IELTS Academic Reading Practice Test 142

In the early 1990s, the factories of the Toyota group faced a problem of scale. Components and sub-assemblies moved through production lines at speed, and each one had to be identified so that the right part reached the right place at the right time. The conventional barcode, the striped label that had by then become familiar on grocery packaging, was no longer adequate. A standard barcode holds only a limited number of characters, usually a dozen or so digits, and it must be read by a beam of light travelling across it in a single direction. If the label was creased, printed on a curved surface or scanned at an awkward angle, the reader might fail.

The task of finding a better system fell to Masahiro Hara, an engineer at Denso Wave, a company within the Toyota group that supplied components and automatic identification equipment. Hara and a small team began work in 1992. Their aim was a code that could hold far more information than a barcode, could be read from any direction in a fraction of a second, and would survive the rough conditions of a workshop.

The solution they reached in 1994 was a square grid of black and white modules, the individual squares that make up the pattern. Unlike a barcode, which stores data only along its length, this code carries information both horizontally and vertically, which is why it can hold so much more. A symbol of the largest standard size can store more than 7,000 numeric characters, or about 4,000 letters of the alphabet, against the handful held by a conventional barcode.

Three large squares, one in each of three corners, are the feature that makes the code so easy to read. These finder patterns, as they are called, look the same from whatever angle the code is viewed, so a scanner can locate the symbol, work out its orientation and correct for perspective in a single operation. Smaller alignment patterns scattered across the grid allow the reader to compensate for distortion when the code is printed on a curved or flexible surface. Because the code can be decoded in any orientation, a user no longer has to line a beam up precisely along a row of stripes.

The design also includes a degree of redundancy. Data is encoded with an error-correction method, a mathematical technique that adds extra information so that the original message can be rebuilt even when parts of it are missing or misread. At the highest of the four correction levels, up to about 30 per cent of the symbol can be obscured – by dirt, a scratch or a printed logo – and the code will still work. This is why a symbol can carry a company logo in its centre without becoming unreadable.

The name chosen for the invention, Quick Response, referred to the speed with which it could be decoded rather than to anything the user had to do. Denso Wave applied for patents, but the company later announced that it would not exercise its rights over the code, and the specification was published so that anyone could use it free of charge. That decision, more than any technical feature, helps to explain why the square pattern spread around the world.

At first the code did what it had been designed to do. Factories in Japan attached it to parts and to the paperwork that travelled with them, making possible the detailed tracking of production. The next stage came with the mobile telephone. From around 2002, Japanese handsets were sold with software that could read a code using the built-in camera, and the patterns began to appear on posters, business cards and advertisements. For a while this was a largely Japanese phenomenon; elsewhere the technology remained a niche tool for industry and logistics.

The turning point was the smartphone. Once a phone could download an application, and later use its camera without one, every owner had a reader in their pocket. Apple added reading to the iPhone's camera in 2017, and Android devices had offered similar functions. Payment systems in China built their checkout processes around the code, with customers scanning a pattern displayed by the shop rather than one displayed by the customer. The advantage was cost: a merchant needed no card terminal, only a printed sheet of paper.

The pandemic of 2020 gave the code a further push. Restaurants replaced printed menus with a square on the table, governments used codes to record entry to buildings, and public health authorities built contact-tracing systems in which each user's phone displayed a code of its own. In many countries a code became the routine means of proving vaccination status or booking a test. Some of these uses have faded since, but others have proved durable, and the pattern is now so common that it is rarely noticed.

Hara's team also produced a smaller version, the Micro QR code, in 1999. It needs only one finder pattern and fits into far less space, though it holds less data. Later standards added further variants, including codes designed for very small items and for industrial marking. More than thirty years after it was introduced, the original design has needed remarkably little revision, a sign that its inventors solved the problem at the first serious attempt.

Global production of plastic now exceeds 400 million tonnes a year, and the OECD has estimated that less than one tenth of the waste is recycled. The method that dominates recycling is mechanical. Used plastic is sorted by type and colour, washed, shredded and melted, then remoulded into pellets or new products. The process is cheap and well understood, but it has limits. Mixed and multilayer packaging is difficult to separate, and contamination by food or other plastics lowers the quality of the output. More fundamentally, every time a polymer is melted its long chains break, so the material becomes shorter and less strong. After two or three cycles the plastic is often downcycled into a bench or a bin liner, and eventually incinerated or buried.

