The Evolution of Glass IELTS Reading Answers: Vocabulary and Question Strategies

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Each year, millions of candidates take the IELTS (International English Language Testing System) exam. The Reading section is scored on a 9-band scale, with an average Academic Reading band score of 6.26. The test includes 40 questions to be completed in 60 minutes, testing your comprehension and analytical skills.

Test-takers often struggle with inference and complex vocabulary, especially in passages like "The Evolution of Glass." Improving vocabulary and practicing question strategies can increase accuracy and confidence, improving your chances of getting a good score.

This blog explores the Evolution of Glass IELTS Reading Answers, important vocabulary, common mistakes, and scoring strategies to support your IELTS exam preparation.

Decoding the Evolution of Glass IELTS Reading Answers

The IELTS Academic reading passage "Decoding the Evolution of Glass" traces the development of glassmaking from natural obsidian used by early humans to modern high-tech manufacturing.

It highlights milestones, such as the earliest man-made glass, which was used as glazes on beads around 4000 BC, and the advancement to hollow glass containers by 1500 BC. Here is a table summarizing the IELTS test format for IELTS reading answers: "The Evolution of Glass"​:

IELTS Reading Question Type	Skill Assessed
Matching Information or Headings	Linking key ideas to the correct sections or paragraphs.
Multiple Choice	Identifying exact facts, implied meanings, and the most contextually correct option.
Sentence Completion	Locating specific details while preserving the original meaning and grammar.
True / False / Not Given or Yes / No / Not Given	Judging the accuracy of statements based on clearly stated or missing evidence.

Consistent practice with real IELTS Reading section exercises builds accuracy, sharpens strategy, and prepares you to handle various question types confidently.

Also Read: IELTS Exam Fees in India 2025: Complete Breakdown & Cost Guide

Understanding the broader journey of glass helps frame what the passage explores in detail. Let’s now look at how this theme is presented in the actual IELTS reading text for The Evolution of Glass IELTS Reading Answers.

IELTS Reading Passage: The Evolution of Glass IELTS Reading Answers

The passage titled “The Evolution of Glass” (typically 700 words) appears in the IELTS Reading section and focuses on developing, using, and recycling glass materials. It includes technical references and factual descriptions that test comprehension, vocabulary range, and awareness of grammar for IELTS scoring accuracy.

The following are samples of IELTS reading answers: "The Evolution of Glass"​ for your reference:

Passage 1:

Glass has been used since the earliest times. Historians found obsidian, a natural glass formed by volcanic heat, which early humans shaped into spear tips. Around 4000 BC, man-made glass appeared as glazes on stone beads. The first hollow glass container was created by layering molten glass over a sand core.

Passage 2:

From the 1st century BC, glass blowing became the main method for making glass containers. Early glass was often colored due to impurities. By the 1st century AD, techniques to produce colorless glass were developed, and tinted glass was made by adding colorants. Romans spread glass-making across Europe, protecting their methods until their empire’s fall in 476 AD. By the 10th century, Venetian craftsmen gained fame for glass bottles, spreading their skills throughout Europe.

Passage 3:

Englishman George Ravenscroft (1632–1683) made a significant contribution by inventing lead crystal glass. Adding lead during production reduced the cloudiness in blown glass. This glass was softer, easier to decorate, and had greater brilliance. Ravenscroft’s invention was vital to optical instruments such as lenses, telescopes, and microscopes.

Passage 4:

The modern British glass industry grew after the Excise Act was repealed in 1845, ending heavy taxes on glass production. Joseph Paxton’s Crystal Palace at the 1851 London Great Exhibition marked glass’s rise as a key building material. This event increased glass use in public, residential, and horticultural architecture. Advances in science and technology also improved glass manufacturing techniques.

Passage 5:

In 1887, HM Ashley introduced a machine in Castleford, England, that could produce 200 bottles per hour, over three times faster than previous methods. In 1907, Michael Owens, founder of the Owens Bottle Company in the USA, created the first fully automated machine, capable of making 2,500 bottles per hour. Despite rapid progress, glass production shifted during World War I when Britain lost access to key suppliers, and glass began to be viewed as a scientific material rather than just a craft.

