IELTS Academic Reading Practice Test 488

In the 1840s the search for a sea route linking the Atlantic and Pacific across the top of North America had occupied British navigators for three centuries. Much of the eastern half of such a route had been charted, but a long stretch of water remained unmapped, and the Royal Navy was determined to claim it. In 1845 the Admiralty appointed Sir John Franklin, an officer with Arctic experience, to lead an expedition through the remaining gap. Two ships, HMS Erebus and HMS Terror, left Kent in May 1845 with 129 men on board. In late July, whaling vessels in Baffin Bay saw the ships moored to an iceberg, waiting for the ice to break up. No European would see the crews again.

Much was expected of the vessels. Both had been built to bombard coastal fortifications and were therefore unusually strong, their hulls thick enough to withstand the recoil of heavy mortars. For the Arctic they were given iron plating along the bows, steam engines adapted from railway locomotives, and screw propellers that could be lifted clear of the water when the ships were under sail. They carried coal for the engines, equipment for distilling drinking water from the sea, and a library of more than a thousand volumes. Above all they carried food: barrels of salted meat and vegetables and thousands of tins of preserved meat and soup, sealed by a process that was still new.

The first winter was spent at Beechey Island, off the south-west coast of Devon Island. Three members of the crew died there and were buried in the frozen ground. When their bodies were exhumed by researchers in the 1980s they were found to be remarkably well preserved, and examination of their tissues and hair provided some of the first scientific evidence about the expedition's decline.

Early in September 1846 the ships were trapped by ice off King William Island and could not be freed. According to the only written record to survive, Franklin died on 11 June 1847. The document, a printed form filled in and left inside a stone cairn at Victory Point, was found in 1859 by a search party led by Francis Leopold McClintock; a note added to its margins in April 1848 reported that the survivors had abandoned their ships.

That second message was stark. It gave the date, 25 April 1848, recorded that nine officers and fifteen men had died, and stated that the remaining 105 men had left the ships and were marching south towards the Back River on the mainland. It said nothing about their supplies or their condition. Those who later examined the few relics scattered along the route concluded that the party had been exhausted, and that some of the men had died within a short distance of the ships.

The search for the missing men began almost immediately and continued for decades. Franklin's wife, Jane, campaigned relentlessly for further expeditions and paid for several of them herself. Much of what is known about the crews' final months came instead from Inuit testimony. In 1854 the explorer John Rae reported that Inuit people had told him of the party's suffering and had described evidence of cannibalism. The claim outraged many Victorians; Charles Dickens published a fierce attack on Rae's account. Examinations of bones in the twentieth century, many of them marked by cuts, showed that the Inuit accounts had been accurate.

Why the men died has been argued over for more than a century. The early assumption was simple starvation, but the bodies at Beechey Island showed signs of tuberculosis, and conditions on the ships were unsanitary. In the 1980s Owen Beattie, an anthropologist at a Canadian university, proposed that lead poisoning had played a central part: the solder used to seal the tins, he argued, had contaminated the food, and the ships' water systems were also lead-rich. Lead was certainly present in the men he studied. Whether the quantities were enough to kill them, rather than merely worsening a general decline, is still disputed, and more recent analyses have pointed to scurvy, tuberculosis and a deficiency of zinc.

The ships themselves remained undiscovered for a century and a half. A renewed search, guided in part by the knowledge of Inuit historians, located Erebus in 2014 in Wilmot and Crampton Bay and Terror in 2016 in Terror Bay, both close to King William Island. Divers have recovered objects including a ship's bell and plates stamped with a naval crest, and have found that much of the interior is intact in the cold, dark water. Both wrecks are protected as national historic sites. Another vessel, HMS Investigator, which had sailed in search of Franklin in 1850, was found in 2010 in Mercy Bay.

