Reading the Sky: The Science of Lightning
For most of recorded history, lightning was read as a message rather than measured as a force. Cultures across the world attributed the bright, jagged flashes to the tempers of their gods, and temples were sometimes built where bolts had struck, on the assumption that such places were marked out as sacred. The first serious challenge to this view came in the eighteenth century, when the American Benjamin Franklin proposed that lightning was simply a large-scale form of the electrical spark that could be produced in a laboratory. His famous, and extremely dangerous, experiment with a kite flown into a storm cloud is often credited with proving the point, though historians still argue over exactly what he did and when.
Modern accounts begin not with the flash but with the cloud that produces it. A thundercloud is a churning column of rising and falling air in which water exists as droplets, as ice crystals and as soft hail known as graupel. As these particles are hurled up and down and collide, they exchange electric charge: lighter ice crystals, carried to the top of the cloud, tend to become positively charged, while heavier graupel, sinking towards the base, carries negative charge downwards. Over time this sorting produces an enormous difference in charge between the upper and lower regions of the cloud, and between the cloud base and the ground below. Air is normally an excellent insulator, but once the difference becomes great enough, that resistance is overwhelmed.
The discharge that follows is far more intricate than the eye can register. It usually begins with a faint, branching channel called a stepped leader, which pushes down from the cloud in a series of rapid jumps, each advancing the channel a few tens of metres. When this descending channel nears the ground, an upward streamer rises to meet it, often from a tall or pointed object. The instant the two connect, a colossal current surges back up the established channel — the return stroke — heating the surrounding air to roughly five times the temperature of the Sun's surface. It is this sudden, violent expansion of superheated air that we hear, moments later, as thunder. The whole sequence is over in less than a tenth of a second.
An event so brief and so unpredictable is remarkably hard to study directly, and researchers have gone to unusual lengths to pin it down. One technique is to fire a small rocket trailing a thin wire into a passing storm, deliberately triggering a strike that then follows the wire to a waiting bank of instruments — in effect, ordering lightning to appear on cue. High-speed cameras, capable of thousands of frames a second, have revealed the stepped leader's stuttering descent, while networks of ground sensors pinpoint each flash by timing the radio pulses it emits at slightly different stations. These same detection networks, originally built for research, now feed directly into the systems that meteorologists use to track the movement and strengthening of storms.
The study of lightning has turned up benefits that its early observers could hardly have guessed at. The intense heat of a strike splits nitrogen molecules in the air, allowing them to combine with oxygen and eventually reach the soil in a form that plants can absorb — a natural fertiliser produced on a scale that, though modest beside industrial output, has shaped ecosystems for millions of years. More practically, the rate at which a storm produces lightning turns out to be a reliable guide to how dangerous it is becoming: a sudden surge in flashes often precedes heavy rain, hail or a tornado, giving forecasters a valuable early warning that other measurements may miss.
None of this has made lightning safe to ignore. It still kills thousands of people a year, most of them in poorer regions where outdoor work and flimsy shelter offer little protection, and some researchers warn that a warming climate may increase the frequency of strikes in certain areas. What has changed is the character of our ignorance. Where our ancestors saw an unanswerable sign from above, we now see a process we can partly predict, partly harness and increasingly measure — even if the finer details of how a cloud decides, in a given instant, to unleash its charge remain surprisingly unsettled.
Reading Passage 1 has six paragraphs, A–F. Choose the correct heading for each paragraph from the list of headings below. Write the correct number, i–ix, next to each paragraph.
- i From a divine sign to an electrical spark
- ii How a cloud builds up its charge
- iii The split-second anatomy of a strike
- iv Methods for capturing a fleeting event
- v Surprising benefits and useful warnings
- vi Persistent dangers and remaining puzzles
- vii The place of lightning in ancient religion
- viii Recreating lightning inside the laboratory
- ix Measuring the exact height of thunderclouds
Do the following statements agree with the information given in Reading Passage 1? Write TRUE if the statement agrees with the information, FALSE if it contradicts it, or NOT GIVEN if there is no information on this.
Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer.
