Natural Rubber- An exotic material
A. Today, we take modem materials very much for granted, without knowing their origin or realising their versatility. Rubber, for example, is a vital component of cars, supplying traction between the wheels and the road, as well as sealing oil and fuel from leakage and absorbing unwanted vibrations from the engine. Rubber also supplies us with many domestic items (toy balloons, water bottles, condoms, carpet underlay, mattresses and cushioning), office products (rubber bands, erasers) and articles of sports and recreation (footballs, golf balls, tennis balls, etc.). But where does rubber come from?
B. Natural rubber was discovered during the various invasions of South America by the Spanish conquistadors in the 15th century. The material, made simply by drying out the sap of a native tree, Hevea brasiliensis, was first spotted by Columbus in the West Indies in the 1490s, where it was used to make balls. It was also made into bags for carrying liquids by moulding flexible rubber sheet into the desired shape. Rubber was clearly a material well known to native cultures, and recent discoveries of its use in ancient ceremonies are hardly surprising.
C. Despite its early discovery by the Spanish, it was not until about 1730 that rubber was introduced into Britain, and not until 1791 that its use for the mackintosh (the rubberised raincoat) was introduced. In 1770 Joseph Priestley, who also discovered oxygen, noticed that rubber erases pencil marks. Despite this serendipitous finding, it still took some time before the material was to find widespread application. One reason for this was its deterioration with time, degrading in air to a sticky unmanageable mess. That was to change dramatically with the invention of ‘vulcanisation’, when, in 1834, Charles Goodyear found that cooking the material with raw sulphur stabilised it and stiffened products manufactured from the substance.
D. This discovery opened the way to pneumatic tyres for early vehicles such as carriages (travel in which was rather painful owing to the rigid wheels and rough roads then in existence). The first patent for a tyre dates from 1846, when Robert Thompson announced the pneumatic tyre, a great advance for wheeled traffic. The key to the idea is the cushion provided by the air pocket, the pressure of which can be varied to suit the user. The invention languished, perhaps because of problems with containing the inevitable leaks of air from the many inner tubes. However, solid rubber tyres were subsequently adopted, with much reduced cushioning.
E. At the same time, vulcanised rubber came to be used for an increasing number of products, such as galoshes or Wellington boots and improved mackintoshes, where rubber was combined with textile to make a waterproof fabric. The growing demand for natural rubber made it a commodity product, yet only supplied by one area in the world - Brazil. As a result, the price soared, creating rich entrepreneurs, who essentially exploited natives to collect the raw latex from the rainforest. But since the tree could potentially be grown in any tropical climate, why not collect seedlings and transplant to other countries?
F. Intensive efforts were made at Kew Gardens to raise healthy plants from seeds collected by Sir Henry Wickham in Brazil in 1876. The young trees raised in the tropical greenhouse at Kew were shipped to Ceylon and Malaysia to form the nucleus of large plantations. Those countries were able to meet the rising demands of the rubber industry, and the price of raw rubber fell dramatically.
G. In 1888, over forty years after Thompson’s invention of the pneumatic tyre, John Dunlop, a Belfast vet, responded to a request from his young son for better tyres for his trike. When ridden over the rough cobbles of Belfast's streets, solid rubber tyres just could not give a comfortable ride. Various rubber tubes were used by vets, and Dunlop re-invented the pneumatic tyre by fitting a wheel with an inflated rubber tube protected by a heavier outer cover. After much experimentation, the world’s first bicycle emerged.
H. Dunlop’s first patent to protect the invention was inevitably invalid because of Thompson’s prior parent, hut he went on to invent the valve and numerous other components which were proved valid. Those inventions were the base on which he and others built the bike tyre industry, which brought cycling into a new era for everyone. It was an era when industrial progress had created newfound wealth and leisure time for millions. As with any new and fundamental invention, the idea was taken up by others, in particular by Michelin in France (1896), to develop a much heavier-duty device, the car tyre.
