Grade 7 · English for Korean learners
Human history contains a remarkable amount of boiling, crushing, heating, and persuading stubborn materials to become something else. Industrial processes turn these actions into organised systems that can supply whole societies. Cheap paper helps ideas travel. Steel supports bridges. Steam engines supply power away from fast-flowing rivers. Synthetic fertiliser helps crops grow, while cement holds buildings together. These changes were not delivered by one clever machine acting alone. They depended on raw materials, skilled workers, infrastructure, and repeated control. Their benefits are immense, but so are some of their environmental costs.
In the News
Why a new zero-carbon UK steel plant offers hope and a headache — The Guardian, 28 May 2025. Proposed investment faced debate. Costs affect adoption.
‘We’re still in the 1970s with cement’: Norway plant to blaze carbon-free concrete trail — The Guardian, 12 August 2024. Carbon capture targeted cement emissions. Scaling remained challenging.
CF Industries forms JV with JERA, Mitsui for $4 billion low-carbon ammonia plant — Reuters, 8 April 2025. A planned facility targeted production beginning in 2029. Its design included carbon capture and storage. The announcement illustrates attempts to reduce the emissions associated with producing ammonia.
What do you think?
1] Why do identical objects need consistent materials?
2] How could cheap writing material change society?
3] Why does a wet sheet become stronger when dry?
4] What makes a metal useful for a bridge?
5] Why might removing an ingredient improve a material?
6] How can heat produce movement?
7] Why would a factory need a steady power supply?
8] What happens when production grows faster than transport?
9] Why can a useful chemical become harmful in excess?
10] How could air help feed crops?
11] Why does a building material need time to harden?
12] What makes repairing an object better than replacing it?
13] How can one improvement create another problem?
14] Why should a factory measure temperature repeatedly?
15] What might go wrong when a small experiment becomes enormous?
16] Why do workers need protective systems?
17] How could waste from one process serve another?
18] Why might recycling require sorting?
19] Who should pay for pollution?
20] What should count as progress besides making more objects?
Did You Know?
1] Cai Lun is traditionally credited with improving papermaking in China in 105 CE; paper existed earlier.
2] The Bessemer process was introduced in 1856.
3] The first industrial Haber–Bosch ammonia plant opened at Oppau in 1913.
4] Nineteenth-century farmers imported guano, or seabird droppings, as fertiliser; useful nitrogen had a distinctly unglamorous source.
Vocabulary
- raw material — 원료
- fibre — 섬유
- pulp — 종이의 원료 섬유 덩어리
- drain — 물을 빼다
- press — 눌러 압착하다
- sheet — 얇은 장
- print — 인쇄하다
- literacy — 읽고 쓰는 능력
- ore — 광석
- coke — 코크스
- impurities — 불순물
- molten — 녹은 상태의
- brittle — 잘 깨지는
- tough — 잘 부러지지 않는
- batch — 한 번에 처리하는 양
- boiler — 증기 발생 장치
- pressure — 압력
- condense — 응축하다
- shaft — 회전축
- precision — 정밀도
- scale — 규모
- vessel — 용기
- fertiliser — 비료
- runoff — 빗물 등에 씻겨 흐르는 물질
- kiln — 고온 가마
- limestone — 석회석
- clinker — 시멘트의 중간 소성물
- aggregate — 콘크리트의 모래와 자갈
- quality control — 품질 관리
- supply chain — 공급망
Glossary
Industrial process — An organised method transforms materials or energy. It can operate repeatedly at large scale. Control makes output dependable. 산업 공정.
Cellulose — Cellulose is a structural substance in plant cell walls. Its fibres help form paper. It also occurs in wood and cotton. 셀룰로스.
Steel — Steel is an iron-based alloy containing controlled carbon. Other elements can change its properties. It supports many structures and tools. 강철.
Reduction — In metal extraction, reduction can remove oxygen from metal compounds. A reducing substance enables the change. This produces metal from suitable ores. 환원.
Steam engine — Steam pressure produces mechanical movement. Heat provides the energy source. Different designs manage steam in different ways. 증기 기관.
Catalyst — A catalyst speeds a chemical reaction. It provides an easier reaction route. It is not consumed overall in the reaction. 촉매.
Haber–Bosch process — Nitrogen and hydrogen react to produce ammonia. High pressure and a catalyst support production. Industrial control enables large output. 하버–보슈 공정.
Ammonia — Ammonia contains nitrogen and hydrogen. It is an important chemical feedstock. Many fertilisers are made from it. 암모니아.
Cement — Cement is a binding material. It reacts with water and hardens. It is an ingredient of concrete. 시멘트.