Whose Treasure? Museums and the Fight over Return
Walk through the great museums of London, Paris or Berlin and you will pass objects gathered from every corner of the globe: bronze plaques from West Africa, marble sculptures from ancient Greece, manuscripts and masks and mummies removed from their places of origin, often more than a century ago. For most of that time, their presence went largely unquestioned by the institutions that held them. In recent decades, however, a growing number of governments, communities and campaigners have demanded that such items be sent home. The dispute over cultural repatriation — the return of objects to the places or peoples from which they came — has become one of the most heated arguments in the museum world, and it shows no sign of being settled.
Those who argue for return rest their case above all on the circumstances of acquisition. A large proportion of the contested objects left their homelands during periods of colonial rule or military conquest, when the people who made them had little say in the matter. To keep such items, campaigners contend, is to profit from an injustice and to prolong it: a mask or a carving is not merely an artwork but a piece of a community's history and identity, and its absence can be felt as a continuing wound long after the generation that lost it has passed. From this perspective the question is essentially a moral one, and it is straightforward. If an object was taken unfairly, the honourable course is to give it back, and arguments about who can best display or care for it are beside the point.
The institutions that hold these collections have often replied with what is sometimes called the 'universal museum' argument. Great collections, on this view, allow visitors to see the achievements of many civilisations side by side, under one roof, and so to appreciate the shared inheritance of humanity in a way that scattered, local displays cannot. A sculpture removed from its original setting, the argument continues, gains a new value as part of a global conversation, and the millions who pass through a major museum each year would be unable to travel to see it in its country of origin. Defenders also point to their expertise in conservation, insisting that objects are safer and better studied where they now are.
In practice, the picture is rarely so clear-cut on either side. Establishing where an object truly came from, and how it changed hands, can be extraordinarily difficult; records are patchy, and an item may have passed through many owners before reaching a museum. National laws differ sharply, and some museums are legally forbidden from disposing of items in their collections, whatever their directors might wish. There is also the delicate question of who, today, has the strongest claim: a modern government, a religious community, the descendants of the original makers, or some combination of these, whose interests may not coincide. Good intentions can founder on the sheer complexity of the facts.
Faced with these difficulties, some institutions have looked for solutions that stop short of outright return. Long-term loans allow an object to travel back to its homeland for years at a time while ownership remains, at least formally, unchanged. Others have entered into agreements of shared stewardship, in which two institutions jointly decide how an object is cared for and displayed. Advances in technology have added a further option: highly accurate replicas and detailed digital scans, which allow an object to be studied and admired in more than one place at once. To their supporters, such arrangements offer a pragmatic middle way; to their critics, they can look like a means of avoiding the central question.
A few commentators go further, warning that the focus on returning objects may itself be misplaced. Handing back a famous artefact, they suggest, can become a symbolic gesture that costs a wealthy institution little while leaving the deeper inequalities between nations untouched. Others raise the familiar fear that a single high-profile return would open the floodgates, emptying the world's great museums; supporters of repatriation tend to dismiss this as scaremongering, noting that most requests concern a small number of specific, deeply significant items rather than entire collections. The disagreement is not only about principle but about consequences, and about which consequences are being honestly weighed.
What seems beyond dispute is that the debate has already changed the museums at its centre. Many have begun to research the origins of their holdings more openly, to acknowledge how particular objects were obtained, and to display that history alongside the objects themselves rather than hiding it. Whether or not a given item is ultimately returned, the assumption that a museum may simply keep whatever it has gathered, and need not explain how, no longer holds. In that sense the argument has been productive even where it remains unresolved.
Choose the correct letter, A, B, C or D.
Look at the following statements and the list of groups below. Match each statement with the correct group, A–D.
- A Supporters of repatriation
- B Defenders of the universal museum
- C Advocates of middle-way arrangements
- D Sceptics about the value of return
Complete the summary below. Choose NO MORE THAN TWO WORDS from the passage for each answer.
Do the following statements agree with the claims of the writer in Reading Passage 2? Write YES if the statement agrees with the claims of the writer, NO if it contradicts them, or NOT GIVEN if it is impossible to say what the writer thinks.
Counting Contentment: The Economics of Wellbeing
For most of the past century, the success of a nation has been judged largely by a single number: its gross domestic product, or GDP, the total value of the goods and services it produces. The measure has obvious attractions. It is comparable across countries, it can be tracked from one quarter to the next, and it rises, on the whole, when more people are in work and factories are busy. Yet its inventors warned from the outset that it was never meant to capture the welfare of a population, only its output. A country can raise its GDP by cutting down a forest or rebuilding after a disaster, activities that few would count as unambiguous gains. Out of this unease has grown a movement to measure something GDP ignores altogether: whether people's lives are actually going well.