Historians have drawn wider lessons from the disaster. The expedition was planned by men confident that superior equipment could overcome the Arctic, and distrustful of the knowledge of the Inuit who lived there. The lesson most often drawn today is that technology without local understanding can be dangerous. The route the crews were seeking, meanwhile, is opening: the Northwest Passage is now partly navigable in some summers, and ships have sailed it. The ice that held Erebus and Terror is no longer the barrier it once was.

A sinkhole is a depression in the ground that forms when material below the surface is removed and the ground above can no longer be supported. Some appear gradually, as a shallow hollow that deepens over many years; others open without warning, swallowing roads, cars and occasionally houses. Their size ranges from a few metres across to several hundred. They occur on every continent and in almost every kind of landscape, but they are far more common where the rock beneath the soil can be dissolved by water.

Such rock is described as soluble, and the landscapes formed on it are known as karst. Limestone, dolomite, gypsum and rock salt are all soluble to some degree. Rainwater is naturally slightly acidic, because it picks up carbon dioxide on the way down and again in the soil, forming a weak carbonic acid. This acid attacks calcium carbonate, the mineral of which limestone is largely composed, and carries it away in solution. The process is extremely slow by human standards: a layer of limestone may lose only a fraction of a millimetre in a century. Over hundreds of thousands of years, however, the results are dramatic.

Water does not dissolve rock evenly. It concentrates along joints, bedding planes and faults, cutting narrow channels that widen over time into shafts and caves. A landscape may come to resemble a sieve, with streams vanishing into the ground and reappearing kilometres away, and most of the world's cave systems form in this way. As the openings grow, the rock above them becomes thinner. Where the soluble rock lies close to the surface, the roof of a cave may eventually become too thin to support the soil above it.

Geologists distinguish several kinds of sinkhole. A dissolution sinkhole forms where the surface itself is eaten away, producing a broad, shallow bowl. A cover-collapse sinkhole is the dramatic kind shown in news reports: a cavity develops in the soluble rock beneath a layer of soil, the soil is washed down into it, and a void grows upward until the surface gives way. Cover-subsidence sinkholes occur where the soil is sandy and trickles gradually into the opening, so that the ground sags rather than collapses. Clay-rich soils are the most dangerous, because they can bridge a cavity for years before failing suddenly.

Human activity greatly increases the risk. Pumping water from wells lowers the water table, removing the buoyancy that helps to hold up the material above a cavity. Leaking drains, burst pipes and over-watered gardens do the opposite, washing loose soil into cracks. Heavy rain after a long dry spell is a classic trigger, since the ground is already weakened and the weight of saturated soil may be enough to finish the job. Construction work, quarrying and the extraction of salt or potash can also create cavities directly, sometimes at considerable depth. In some regions the removal of groundwater for irrigation has been followed by clusters of collapses within a few years.

The shores of the Dead Sea offer an unusually clear illustration. Because the sea has been shrinking, as water is diverted from its feeder rivers and minerals are extracted, fresh groundwater has flowed into the exposed coastal deposits. That water dissolves underground layers of salt, and since the 1990s thousands of sinkholes have opened along the shore, forcing roads and farmland to be abandoned. Nothing about the chemistry is unusual; what is unusual is the speed at which a natural process has been accelerated by human use of water, and the cost of that acceleration to the people who live nearby.

Detection is difficult but not impossible. Satellite measurements can reveal the slight sinking of the ground that often precedes a collapse, and ground-penetrating radar and electrical surveys can map cavities at shallow depth, though neither method works everywhere. Drilling gives certainty, but only at the points where holes are made, and a site may contain dozens of cavities.

Property owners are advised to watch for warning signs: circular depressions, cracks in walls and pavements, doors and windows that no longer close, fences and poles that lean, and muddy water appearing in a well or pond. Records kept by geological surveys, together with reports from the public, allow local authorities to build up maps of areas where cavities are likely.

What remains genuinely uncertain is timing. Engineers can often say that a cavity exists, but not whether it will collapse this year, in fifty years or never, because the strength of the material above it depends on moisture, on the weight of buildings and on details of the rock that are rarely visible from the surface. Filling a hole with concrete or rubble may solve the immediate problem without addressing its cause, and a further collapse may follow nearby.