I. Today a wide range of synthetic rubber is available to designers, many for specialty tasks requiring, for example, very high or low temperatures. Yet natural rubber is still a valuable international commodity, helping many developing countries earn useful hard currency. The technology of processing the raw rubber has improved greatly over the years, but the basics still remain the same as they were when Kew Gardens selected the best plants for cloning and transplanting over one hundred years ago.
Dunlop's comfortable tyre
Dunlop originally devised a new tyre to make his son's trike more comfortable. He was familiar with different types of rubber as he used them in his . A lighter inner tube filled with air was fitted inside a heavier rubber outer . Unfortunately, he could not patent it due to a between his and an earlier invention. It was the of the valve which proved his success. Around this time people had more and and so cycling was taken up by the masses.
What is the name of the method which prevents rubber from deteriorating?
What happened when the demand for rubber greatly outstripped supply?
In which tropical countries were the new supplies of rubber trees grown? and
AI explanationShows the answer. Tap to open.
Question Focus: Synonym match - summary says 'used them' and passage explains Dunlop's professional work
Correct Answer: practice
Why this is correct: The passage explains that Dunlop was a vet and regularly used rubber tubes in his work. That means he knew rubber from his practice, which fits the summary sentence exactly.
Passage Reference: ride. Various rubber tubes were used
Common Mistake: Students may write job or work, but those words do not appear in the passage. You must copy the exact word from the text. This is a synonym trap.
Paraphrasing: Passage: 'used by vets' = Summary: 'used them in his practice'
Tips: When the summary refers to someone's job, check if the passage uses a specific noun for that profession.
Key Vocabulary:
- vet = animal doctor
- practice = professional work
Question Focus: Synonym match - summary says 'outer' and passage uses a technical noun
Correct Answer: casing
Passage Reference: c tyre by fitting a wheel with an inflated rubber tube protected by a heavier outer cover.
Why this is correct: The passage describes an inflated tube protected by a heavier outer cover. The summary paraphrases this as an outer casing, which is the correct passage word.
Common Mistake: Students may write cover, which looks correct but does not match the summary wording. The summary requires casing. This is a partial truth trap.
Paraphrasing: Passage: 'outer cover' = Summary: 'outer casing'
Tips: If the summary already paraphrases, look for the closest matching noun in the passage.
Key Vocabulary:
- casing = outer layer
- tube = hollow rubber pipe
Question Focus: Synonym match - summary explains why the patent failed
Correct Answer: similarity
Passage Reference: ed. H. Dunlop's first patent to protect the invention was inevitably invalid because of Thompson's prio
Why this is correct: The passage says Dunlop's patent was invalid because of Thompson's prior patent. This means the inventions were too similar, so similarity explains the reason clearly.
Common Mistake: Students may write copy or patent, but the gap explains the relationship, not the object. This is a context shift trap.
Paraphrasing: Passage: 'prior patent' = Summary: 'similarity between his and an earlier invention'
Tips: Look for cause-and-effect language like 'because of' or 'due to' to find the right noun.
Key Vocabulary:
- prior = earlier
- patent = legal protection
Question Focus: Synonym match - summary highlights what made Dunlop successful
Correct Answer: addition
Why this is correct: The passage explains that Dunlop later invented the valve, and this invention was valid. The summary paraphrases this as the addition of the valve.
Common Mistake: Students may write invention, which is true but too general. The summary focuses on adding something new. This is a partial truth trap.
Paraphrasing: Passage: 'invent the valve' = Summary: 'addition of the valve'
Tips: When a summary uses an abstract noun, look for an action verb in the passage.
Key Vocabulary:
- valve = air control part
- addition = something added
Question Focus: Synonym match - summary refers to social change
Correct Answer: money
Passage Reference: eryone. It was an era when industrial progress had created newfound wealth and leisure time for millions.
Why this is correct: The passage says people had newfound wealth, which means more money. This explains why cycling became popular.