Hydration — A material reacts chemically with water. Cement hydration creates binding products. Hardening is more than simple drying. 수화 반응.
Paper: Making Information Cheap to Copy
Paper forms when plant fibres are spread in water, drained into a sheet, pressed, and dried. Many fibres contain cellulose, which helps provide strength. As water leaves, fibres come into close contact and bond. The resulting sheet is light, flexible, and suitable for writing or printing. Raw materials and processing affect its texture and durability. Paper existed in China before Cai Lun, who is traditionally credited with improving papermaking in 105 CE. Invention here was a developing craft rather than one person’s sudden discovery of a wet rectangle. Better methods gradually made writing material easier to produce and use.
1] How do fibres become a paper sheet?
2] Why is papermaking history more complex than one inventor?
Producing paper at larger scale required reliable preparation of pulp, controlled sheet formation, and efficient drying. Industrial machines later made continuous sheets instead of relying only on individual hand-made sheets. Consistent thickness and surface quality helped printers handle material predictably. Water, energy, and transport were essential alongside the machinery. A mill needed fibres coming in and finished paper going out. Production costs fell when the system worked efficiently, though working conditions and pollution required attention. Scale therefore involved more than making a larger frame. It depended on organising a repeated flow of materials while controlling quality across an enormous length of sheet.
1] Why does consistent thickness help printing?
2] What resources does a paper mill need besides machinery?
Printing turns a prepared design into many copies. Movable type allowed printers to rearrange characters rather than prepare a whole new carved page for every text. East Asian printing traditions included early movable type, while Gutenberg’s European system developed in the fifteenth century. Cheap paper and reliable printing worked together to expand access to books, notices, and records. More copies could spread scientific findings and political arguments. They could also spread errors remarkably efficiently. The machine did not check whether a sentence was true. Literacy, distribution, and freedom to publish influenced how strongly the technical change affected each society.
1] How did movable type support copying?
2] Why did printing not guarantee accurate information?
Paper production still has environmental trade-offs. Fibre sourcing can affect forests and land use, while processing consumes water and energy. Some methods use chemicals to separate fibres or improve appearance. Recycling returns used fibres to production, but sorting and cleaning remain necessary. Repeated processing can shorten fibres, so every sheet cannot be recycled indefinitely into identical new paper. Contamination also limits useful recovery. Responsible systems combine suitable sourcing, efficient production, and appropriate reuse. Digital communication changes some demand but has its own material and energy needs. Comparing options requires a defined use rather than assuming one medium is environmentally superior in every situation.
1] Why can paper not be recycled endlessly into identical sheets?
2] What makes fibre sourcing environmentally important?
Steel: Controlling an Extremely Useful Metal
Iron ore often contains iron chemically combined with oxygen. Extracting useful iron requires changing those compounds. In a blast furnace, hot gases and carbon-based materials support reduction, removing oxygen while supplying heat. Coke also helps maintain a structure through which gases can flow. The resulting molten iron usually contains too much carbon and other impurities for many applications. Further processing changes its composition. The furnace is therefore part of a larger sequence rather than a machine that directly produces every finished metal object. Understanding chemical extraction helps explain why mining, fuel, heat, and emissions are all connected to ordinary steel products.
1] Why must iron ore undergo chemical change?
2] Why does molten iron need further processing?
Steel is an iron-based alloy with carefully controlled carbon content and often other elements. Small composition changes can strongly alter hardness, toughness, and resistance to corrosion. Too much carbon can make some iron materials brittle, while suitable processing produces steel useful for tools and structures. Heat treatment and shaping also affect internal structure. The same broad material family can therefore serve a kitchen utensil, a railway track, or a bridge. Choosing steel means matching properties to a job, not merely selecting something described as strong. A hard cutting edge and a structure that resists sudden fracture require different balances of characteristics.
1] Why does carbon content matter?
2] Why do different applications need different steel properties?
Henry Bessemer introduced a process in 1856 that blew air through molten iron to remove excess carbon and some impurities. Oxidation supplied heat as well as changing composition, allowing large batches to be processed quickly. The method had important limits, including difficulties with some ore compositions. Other processes later improved control and expanded useful materials. Cheaper steel supported railways, machinery, and larger structures, but these developments also required design, labour, and investment. A fast process was historically important because it changed the amount and cost of available material. It did not make every earlier metallurgical problem disappear in one dramatic puff of air.
1] How did the Bessemer process change molten iron?
2] Why did cheaper steel affect more than metalworking?