Insurance claims and planning decisions have made sinkholes a matter of public policy as well as geology. In several countries, maps of known cavities must now be consulted before large buildings are approved, and some regions require homeowners to disclose sinkhole damage when they sell a property. Meanwhile the areas at risk are not shrinking. Much of the Mediterranean, southern China, Florida and the limestone belt of central England rests on soluble rock, and in many cities the combination of ageing pipes, rising demand for water and heavier rainfall is increasing the strain on ground that was never stable to begin with.

Selective universities have long asked applicants to describe what they do outside the classroom, and in the United States the practice is embedded in a system of 'holistic' review in which grades, test scores, essays and activities are weighed together. The justification is straightforward. Examination results measure a narrow range of abilities, and an institution that admits on that basis alone may exclude students who would contribute a great deal to seminars, laboratories and student societies. A form that lists a sport, a part-time job or a role in a school production is an attempt to see the applicant as something more than a set of marks.

Defenders of the practice make a second argument, about character. Sustained involvement in a team, an orchestra or a community project, they maintain, demonstrates persistence, cooperation and the capacity to organise other people, and these qualities matter at university and afterwards. Admissions officers at highly selective institutions often say that a group made up entirely of applicants with perfect grades would be dull, and would learn less from one another. On this view the activity list is not a decoration but evidence about how a student is likely to behave when the work becomes difficult and nobody is checking.

Critics reply that such evidence is not equally available to everyone. Taking part in organised activities costs money and time: subscriptions, instruments, equipment, travel, and the unpaid internships that are said to look impressive on an application. A student who spends four evenings a week stacking shelves to help the family budget is showing considerable determination, but the form offers no obvious box in which to record it. Surveys of teenagers in several countries consistently find that those from better-off households are more likely to take part in structured activities outside school.

A second objection is that any measure which applicants know is being used will be manipulated. In countries where the stakes are high, a commercial industry has grown up around the process, offering coaching, editing and advice on which activities to choose. Schools in affluent areas run programmes designed to produce exactly the kind of record that admissions offices admire, and a few families establish charities or clubs for no other purpose. Once a signal becomes a target it loses much of its value: when thousands of applicants present similar lists, the lists stop distinguishing between them.

The third question concerns evidence. Do extracurricular activities actually predict anything? The answer appears to be that they predict a little, and largely because they are correlated with the advantages that already predict success. Careful analyses that allow for prior attainment and family background tend to find that the additional predictive power is modest. This does not make the activities worthless; it makes them unreliable as a sorting device, particularly when they are rated by readers who must assess very different opportunities in very little time and with no common standard.

One response is not to abandon the information but to read it more carefully. Contextual admissions, as the approach is known, compares what an applicant has achieved with what was available to them. A student who set up a debating society at a school that had none has done something different from a student who joined an established one, and a system that cannot tell the difference is measuring circumstances rather than effort. Several universities now ask applicants how many hours they work in paid employment, and a few give that question real weight.

The machinery of application is also being redesigned. In Britain, the admissions service has replaced the single free-text personal statement with a series of structured questions, one aim being to reduce the advantage of applicants who can buy help with drafting. Requiring everyone to answer the same questions in the same order does not eliminate advantage, but it makes comparison less dependent on fluency and confident self-presentation, and it obliges applicants to provide specific examples rather than general claims about their enthusiasm.

My own view is that extracurricular activities should stay in the file, but should be weighted less heavily and read more carefully. The mistake is to treat them as certificates of virtue, interchangeable units that can be counted and ranked. What matters is what an applicant did with the opportunities actually open to them, and that is a question about context, not about quantity. Universities should therefore require evidence of what an activity involved, give serious credit to paid work and caring responsibilities, and publish data showing whether the applicants they admit from different backgrounds actually enrol and succeed. Dropping the practice would be simpler, but it would also remove information that, used honestly, can widen access rather than narrow it.