Common Mistake: Students may write wealth, but the summary already paraphrases it. You must choose the word that fits the summary gap. This is a paraphrase trap.
Paraphrasing: Passage: 'newfound wealth' = Summary: 'more money'
Tips: Words like 'wealth' are often paraphrased as simpler everyday words in summaries.
Key Vocabulary:
- wealth = money and resources
- era = period of time
Question Focus: Synonym match - summary continues the social explanation
Correct Answer: life
Passage Reference: eryone. It was an era when industrial progress had created newfound wealth and leisure time for millions.
Why this is correct: The passage mentions increased leisure time, meaning people had more free life outside work. This supports why cycling spread widely.
Common Mistake: Students may write time, which repeats the passage but does not fit the summary wording. This is a grammar fit trap.
Paraphrasing: Passage: 'leisure time' = Summary: 'more life'
Tips: When two gaps are linked with 'and', they usually have the same grammar form.
Key Vocabulary:
- leisure = free time
- masses = many people
Question Focus: Direct factual answer - naming a process
Correct Answer: vulcanization
Passage Reference: s. That was to change dramatically with the invention of 'vulcanisation', when, in 1834, Charles Goodyear found that cooking the material with raw sulphur stabilised it and stiffened products manufactured from the substance.
Why this is correct: The passage clearly names vulcanisation as the method that stopped rubber from deteriorating. This directly answers the question.
Common Mistake: Students may explain the process instead of naming it. The question asks for the name, not a description. This is a wrong focus trap.
Paraphrasing: Passage: 'vulcanisation' = Question: 'method which prevents rubber from deteriorating'
Tips: When a question asks for a name, look for a technical term in the passage.
Key Vocabulary:
- deteriorate = break down
- stabilise = make stable
Question Focus: Cause-and-effect understanding
Correct Answer: soared prices
Passage Reference: zil. As a result, the price s
Why this is correct: The passage explains that demand increased but supply was limited, and the price soared. The summary restates this as soared prices.
Common Mistake: Students may write price increased, which changes the wording. You must copy the exact words from the passage. This is a synonym trap.
Paraphrasing: Passage: 'the price soared' = Summary: 'soared prices'
Tips: If the question asks 'what happened', look for a clear result sentence in the passage.
Key Vocabulary:
- soar = rise quickly
- demand = need
Question Focus: Scanning for proper nouns
Correct Answer: Ceylon
Passage Reference: 1876. The young trees raised in the tropical greenhouse at Kew were shipped to Ceylon and Ma
Why this is correct: The passage states that rubber trees were shipped to Ceylon. This directly answers the question.
Common Mistake: Students may write Brazil, but that was the original source, not the new supply area. This is a context shift trap.
Paraphrasing: Passage: 'shipped to Ceylon' = Question: 'countries were the new supplies grown'
Tips: For place names, copy the spelling exactly as it appears in the passage.
Key Vocabulary:
- plantation = large farm
- tropical = hot climate
Question Focus: Scanning for proper nouns
Correct Answer: Malaysia
Passage Reference: 1876. The young trees raised in the tropical greenhouse at Kew were shipped to Ceylon and Ma
Why this is correct: Along with Ceylon, the passage names Malaysia as a country where rubber trees were grown. This completes the pair.
Common Mistake: Students may choose another tropical country, but only Malaysia is mentioned. This is a not given trap.
Paraphrasing: Passage: 'Ceylon and Malaysia' = Question: 'which tropical countries'
Tips: When two answers are joined by 'and', they usually come from the same sentence.
Key Vocabulary:
- nucleus = starting group
- supply = amount available
General Tips:
- Summary completion questions follow passage order. Use the previous gap to find the next answer faster.
- Always check the word limit. Even one extra word makes the answer wrong.
- Copy the exact word or words from the passage. Do not use your own synonyms.
- Use grammar clues like articles and prepositions to decide the word form.
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