Modern steelmaking includes basic oxygen furnaces and electric arc furnaces. Electric arcs provide intense heat that can melt scrap steel and other suitable feedstock. Recycling avoids some requirements of extracting entirely new iron, but scrap quality and unwanted elements still matter. Electricity’s source affects emissions. Hydrogen-based direct reduction offers another route to lower emissions when hydrogen is produced with low emissions, although costs and infrastructure remain challenges. Different processes suit different material supplies and products. Calling all electrically made steel clean oversimplifies the system. Useful assessment examines energy, feedstock, product quality, and whether the proposed process can operate reliably at scale.
1] How can electric arc furnaces use scrap?
2] Why does the electricity source affect environmental performance?
Steam Power: Turning Heat into Work
Steam engines use heat to produce steam and use pressure changes to drive movement. Early engines helped pump water from mines, allowing work in places where flooding restricted access. Thomas Newcomen’s engine, first operating in 1712, used steam condensation to create a pressure difference that moved a piston. Its action depended partly on atmospheric pressure rather than simply steam pushing with high pressure. This distinction shows why the exact mechanism matters. Later designs improved performance and expanded applications. Heat became a controllable source of mechanical work, reducing dependence on the immediate availability of wind, flowing water, or large teams of animals.
1] What problem did early steam engines address?
2] How did condensation help a Newcomen engine work?
James Watt’s separate condenser reduced the repeated heating and cooling of the main cylinder. He patented the idea in 1769, contributing to major improvements in fuel use. The condenser allowed steam to cool in a separate part while the cylinder remained hotter. This illustrates a general engineering principle: avoid wasting energy on changes that do not help the desired output. Later mechanisms supported useful rotary motion for machinery. Watt did not invent every part of steam power, and other engineers contributed important improvements. The history involves accumulated changes, commercial organisation, and practical manufacturing rather than a single genius supplying the entire Industrial Revolution.
1] Why did a separate condenser reduce waste?
2] Why should steam-engine history include several contributors?
Steam power could drive factory machinery through rotating shafts and belts. A central engine supplied movement to several machines, allowing production to be organised away from particular water-powered sites. This changed where some factories could operate and how work was coordinated. It also created risks from exposed moving equipment and dependency on one power source. Reliable construction required precision: poorly fitted parts leaked, wore quickly, or failed. Better machine tools supported better engines, which in turn supplied power for manufacturing. Industrial change therefore formed interacting systems. A useful engine needed suitable materials, skilled workers, fuel supplies, maintenance, and machinery worth driving.
1] How did central power reach factory machines?
2] Why did precision manufacturing matter for engines?
Boilers contain heated water and steam under controlled conditions. Excessive pressure, defects, or inadequate water management can cause dangerous failures. Safety valves, inspection, and trained operation became essential as steam systems spread. Fuel consumption also produced air pollution and carbon dioxide, depending on the fuel. Steam technology enabled transport and production while creating costs that affected workers and surrounding communities. Modern power stations still often use steam turbines, though the heat source and equipment differ from early engines. The lasting principle is conversion from heat to mechanical work. Progress depends on managing hazards and losses as well as increasing the available power.
1] Why are boiler safety systems necessary?
2] What principle connects early engines with many modern power stations?
Ammonia, Cement, and the Next Industrial Changes
Plants need nitrogen to build important biological molecules, but most cannot use nitrogen gas directly from the air. The Haber–Bosch process combines nitrogen with hydrogen to produce ammonia, a starting material for many fertilisers. Industrial production began at Oppau in 1913 after major work on laboratory chemistry and scale-up. Typical operation uses several hundred degrees Celsius, high pressure, and a catalyst. Exact conditions depend on the plant. Strong pressure vessels and careful gas handling are essential. The process made large supplies of usable nitrogen possible. Air suddenly became a raw material for agriculture, although extracting its useful nitrogen required considerable engineering effort.
1] Why can most plants not directly use atmospheric nitrogen?
2] What conditions support industrial ammonia production?
Synthetic fertiliser can increase crop yields where nutrients limit growth. It works alongside soil management, water, crop choice, and farming skill; adding more material is not a universal solution. Producing ammonia consumes energy, and conventional hydrogen production commonly uses fossil fuels. Excess fertiliser can leave fields in runoff, contributing to nutrient pollution and oxygen loss in water. Some nitrogen also reaches the atmosphere as nitrous oxide, a powerful greenhouse gas. The same chemistry that supports food production can therefore create environmental harm when poorly managed. Improved production and careful application address different stages of the problem and should not be treated as interchangeable fixes.
1] How can fertiliser improve yields?
2] Why must production and application impacts be addressed separately?
