Flawed Beauty: the problem with toughened glass: reading answers and analysis
Toughened glass is strong and breaks into small cubes, but tiny nickel sulphide crystals can make it shatter without warning years later. The passage explains how toughening traps unstable crystals that expand. Experts disagree on how common failures are, and one Brisbane building needed every pane checked.
The people matching (14-17) takes the experts in the order they appear. The summary (18-23) follows the passage from the benefits of the glass, through manufacture, to the crystals and the disagreement. The TRUE / FALSE / NOT GIVEN block (24-26) uses the first paragraph, the uses paragraph and the data paragraph.
Answer key and self-check
Type what you wrote and hit mark. Hide the key first if you haven't done the passage yet. Every question number jumps to its explanation.
How to attack this block: Several experts are named close together, so read who says what. Two statements belong to people who aren't in the question (Josie sees cases monthly). Each person here has one clear idea: rare, hidden, oldest case, every pane checked.
Question 14
Answer: GParagraph 2
Which statement matches Brian Waldron?
But he insists that cases are few and far between. 'It's a very rare phenomenon,' he says.
Question says → Passage says
claimshe insists
very unusuala very rare phenomenon / few and far between
Why: G. Waldron says nickel sulphide failure is 'very rare' and cases are 'few and far between'. 'Very unusual' is the same claim.
The trap: A could seem to fit, since he works for the glass industry. But Waldron never mentions publicity; it's Trevor Ford who talks about bad press.
Question 15
Answer: AParagraph 3, last two sentences
Which statement matches Trevor Ford?
'What you hear is only the tip of the iceberg,' says Trevor Ford… He believes the reason is simple: 'No-one wants bad press.'
Question says → Passage says
publicity… has been suppressedNo-one wants bad press / only the tip of the iceberg
Why: A. 'Tip of the iceberg' means most cases are hidden, and 'no-one wants bad press' is the reason: news of failures is kept quiet.
The trap: B, regularly sees cases, belongs to Barrie Josie in the same paragraph ('one or two buildings a month'). Ford talks about what's hidden, not how often he sees cases.
Question 16
Answer: HParagraph 8, last two sentences
Which statement matches Graham Dodd?
the oldest pane of toughened glass known to have failed due to nickel sulphide inclusions was in Pilkington's glass research building in Lathom, Lancashire. The pane was 27 years old.
Question says → Passage says
the most extreme case of delayed failurethe oldest pane of toughened glass known to have failed
Why: H. The paragraph explains that failure can come months or decades after manufacture, and Dodd names the oldest known case, a 27-year-old pane. That's the most extreme delay.
The trap: D, involved with Bishops Walk, may come to mind because Pilkington made the Bishops Walk pane. Dodd's example is a different building, and he works for Arup, not Pilkington.
Question 17
Answer: CParagraph 10
Which statement matches John Barry?
John Barry, an expert in nickel sulphide contamination at the University of Queensland, analysed every glass pane in the building.
Question says → Passage says
closely examined all the glass in one buildinganalysed every glass pane in the building
Why: C. Barry analysed every pane in Waterfront Place, using photos scanned for crystals. That's a close examination of all the glass.
The trap: E, recommending the rebuilding of Waterfront Place, is the opposite: re-cladding was the more expensive alternative his project avoided.
Summary completion (word list A-P)
Questions 18-23
How to attack this block: The list has pairs of opposites (quickly and slowly, expands and contracts, warm and cold, agreed and disputed), so read the passage carefully to choose the right side. Check grammar too: adverb, verb or adjective.
Question 18
Answer: FParagraph 4, third sentence
How are the broken fragments of toughened glass different?
when it does break it shatters into tiny cubes rather than large, razor-sharp shards
Question says → Passage says
fragments are not as ___tiny cubes rather than large, razor-sharp shards
Why: F, sharp. Toughened glass breaks into tiny cubes instead of razor-sharp shards, so the pieces are not as sharp.
The trap: O, small, is the near miss: the cubes are tiny. But 'not as small' would mean the pieces are bigger, which is the reverse.
Question 19
Answer: IParagraph 1 and Paragraph 7
How can toughened glass shatter?
shattered without warning and fell from its frame… ready to revert to the beta phase without warning
Question says → Passage says
can shatter ___shattered without warning
Why: I, unexpectedly. 'Without warning' appears twice: the Bishops Walk pane shattered without warning, and the crystals change back without warning.
The trap: C, quickly, sounds possible for shattering, but the passage stresses the lack of warning, and 'quickly' is needed for the cooling gap.