Chemical recycling, also called feedstock recycling, takes a different approach. Instead of melting plastic and reshaping it, these processes break the polymer chains apart, converting the material into monomers, oils or gases that can be used to make new plastic or, in some cases, fuel. In principle this allows contaminated or mixed waste to be treated, and it yields a product indistinguishable from virgin material. The promise is considerable; the difficulties are equally real.

A polymer is a long molecule built from repeating units called monomers, joined end to end. The bonds holding those units together determine how easily a plastic can be taken apart. In PET, the polyester used in drinks bottles and clothing fibres, the units are linked by ester bonds, which can be broken by water, alcohols or acids. The polyolefins – polyethylene and polypropylene, which together account for the largest share of plastic production – have a backbone of carbon-carbon bonds. These are strong and non-polar, and offer no convenient chemical handle for a reagent to attack.

The most established chemical route is depolymerisation, in which PET is broken back into the monomers from which it was made: ethylene glycol and either terephthalic acid or a closely related compound, depending on the reagent used. Treating the plastic with methanol under heat and pressure, a process known as methanolysis, is the basis of several commercial plants. Because the polymer is destroyed rather than merely softened, the process can accept coloured bottles, attached labels and a degree of contamination, and the monomers can be purified and repolymerised into food-grade plastic. Plants are now operating in Europe and Asia, though most are modest in size.

Polyolefins cannot be depolymerised in the same simple way, so they are usually treated by pyrolysis. Waste plastic is heated to between about 400 and 600 °C in a vessel from which oxygen has been excluded, so that it does not simply burn. The heat causes the long chains to crack into shorter molecules, producing a gas, a solid char and a dark liquid known as pyrolysis oil. That oil is a complex mixture, but it can be fed into a steam cracker, the equipment that normally turns petroleum-derived naphtha into ethylene and propylene, and so back into plastic. The quality of the oil, and the difficulty of removing oxygen and nitrogen compounds from it, remain obstacles.

Gasification pushes the temperature higher still and admits a controlled amount of oxygen or steam. The plastic is converted almost entirely into synthesis gas, a mixture of carbon monoxide and hydrogen, which can be used to make methanol or liquid hydrocarbons through well-established industrial chemistry. Gasification can tolerate almost any mixture of waste, which makes it attractive for the residues that no other process can handle. Its drawback is energy: the process is demanding, and much of the chemical energy in the plastic is lost as heat.

Biological methods are newer. In 2016 a team in Japan reported the discovery of a bacterium, Ideonella sakaiensis, living on PET waste at a recycling site and producing an enzyme capable of breaking the polymer down. Since then, researchers have engineered faster and more stable versions of similar enzymes. In 2020 a French company, Carbios, reported an engineered enzyme that could depolymerise PET within hours at a temperature above 70 °C. Enzymes work in water at moderate temperatures and avoid the need for aggressive chemicals, but they are highly specific: the carbon-carbon bonds of polyolefins have so far resisted biological attack.

Economics and policy shape what is actually built. A chemical plant needs a large, consistent supply of sorted waste, and pyrolysis oil must compete on price with fossil naphtha. Most plants are still small, and some produce fuel rather than new plastic, which campaigners argue should not count as recycling. Accounting rules allow a company to claim recycled content through a 'mass balance' system, in which the output of a chemical process is credited to whichever product the buyer prefers, even if the plastic itself contains no recycled molecules. Regulation is nonetheless pushing investment upwards: European rules require plastic bottles to contain at least 25 per cent recycled material by 2025, and 30 per cent by 2030.

Design may eventually matter more than disposal. At the Lawrence Berkeley National Laboratory in California, researchers have made a plastic called PDK whose bonds can be broken by soaking it in acid, allowing the monomer to be recovered cleanly and repeatedly. Others are developing polymers that come apart when heated rather than degrading into a mixture. Such materials would make recycling far easier, but they must compete on cost and performance with plastics refined over seventy years. Chemical recycling is likely to remain one tool among several rather than a complete answer.