Portland cement production heats limestone and other materials in a kiln to form clinker, which is then processed into cement. Heating limestone releases carbon dioxide through chemical change, in addition to emissions from supplying heat. Cement is not the same as concrete. Concrete combines cement, water, and aggregate such as sand and gravel. Cement hydration creates binding products that hold the mixture together. It hardens through reactions rather than merely drying like wet clothes. This explains why moisture conditions during curing matter. The material’s usefulness comes with a major emissions challenge because both energy supply and the chemistry of production require attention.
1] How does cement differ from concrete?
2] Why does cement production release carbon dioxide beyond fuel burning?
Improving industry requires examining complete processes. Lower-emission electricity, material recycling, alternative feedstocks, and carbon capture can address different sources of impact. Carbon capture separates some carbon dioxide for storage, but performance, energy needs, transport, and secure storage must be assessed. A laboratory method also needs dependable scale-up before it can replace a major industrial supply. Quality control checks whether output meets required properties, while supply chains connect raw materials with users. Future progress should include cleaner production, useful products, worker safety, and reduced waste. Producing more is one measurable result. Producing what society needs with fewer avoidable costs is a broader achievement.
1] What must be assessed in carbon capture?
2] Why is successful scale-up more than a laboratory demonstration?
Homework
Writing tasks
1] Write approximately one page. Explain how cheap writing material could change access to information.
2] Write approximately one page. Describe why fibre preparation and drying affect paper quality.
3] Write approximately one page. Argue how printing can spread both knowledge and errors.
4] Write approximately one page. Explain why steel composition must match its application.
5] Write approximately one page. Describe why a larger industrial process needs more than a larger container.
6] Write approximately one page. Explain how reducing wasted heating improved steam power.
7] Write approximately one page. Discuss why worker safety is part of technical progress.
8] Write approximately one page. Explain how useful nitrogen can create environmental harm when poorly managed.
9] Write approximately one page. Describe why cement hardening is more than drying.
10] Write approximately one page. Propose criteria for judging a cleaner industrial process, including quality, cost, and safety.
Debate topics
1] Should governments support early low-emission industrial plants?
Side A — Yes, because: 1) early costs are high; 2) learning benefits later projects; 3) shared emissions benefits justify support.
Side B — No, because: 1) public funds are limited; 2) some projects may fail; 3) subsidies may favour unsuitable technology.
2] Should products contain more recycled material when technically suitable?
Side A — Yes, because: 1) extraction can decrease; 2) waste gains value; 3) supply can become more circular.
Side B — No, because: 1) contamination complicates quality; 2) processing needs energy; 3) some applications need carefully controlled material.
3] Should industrial success include mandatory environmental measures?
Side A — Yes, because: 1) pollution affects others; 2) efficiency alone misses harm; 3) common rules support accountability.
Side B — No, because: 1) measurement is costly; 2) small firms face burdens; 3) unsuitable targets may shift production elsewhere.
Test questions
Answer the following questions in full sentences. If you don’t know the right answer, add a (?) mark, and later we can look at it together.
1] How is a paper sheet formed?
2] What does cellulose contribute?
3] Why is Cai Lun’s role qualified?
4] What makes continuous paper production useful?
5] How did movable type help printing?
6] Why does recycling paper have limits?
7] What must happen to iron compounds during extraction?
8] What is coke’s role in a blast furnace?
9] How can composition change steel properties?
10] What did the Bessemer process do?
11] How does an electric arc furnace heat material?
12] What problem did early steam engines address?
13] How did condensation move an early engine’s piston?
14] Why was Watt’s separate condenser useful?
15] Why do boilers need safety controls?
16] What gases produce ammonia?
17] Why are catalysts and pressure important?
18] How can excess fertiliser damage water?
19] How does cement differ from concrete?
20] Why must cleaner processes be evaluated at scale?
Teaching illustrations and similes
1] Paper fibres — A loose net becomes a sheet when fibres bond; chemical interactions matter as well as contact.
2] Printing — Reusable letter stamps make many messages; arranging and distributing them still takes work.
3] Steel composition — A recipe changes texture; metallurgy also depends on heat and internal structure.
4] Reduction — Removing oxygen frees iron from certain compounds; atoms are rearranged rather than simply peeled away.
5] Bessemer processing — Air changes a molten mixture; it triggers reactions rather than merely cooling the metal.
6] Separate condenser — Avoid repeatedly warming and chilling one room; a real engine uses pressure and phase changes.
7] Factory power — One central drive supplies many branches; mechanical connections introduce losses and hazards.
8] Catalyst — A better route lowers a barrier; it does not supply unlimited energy.
9] Fertiliser — Supplying a missing ingredient helps growth; excess can harm the wider environment.
10] Scale-up — Cooking for a town differs from cooking one meal; heat transfer and equipment limits also change.
