes, always delivered in the same order, made up a song. A complete song might last from about ten to twenty minutes, and a whale could repeat it, almost without a break, for many hours. Payne and McVay described their findings in the journal Science in 1971, arguing that the term 'song' was justified by this patterned repetition. A year earlier, an album of the recordings had been released to the public. It became one of the best-selling natural history records ever produced and gave momentum to the international campaign to end commercial whaling.

Later research established that, among humpbacks, it is only males that sing. Singing is most intense in the warm tropical waters where the animals breed during the winter months, although songs are also heard along migration routes and occasionally in colder feeding areas. Most striking of all, at any one time the males in a population all sing essentially the same song. Yet the song does not stay fixed. Over a breeding season and from one year to the next, it gradually changes, as units are altered, phrases shortened or themes dropped, and every singer adopts the modifications. Because the changes are learned from other whales rather than inherited, many researchers regard humpback song as one of the clearest examples of culture in a non-human animal.

An even more dramatic form of change was documented by a team led by Michael Noad off the east coast of Australia. Between 1995 and 1998, the researchers used hydrophones suspended from buoys and small boats to record humpbacks migrating past Queensland. In 1996 they detected a few males singing a song that was entirely different from the local one but closely matched the song of the population that migrated along Australia's west coast, in the Indian Ocean. Within two years, the new song had completely replaced the old one. In their 2000 paper in Nature, the authors described this as a cultural revolution, apparently triggered by a small number of foreign singers, and they suggested that novelty itself might be attractive to the whales.

Later work showed that such revolutions are not isolated events. Analysing 775 songs recorded across the South Pacific over a number of years, Ellen Garland and her colleagues reported in 2011 that new songs regularly spread from population to population, usually originating off eastern Australia and moving eastwards, as far as French Polynesia, over about two years. In 2025, a study in Science by an international team including Garland applied methods borrowed from research on how infants learn to divide a continuous stream of speech into words. Using eight years of recordings from New Caledonia, the team found that the frequencies of the song's sound sequences followed Zipf's law, a statistical pattern in which a few elements are very common and most are rare. The same pattern is found in human languages, but the authors stressed that whale song does not carry meaning in the way that language does. Instead, they suggested, similar structures may make any culturally transmitted system easier to learn.

How whales produce these sounds was long unclear, because researchers cannot observe the vocal organs of a singing whale directly. In 2024 a study published in Nature, led by the biologist Coen Elemans, examined larynxes removed from three baleen whales – a humpback, a sei whale and a minke whale – that had died after stranding. When air was blown through them, a U-shaped structure pressed against a fatty cushion, which vibrated to produce low-frequency sound. However, computer models built by the same team suggested that this arrangement also restricts whales to a limited range of low frequencies and to relatively shallow depths, and that this range overlaps with the noise produced by ships.

Humpbacks are not the only singers. Blue whales and fin whales produce simpler but extremely low-pitched songs that can travel great distances through the ocean. In 2009 researchers reported that the pitch of blue whale songs had been falling worldwide; off California, it dropped by roughly 30 per cent between the 1960s and the early 2000s. The reason remains uncertain, although the authors' preferred explanation was linked to the recovery of whale numbers after commercial whaling ended. The purpose of song itself is also still debated: it may attract females, help males compete with one another, or both. As ocean traffic grows, scientists are concerned that rising levels of underwater noise may make it harder for whales to hear one another at all.

Few customs provoke as much quiet anxiety as tipping. In the United States, where leaving 15 to 20 per cent of a restaurant bill has long been expected, the practice has recently spread far beyond the dining table. Touchscreen payment terminals now invite customers to add a tip when they buy a coffee, collect a takeaway order or even use a self-service kiosk, and many people say they feel pressured into paying more than they intended. I want to suggest that the evidence points the other way: tipping is a poor way of motivating staff, an unreliable and sometimes unfair way of paying them, and a habit that would be better replaced than reformed.

It is worth remembering that tipping has not always been accepted, even in America. The custom is generally thought to have arrived from Europe in the decades after the Civil War, when wealthy Americans who had travelled abroad began to imitate the habits of the European upper classes. It quickly became associated with occupations in which employers paid little and left workers to depend on customers' generosity – most notoriously at the Pullman Company, which employed formerly enslaved Black men as porters on its sleeping cars. Many contemporaries found the practice offensive. In 1916 William Rufus Scott published The Itching Palm, a book attacking tipping as a form of servility incompatible with a democratic society, and between 1909 and 1915 six states, among them Washington and Iowa, passed laws prohibiting it. These laws proved almost impossible to enforce, however, and all of them had disappeared by the mid-1920s.

The strongest argument in favour of tipping is economic. If customers pay servers directly according to how well they are treated, the reasoning goes, servers have a powerful incentive to work hard, and managers are spared the difficult task of monitoring every table. This is an attractive theory, and it is not absurd. But it depends on a simple empirical assumption: that the size of a tip actually reflects the quality of the service received.

Decades of research suggest that it does not, or does so only very weakly. Michael Lynn, a specialist in consumer behaviour at Cornell University who has studied tipping since the 1980s, has combined the results of many separate studies and found that service quality accounts for only a tiny fraction of the variation in tips – in one analysis, less than two per cent. The size of the bill, by contrast, is consistently the best predictor of how much a customer leaves. People seem to tip largely out of habit and a sense of social obligation, adjusting the amount only slightly according to how they were treated.

What does influence tips is often unrelated to the work itself. In a study published in 1990, servers who introduced themselves by name received larger tips than those who did not. Another experiment, at a restaurant in Philadelphia, found that a waitress who drew a smiling face on customers' bills increased her tips, whereas a waiter who did the same saw his tips fall. Other researchers have found that a brief touch on the customer's hand or shoulder, or crouching beside the table to take an order, makes customers more generous. None of these gestures makes food arrive faster or a table cleaner. More troubling, studies have found that tips can vary with a server's appearance, gender and ethnicity, so the system may reward characteristics that have nothing to do with effort and that employers would be forbidden to consider when setting wages.

These distortions matter because, for many workers, tips are not a bonus but the bulk of their income. Under United States federal law, employers may pay tipped staff a cash wage of just $2.13 an hour – a figure that has not changed since 1991 – provided that tips bring their total earnings up to the general minimum wage of $7.25. Earnings therefore rise and fall with the weather, the day of the week and the mood of individual customers. Tipping also creates divisions within the workplace. In many restaurants, cooks and dishwashers, who often receive no share of the tips, may earn less than the waiting staff they work alongside, even though their contribution to the customer's experience is just as great.

Some business owners have tried to break the habit. In 2015 the New York restaurateur Danny Meyer announced that his restaurants would abolish tipping and raise menu prices instead, partly in order to narrow the pay gap between the dining room and the kitchen. The experiment lasted around five years before tipping was reintroduced in 2020, during the COVID-19 pandemic. Because diners compare menu prices between restaurants, a business that includes the cost of service in its prices appears more expensive than its competitors, even when the final bill is similar. Some experienced servers, meanwhile, preferred to work in places where generous customers could raise their income.

The lesson, in my view, is not that tipping is inevitable but that it cannot be abolished by individual businesses acting alone. Countries such as Japan, where tipping is not customary, show that attentive service does not depend on it. Change is more likely to come through legislation requiring all employers to pay at least the full minimum wage before tips, as seven American states, including California, already do. Until such reforms become widespread, however, refusing to tip would punish the very workers who depend on the system rather than the system itself. The fairest course for customers is to keep tipping while supporting the case for change.