Part 4 · Natural Rubber Production
Questions 31-36
Complete the flow-chart below.
Write ONE WORD ONLY for each answer.
Natural rubber production
'Tapping' --- tree is cut and a layer of bark is removed
Cup (e.g. made of a 31 shell) is attached to collect latex
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Latex is transferred to the 'factory'
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Latex is poured into a 32
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Formic acid is added to thicken the latex
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Rubber is 33 by hand, to make it into a thin sheet
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Rubber sheet is put through a mangle
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(N.B the only 34 in the process)
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Rubber sheets are taken to be 35 in a special room
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Rubber sheets are purchased by 36
Questions 37-40
Write NO MORE THAN TWO WORDS for each answer.
HISTORY OF RUBBER
Earliest use
• 1525 --- rubber 37 were used in Mexico
19th century
• Key discovery --- 'vulcanisation' made rubber stronger and 38
• Increase in demand when rubber 39 were invented
20th century
• Substitute for natural rubber was first developed in 40 during First World War