Passage 6:

Today, glassmaking is a major industry driven by technology and competition. Modern factories produce millions of glass containers daily, with green and brown the most common colors. Glass plays a crucial role in daily life, from homes and vehicles to packaging for beverages, food, medicines, and cosmetics.

Passage 7:

Glass is ideal for recycling, and growing environmental awareness has increased the popularity of glass bottles and jars. Recycling reduces landfill waste, lowers energy consumption since recycled glass melts more easily than raw materials, and cuts down the need for quarrying, preserving natural resources.

Also read: IELTS Reading Tips For Band 9: Tips And Tricks For IELTS Reading

With the passage fresh in mind, the next step is to see how IELTS questions are formed from it, and how you’re expected to respond based on what’s written.

The Evolution of Glass IELTS Reading Answers: Sample Questions and Answers 

This section focuses on sample questions and answers from the academic IELTS passage about the evolution of glass. It highlights key information and vocabulary essential for accurate responses. The examples demonstrate how to identify specific details and interpret facts effectively.

You can use these samples to enhance your accuracy and time management skills as you prepare for the IELTS.

Sentence Completion (Questions 1-8)

Out of the 13 questions, Sentence Completion makes up over 60% of this IELTS Reading task set. These questions test your ability to locate specific phrases from the passage and complete sentences using words taken directly from the text.

Here are some sentence completion questions related to IELTS reading answers: "The Evolution of Glass"​:

Q1: Early humans used obsidian, a natural glass formed by ______, to make spear tips.

Focus: Identifying the natural formation process of obsidian

Strategy: Look for information about obsidian’s origin in Passage 1

Impact: Tests understanding of specific natural glass formation details

Answer: volcanic heat Explanation: Passage 1 explains that obsidian is a natural glass created by the intense heat of volcanic eruptions melting rock. Early humans shaped this naturally formed glass into tools such as spear tips. This fact connects natural geological processes to early human use of materials, emphasizing the origin of glass before man-made production began.

Q2: The first hollow glass container was made by layering molten glass over a ______ core.

Focus: Understanding the technique used to create early glass containers

Strategy: Search Passage 1 for the description of early glass container production

Impact: Tests ability to extract technical details about ancient glassmaking methods

Answer: sand Explanation: Passage 1 describes how early glassmakers created hollow glass containers by layering molten glass over a sand core. This technique allowed the creation of shapes with empty interiors, marking a significant step in glassmaking history. The sand core provided a mold around which the glass could be formed and later removed.

Q3: Glass blowing, the main method for making glass containers from the 1st century BC, often produced glass that was highly ______ due to impurities.

Focus: Identifying characteristics of early glass blowing products

Strategy: Look for details about early glass color in Passage 2

Impact: Assesses ability to recognize causes of material properties in historical manufacturing

Answer: colored Explanation: According to Passage 2, early glass blowing produced glass that was highly colored because of impurities present in the raw materials. These impurities affected the glass’s clarity, resulting in various colors. This detail is important for understanding how early glass differed from later, clearer versions.

Q4: Techniques to create colorless glass were developed during the ______ century AD.

Focus: Locating the period when colorless glass technology emerged

Strategy: Find timeline references related to colorless glass in Passage 2

Impact: Evaluates the ability to understand historical technological advances

Answer: first Explanation: Passage 2 explains that during the first century AD, methods to make colorless glass were developed, which was a major innovation. Before this, glass was naturally colored due to impurities. This advance allowed for clearer, more versatile glass products, influencing the subsequent use and spread of glassmaking techniques.

Q5: Venetians became well-known for making glass bottles with technical skill and artistic ability from the ______ century.

Focus: Identifying the historical period of Venetian glassmaking fame

Strategy: Search Passage 2 for references to Venetian glassmakers and their era

Impact: Tests knowledge of historical and geographical glassmaking centers

Answer: tenth Explanation: Passage 2 highlights that by the 10th century, Venetian craftsmen had earned a reputation for their skill in glass bottle making. Their expertise combined both technical and artistic qualities, contributing to Venice’s status as a major glassmaking center. This helped spread glassmaking skills across Europe.

Q6: Lead crystal glass, invented by George Ravenscroft, was softer and had greater ______ compared to previous glass types.