Question 20
Answer: CParagraph 5, first sentence
How is the glass cooled after heating?
and then cooling it rapidly with jets of cold air
Question says → Passage says
cooled very ___cooling it rapidly
Why: C, quickly. 'Rapidly' is the passage's word. The gap needs an adverb after 'cooled very'.
The trap: M, cold, appears right there ('cold air'), but 'cooled very cold' isn't grammatical, and H, slowly, is the opposite.
Question 21
Answer: KParagraph 5, second sentence
What does the outer layer do before the inner layer?
This causes the outer layer of the pane to contract and solidify before the interior.
Question says → Passage says
The outer layer ___ before the inner layerthe outer layer of the pane to contract and solidify before the interior
Why: K, contracts. The outer layer contracts and solidifies first. The gap needs a present-tense verb to go with 'the outer layer'.
The trap: G, expands, is what the crystals do later (and what the structure does during heating). For the cooling stage, the outer layer contracts.
Question 22
Answer: EParagraph 8, third sentence
In what weather are the crystals most likely to expand?
although if the glass is heated - by sunlight, for example - the process is speeded up
Question says → Passage says
particularly if the weather is ___if the glass is heated - by sunlight
Why: E, warm. Heat from sunlight speeds up the change. The Bishops Walk failure also happened on 'a particularly hot day'.
The trap: M, cold, is the trap if you mix up the cooling during manufacture with the conditions that trigger failure later.
Question 23
Answer: LParagraph 2 and Paragraph 3
Do glass experts agree on how often these failures happen?
'It's a very rare phenomenon,' he says. Others disagree.
Question says → Passage says
The frequencycases are few and far between / about one or two buildings a month
___ by glass expertsOthers disagree
Why: L, disputed. Waldron says failures are very rare; Josie, Wilmott, Armstrong and Ford say they see many. When experts disagree, the frequency is disputed.
The trap: D, agreed, is the reverse. P, calculated, fails because paragraph 9 says data on the scale is almost impossible to find.
TRUE / FALSE / NOT GIVEN
Questions 24-26
How to attack this block: One TRUE hinges on 'almost certainly', and one FALSE on data being 'almost impossible to find'. The NOT GIVEN compares appearance, which the passage never does.
Question 24
Answer: TRUEParagraph 1, second sentence
Were experts fairly sure what caused the Bishops Walk pane to break?
they found that minute crystals of nickel sulphide trapped inside the glass had almost certainly caused the failure
Question says → Passage says
Little doubtalmost certainly
Why: TRUE. 'Almost certainly' means there was very little doubt about the cause.
The trap: Paragraph 3 starts 'Others disagree', which some people apply to this. That disagreement is about how common the problem is, not about the cause at Bishops Walk.
Question 25
Answer: NOT GIVENParagraph 4
Does toughened glass look the same as ordinary glass?
This glass has five times the strength of standard glass
Question says → Passage says
ordinary glassstandard glass
Why: NOT GIVEN. The passage compares strength and how the glass breaks, but never says whether the two look alike.
The trap: Architects use it for 'transparent walls', which might make you assume it looks like normal glass. Appearance compared with ordinary glass isn't stated.
Question 26
Answer: FALSEParagraph 9, first sentence
Is there lots of recorded evidence on how often nickel sulphide failure occurs?
Data showing the scale of the nickel sulphide problem is almost impossible to find.
Question says → Passage says
plenty of documented evidenceData… is almost impossible to find
the incidencethe scale of the nickel sulphide problem
Why: FALSE. Data is 'almost impossible to find', the opposite of plenty of evidence.
The trap: The experts in paragraph 3 report hundreds of cases, which might suggest lots of evidence. Those are personal experiences, and the writer says documented data is scarce.
TRUE. 'Almost certainly caused the failure' shows little doubt. The later disagreement is about how often failures happen.
Words from this passage worth keeping
minute(Paragraph 1)
extremely small
few and far between(Paragraph 2)
rare; not happening often
tip of the iceberg(Paragraph 3)
a small visible part of a much bigger problem
propagate(Paragraph 5)
spread or travel through something
impurities(Paragraph 6)
unwanted substances mixed into a material
primed(Paragraph 7)
ready to act at any moment
elapses(Paragraph 8)
passes (of time)
inclusion(Paragraph 9)
a small foreign particle trapped inside a material
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The full Cambridge 5 Test 4 reading paper: all three passages, 60 minutes, marked the second you finish with a review of every answer. Already done it? Take it again and see if the same traps still get you.
Cambridge IELTS 5, Test 4, Reading Passage 2. The passage and questions belong to Cambridge University Press and are not reproduced here. We quote short extracts only as evidence for our own commentary, and the answers are published for self-marking. Get the book for the full text, or sit the test on Langujet.