Cyberbullying – repeated hostile behaviour directed at a person through phones, computers and social media – deserves to be examined rather than assumed to be a crisis. My own view is that the harm it causes is entirely real and sometimes severe, but that the widespread assumption it is a wholly new kind of cruelty, brought into existence by technology, has distorted both public discussion and the remedies that schools and governments have chosen. Technology has altered the reach and durability of bullying far more than its nature.

Measurement is the first difficulty. Estimates of how many young people have been bullied online vary enormously, from a few per cent to more than half, and the variation reflects the way the question is asked rather than any real difference between countries. Does a single cruel message count, or must behaviour be repeated? Must there be an imbalance of power between the parties? A meta-analysis of studies from many countries that applied reasonably strict definitions arrived at an average of roughly fifteen per cent of adolescents, which is high enough to command attention without supporting the language of epidemic that often surrounds the subject.

Equally important is the overlap with ordinary bullying. Study after study finds that most children who are harassed online are also harassed face to face, and that the same individuals tend to be involved in both settings. Those most at risk are usually already vulnerable, whether because of their appearance, their sexuality, a disability or a difficult home life. The image of a child who is perfectly happy at school but tormented at night by strangers is not typical. If that is right, a good deal of what is called cyberbullying is old behaviour in a new setting.

What is genuinely new is a matter of degree. Before the internet, a bullied child could usually count on being safe at home; now the insult follows them into the bedroom. A cruel photograph or a rumour can be copied, forwarded and stored indefinitely, so that humiliation acquires a permanence it never had before. The audience is larger and, crucially, more visible to the victim: a post can be seen by hundreds of people who never witness the distress it causes. And because the perpetrator is physically distant, the ordinary human signals of distress – a face, a voice, tears – are absent. Psychologists call the resulting loss of restraint disinhibition, and it lowers the threshold for cruelty in people who would not behave in the same way in a corridor.

Anonymity is usually cited as the defining feature, and here the popular account is too simple. Much abuse takes place between people who know one another, in classes and friendship groups, under real names. Where accounts are anonymous, platforms hold data that identifies them, and a police investigation can often establish who was behind a profile. None of this is much comfort to a frightened child at one in the morning, but it matters for how the problem is framed: the difficulty lies less in the impossibility of finding offenders than in the slowness of the process and the reluctance of victims to report.

What of the consequences? Research consistently finds associations between being bullied online and anxiety, depression, poor sleep and self-harm. The causal question is harder. Children who are already depressed may be more likely to be targeted, and more likely to spend time in the places where abuse occurs. Longitudinal studies point towards a genuine contribution from bullying rather than a purely coincidental link, but the effect is entangled with everything else in a child's life. The reasonable conclusion is that the harm is serious, and that the precise mechanism matters less than what is done about it.

Remedies are where the argument becomes practically important. Schools have adopted anti-bullying programmes, some of them carefully evaluated. A systematic review of school-based interventions found that they reduced cyberbullying by roughly a tenth, and victimisation by a little more. That is worth having, but it is modest. The most promising element appears to be work with bystanders, since most incidents have an audience, and the audience's response helps to determine whether the behaviour continues. Lessons in digital literacy, by contrast, have been promoted energetically with rather little evidence that they alter how pupils behave.

Platforms, in my view, have escaped too lightly. The claim that a social network is merely a conduit, like a telephone line, is unsustainable when its design determines how easily a message can be forwarded, how large an audience can be assembled and how prominent a hostile reply becomes. Small changes to defaults – limiting who may comment, making reporting simpler, slowing the spread of a post that many users have flagged – reach more children than any classroom lesson. Age limits and verification would help too, though the technical difficulties are real.

My position, then, is that cyberbullying is neither a moral panic nor an unprecedented catastrophe. It is bullying, amplified by tools that extend its reach, remove its boundaries and make its traces last. Criminal prosecution is a blunt instrument that rarely serves a young victim well. What works is duller and harder: a school culture in which cruelty is uncool, platform design that does not reward it, and, above all, adults who take a child's account seriously the first time it is offered.