Focus: Recognizing the qualities of lead crystal glass

Strategy: Identify the characteristics of Ravenscroft’s glass in Passage 3

Impact: Tests understanding of technological improvements in glass properties

Answer: brilliance Explanation: Passage 3 details that lead crystal glass, invented by Ravenscroft, was softer and easier to decorate, with a higher refractive index that gave it greater brilliance. This made it more attractive and functional, especially for optical uses. These qualities marked a significant improvement in glass manufacturing.

Q7: Joseph Paxton’s Crystal Palace in 1851 marked the beginning of glass being used in ______ architecture.

Focus: Understanding the architectural impact of glass innovation in the 19th century

Strategy: Find references to Crystal Palace and its architectural significance in Passage 4

Impact: Measures comprehension of glass use in building history

Answer: public, domestic, and horticultural Explanation: Passage 4 explains that Joseph Paxton’s Crystal Palace showcased glass as a material for public, domestic, and horticultural buildings. This event was a turning point in architectural history, promoting glass beyond decorative uses to structural applications. It reflects how technology and design converged in glass use.

Q8: Michael Owens’ fully automated glass bottle machine, developed in 1907, could produce ______ bottles per hour.

Focus: Knowing key technological advancements in glass production rates

Strategy: Locate Owens’ invention details in Passage 5

Impact: Tests attention to specific technological data in glass manufacturing history

Answer: 2,500 Explanation: Passage 5 states that Michael Owens developed the first fully automated bottle-making machine capable of producing 2,500 bottles per hour. This was a major leap from earlier methods, which produced far fewer bottles. Owens’ innovation significantly increased production speed and efficiency in the glass industry.

Also Read: Academic IELTS vs General IELTS: Difference Between Academic And General IELTS

Once factual details are tackled, the next layer tests your understanding of opinion and inference through True, False, and Not Given statements.

True / False / Not Given (Questions 9-13)

Questions 9–13 are True / False / Not Given, focusing on whether the passage directly supports, contradicts, or omits the information stated. “True” means the passage clearly confirms the statement; “False” means it contradicts it; “Not Given” indicates the text doesn’t mention it at all.

Careful distinction between what's stated and what's implied is crucial here. Below is a list of 5 True / False / Not Given questions from The Evolution of Glass IELTS Reading Answers.

Q9: The use of glass in modern life is limited mainly to decorative purposes.

Focus: Determining the accuracy of glass usage in daily life

Strategy: Review Passage 6 for the extent of glass applications

Impact: Tests ability to assess the scope of information provided

Answer: False Explanation: Passage 6 highlights that glass is integral to many aspects of modern life, including homes, cars, packaging for beverages, food, medicines, and cosmetics. It is not limited to decoration but plays practical roles across industries. This wide usage contradicts the statement, making it false.

Q10: Recycling glass reduces energy consumption compared to using raw materials.

Focus: Evaluating environmental benefits of glass recycling

Strategy: Look for details on recycling advantages in Passage 7

Impact: Measures comprehension of sustainability concepts related to glass

Answer: True Explanation: Passage 7 confirms that recycling glass requires less energy to melt than raw materials, saving fuel and production costs. This energy efficiency is a key environmental benefit of glass recycling. The passage clearly supports the statement, confirming its truth.

Q11: Glass production stopped during World War I due to lack of suppliers.

Focus: Verifying the continuity of glass production during wartime

Strategy: Find references to glass production in World War I in Passage 5

Impact: Tests understanding of historical production changes

Answer: Not Given Explanation: Passage 5 states Britain was cut off from essential glass suppliers during World War I and that glass production shifted toward scientific uses. However, it does not explicitly say that production stopped altogether. Therefore, the statement is not supported or contradicted, making it Not Given.

Q12: Venetians kept their glassmaking skills secret even after the fall of the Roman Empire.

Focus: Assessing the spread of glassmaking knowledge post-Rome

Strategy: Compare Passage 2 details about Roman and Venetian practices

Impact: Checks recognition of historical information about knowledge sharing

Answer: False Explanation: Passage 2 explains that Romans guarded their glassmaking skills during their empire but after its fall in 476 AD, glassmaking spread across Europe and the Middle East. Venetians later became famous for glass bottles but did not maintain secrecy as tightly as the Romans. This shows the statement is false.