The most direct way to find out, researchers decided, is simply to ask. Large surveys now invite people to rate their satisfaction with life on a numerical scale, or to report how much happiness, stress or anxiety they felt during the previous day. Critics were quick to object that such answers are hopelessly subjective — that one person's seven may be another's five, and that a reply can be swayed by the weather or the order of the questions. Defenders respond that, aggregated across thousands of respondents, these reports turn out to be surprisingly stable and to correlate with things one can observe from the outside, from health records to the judgements of friends. A self-report, on this view, is imperfect evidence but not worthless evidence, and it is the only kind we have of how a life feels from the inside.
Encouraged by such findings, a number of governments have begun to treat wellbeing as a legitimate object of policy. The small kingdom of Bhutan famously declared 'gross national happiness' a goal of state, and several wealthier nations have since started to collect wellbeing statistics alongside their economic ones, with some pledging to weigh them when deciding how to spend public money. Advocates argue that this corrects a long-standing distortion: if the ultimate aim of policy is to improve people's lives, then a government that measures only income is steering by the wrong instrument. Programmes that do little for output — support for mental health, say, or the preservation of green space — may deliver large gains in wellbeing that a purely economic accounting renders invisible.
Not everyone is persuaded that the enthusiasm is warranted. One line of objection is technical: if wellbeing cannot be measured with anything approaching the precision of economic data, then building policy upon it may simply replace a flawed number with a vaguer one. A deeper worry concerns comparison. Economic value can, at least in principle, be added up and traded off; it is far less obvious that one person's reported contentment can be meaningfully weighed against another's, or that gains and losses spread across a population can be summed into a single figure that means anything at all. To treat a satisfaction score as though it behaved like money, sceptics warn, is to mistake a convenient shorthand for a real quantity.
Perhaps the most unsettling challenge is philosophical rather than statistical. Human beings are strikingly good at adjusting to their circumstances, and people in genuinely harsh conditions often report levels of satisfaction that seem, to an outside observer, implausibly high. This capacity, sometimes called adaptation, cuts both ways for the wellbeing project. It can be read as a testament to human resilience; but it also raises the awkward possibility that a contented report may reflect lowered expectations rather than a good life. If a policy aimed at maximising reported happiness ended up encouraging people to want less rather than improving their conditions, it would have satisfied its stated goal while betraying its underlying purpose — a warning that what a measure rewards is not always what its designers intended.
The relationship between prosperity and happiness has itself proved contentious. An influential early study suggested that, beyond a certain point, richer countries were no happier than poorer ones, and that economic growth within a country did little for the contentment of its citizens over time — a finding that seemed to undercut the pursuit of growth for its own sake. Later work, drawing on larger datasets, has muddied the picture, with some economists reporting that satisfaction does keep rising with income, only more slowly, and others insisting that the original paradox holds once the right comparisons are made. The dispute is unresolved, and its outcome matters, for it bears directly on whether the wellbeing agenda genuinely points policy in a new direction or merely dresses up the old one.
What the argument ultimately exposes is a question that no amount of data can answer on its own: what, in the end, we take a good life to consist of. Wellbeing research can tell us how people rate their lives and what tends to move those ratings, and that is genuinely useful knowledge. It cannot, by itself, tell us how much weight such ratings deserve against other things we value — freedom, fairness, the meeting of basic needs — that people may not always report as happiness. The most careful advocates concede as much, presenting their measures not as a replacement for judgement but as one more consideration to be brought, cautiously, to bear on it. Read in that spirit, the counting of contentment need not crowd out everything else we care about; read carelessly, it easily could.
Reading Passage 3 has seven paragraphs, A–G. Which paragraph contains the following information? Write the correct letter, A–G.
- A Paragraph A
- B Paragraph B
- C Paragraph C
- D Paragraph D
- E Paragraph E
- F Paragraph F
- G Paragraph G
Do the following statements agree with the information given in Reading Passage 3? Write TRUE, FALSE or NOT GIVEN.
Choose the correct letter, A, B, C or D.
Answer the questions below. Choose NO MORE THAN THREE WORDS from the passage for each answer.