Q13: Glass bottles and jars are becoming more popular due to growing environmental concerns.

Focus: Understanding consumer trends related to glass recycling

Strategy: Locate statements on glass popularity in Passage 7

Impact: Tests ability to connect environmental awareness with market trends

Answer: True Explanation: Passage 7 indicates that glass bottles and jars are increasingly favored because of rising environmental awareness. Recycling benefits and resource conservation encourage consumers to choose glass over other materials. This directly supports the statement as true.

Completing these questions reveals the importance of vocabulary and how it shapes both the questions and your ability to answer them. So, let’s break down some key terms used in this passage.

Vocabulary from The Evolution of Glass IELTS Reading Answers

Understanding historical and technical terms is crucial for achieving a high score, especially if you are aiming for an IELTS Band 7 or Band 8. This passage on glass spans thousands of years, introducing layered vocabulary linked to trade, industry, and science.

From “obsidian” to “automated process,” each term reflects a precise stage in the transformation of glassmaking. Below is a table that breaks down these terms, including their meanings and how they’re used in the passage.

Term	Meaning	Contextual Usage
Obsidian	Naturally occurring volcanic glass	“Early humans shaped obsidian into cutting tools and spear tips.”
Sand core technique	A method where molten glass is shaped around a sand core	“The first hollow containers were made by layering glass over a sand core.”
Glass blowing	Technique of inflating molten glass to form containers	“From the 1st century BC, glass blowing became the standard method of container production.”
Colorless glass	Glass made clear by removing natural impurities	“Colorless glass emerged in the first century AD using purification techniques.”
Venetian glassmaking	Skilled glass production originating in Venice from the 10th century	“Venetian craftsmen were known for decorative and technical excellence in glass.”
Lead crystal	A soft, high-brilliance glass containing lead oxide	“Ravenscroft’s lead crystal was easier to cut and reflected more light.”
Crystal Palace	A 19th-century building made of iron and glass for London’s Great Exhibition	“The Crystal Palace marked a new phase in architectural glass use.”
Automated bottle machine	A fully mechanical device to produce glass bottles at scale	“Owens’ 1907 machine could manufacture 2,500 bottles per hour.”
Domestic glass use	Every day application of glass in homes and packaging	“Glass became central to modern domestic life, from windows to food jars.”

Also Read: Tips to Improve Pronunciation for IELTS

Beyond single terms, IELTS also expects familiarity with recurring word groups and expressions. These collocations offer more insight into usage within the passage.

Collocations and Phrases

This section highlights the exact expressions used to describe the IELTS reading answers: "The Evolution of Glass"​, from handcrafted techniques to mass production and recycling. Many of these phrases, like “manual glassblowing” or “fuel-efficient melting,” show up in IELTS passages covering industrial history or environmental themes.

Knowing how such collocations function contextually makes it easier to interpret complex descriptions. Here is a table that lists these key phrases along with their meanings in context.

Collocation / Phrase	Meaning
Gradual development	Steady progress over long periods, often through experimentation
Manual glassblowing	Traditional, hand-based method of shaping molten glass
Colorless production	Creating glass free of impurities that would otherwise cause tinting
Scientific material	Glass used in scientific instruments rather than decorative items
Fully automated process	Entire manufacturing completed by machines without human operation
Mass bottle production	High-volume manufacturing of glass containers using machines
Recycling initiative	Organized effort to reuse materials to reduce environmental harm
Raw material conservation	Reducing the need to extract or process new natural resources
Fuel-efficient melting	Melting process that uses less energy, especially when using recycled glass
Environmental concern	Public or industrial focus on sustainability and ecological impact

Also read: How to Prepare for IELTS at Home: The Ultimate Study Guide

Understanding vocabulary is helpful, but without a careful strategy, even strong readers make common errors. Let’s go over where mistakes happen and how to prevent them.

The Evolution of Glass IELTS Reading Answers: Common Mistakes to Avoid

Candidates often miss subtle shifts in timeline or invention, especially when glass innovations are spread across centuries. Misreading who invented what or mixing up British and Roman developments often leads to errors, especially in Sentence Completion and True/False/Not Given sections. 

Below are the most frequent mistakes candidates make with this IELTS general reading passage, along with suggestions on how to correct them.

1. Confusing Time Periods and Inventors:

• Many test-takers wrongly attribute inventions like lead crystal glass or glass-blowing techniques to the wrong era or country.
• Example: If the passage says, “Ravenscroft introduced lead during the 1600s,” choosing an answer linking this to Roman glassmakers would be incorrect.
• Tip: Pay close attention to dates and names linked with each invention—especially Ravenscroft, Owens, and the Venetians.

2. Ignoring Paraphrased Production Processes:

• The passage often rephrases methods like “automated bottle-making” or “blown glass,” which causes confusion in Sentence Completion tasks.
• Example: A question might ask about faster methods introduced in 1887, but the passage uses the term “machine-produced 200 bottles per hour,” not “automated.”
• Tip: Match ideas, not just keywords, and understand what each machine or method actually does.

3. Selecting Grammatically Correct but Factually Wrong Words:

• Many students fill in summary blanks with words that fit the grammar but distort the technical or historical accuracy.
• Example: Writing “hand-blown” instead of “automated” for 1907 developments might fit the sentence, but contradicts the text.
• Tip: Reread the full sentence with your chosen word and confirm it reflects the passage’s factual detail.

4. Misjudging Not Given Statements:

• Some True/False/Not Given questions include extra assumptions, especially around environmental impact or recycling benefits.
• Example: If the passage mentions that recycling “reduces quarrying,” assuming it “stops quarrying altogether” would be a misread, making a “True” answer incorrect.
• Tip: Avoid inserting your own logic; base all answers strictly on what is or isn’t stated.

5. Losing Track of Sequence-Based Information:

• IELTS often tests your ability to follow a sequence, especially over a long passage. This passage covers over 6,000 years of development, so it's easy to confuse the order.
• Example: Thinking that Paxton’s Crystal Palace came after Owens’s 1907 machine just because they’re close in the text.
• Tip: Note clear date markers and map innovations mentally or on paper before answering.

6. Spending Too Long on Technical Terms:

• Trying to decode every word like “obsidian” or “tinted glass” wastes time if the question doesn’t depend on it.
• Example: Spending 4 minutes rereading the obsidian section when no questions reference early tools or volcanic glass.
• Tip: Prioritize scanning only when the question clearly refers to a paragraph, don't over-analyze early history unless it’s asked.

Also Read: Is Computer-Based IELTS Easier than Paper: Which Should You Choose

Avoiding mistakes takes more than awareness. It requires targeted practice. Here are reliable resources to help you train with purpose.

IELTS Preparation Resources for The Evolution of Glass IELTS Reading Answers

Details in The Evolution of Glass IELTS Reading Answers, like glass production speeds, invention years, and material types, often confuse test-takers in this passage. Without the right tools, it's easy to complicate similar phrases or miss subtle factual shifts.

The resources below are selected to sharpen attention to such specifics. Each will help improve reading skills for high-accuracy answers.

Resource	Focus Area	Why Use It?
Free IELTS Exam Preparation Material	Comprehensive IELTS skills	Improves accuracy in sentence completion tied to glassmaking facts.
IELTS Reading Test	Academic Reading Practice	Builds confidence with passages on materials, production, and history.
IELTS Online Coaching	Structured Preparation	Reduces mistakes in timelines and invention-based questions.
IELTS Preparation Videos	Strategy-Based Video Lessons	Simplifies True/False/Not Given using examples similar to Owens, Ravenscroft, and recycling.

Also Read: How to Get IELTS Certificate: A Complete Guide for International Students

If you’re looking for structured support, upGrad’s expert-led approach gives you the tools and feedback needed to build long-term reading confidence.

How Can upGrad Help You Master IELTS Reading Skills?

upGrad’s IELTS Reading training closely mirrors the format and challenges of the actual exam, offering targeted practice for passages like “The Evolution of Glass.” Expert-led video sessions break down complex question types and teach strategies for managing time and identifying key information quickly.

Personalized feedback highlights specific errors and guides you on how to avoid them in future tests. Schedule a free one-on-one session with upGrad experts today and receive customized advice focused on improving your reading strategy.