Real Reading Test Pre 2025 - Vol 1 Test 1 with Practice Test, Answers And Explanation
Luyện tập đề Real Reading Test Pre 2025 - Vol 1 Test 1 được lấy từ cuốn sách Real Test Pre 2025 - Vol 1 với trải nghiệm thi IELTS trên máy và giải thích đáp án chi tiết bằng Linearthinking, kèm answer key và list từ vựng IELTS cần học trong bài đọc.
Real Reading Test Pre 2025 - Vol 1 Test 1 with Practice Test, Answers And Explanation
Passage
❓ Câu hỏi passage 1
Question 1 - 8
Complete the table below.
Choose NO MORE THAN TWO WORDS from the passage for each answer.
Location and year
Occurence
Resulting change to food supply
Impact on next generation of medium ground finches
Daphne Major,1977
Drought
Shortage of
1
More birds with
2
Daphne Major,
1985
Dense vegetation caused by unusually
3
Lack of plants producing
4
Domination of birds with
5
Daphne Major,2002 - 2003
6
Competition for food from immigrant finch species
Higher proportion of birds with smaller bills
Santa Cruz, late 1960s onwards
Rapid expansion of the human population
Introduction of new foods, eg
7
at bird feeding stations
Increase in number of birds with
8
Question 9 - 13
Choose
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if it is impossible to say what the writer thinks about this
9
The Grants' observations brought Darwin's ideas into question.
10
The Galápagos cactus finch is less affected by variations in food supply than the medium ground finch.
11
All types of ground finches on Daphne Major were affected by the adverse weather conditions in 2002 and 2003.
12
Hendry and Podos observed the same changes in finch population throughout the island of Santa Cruz.
13
There is evidence to suggest that the course of species diversification on Santa Cruz has been altered.
Passage
❓ Câu hỏi passage 2
Question 14 - 20
Choose
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if it is impossible to say what the writer thinks about this
14
The majority of ancient Greeks followed the advice of Hippocrates about cold foods.
15
Seneca had different reactions to Nero's various uses of snow.
16
Many ancient Romans went to the mountains in the summer to eat ice cream.
17
The cold storage houses in Rome were generally built of frozen blocks of ice.
18
The buying and selling of snow and ice became a common international activity during Roman times.
19
Tang Dynasty Chinese preferred chilled desserts made from milk to those made only of snow and ice.
20
The freezing temperature of most types of milk made it easy to create frozen dairy desserts.
Question 21 - 27
Complete the notes below.
Choose ONE WORD ONLY from the passage for each answer.
The development of modern ice cream
Early publications about making ice cream
- 1530: First known written references to ice cream.
- 18th century:
First book in English with for ice cream was published in 1718.
Many different ingredients were added to ice cream desserts.
Notable consumers of ice cream
- It was once widely thought that ice cream was mostly eaten by the .
- Ice cream desserts were:
created for French King Louis XV's court.
served at an important for an American president.
18th-century Naples, Italy
- Lower-class people also enjoyed ice cream.
- of ice cream could be seen on the streets.
Improvements in ice cream production
- Before 1843, ice cream was not stirred while being frozen so it had an unpleasant .
- Nancy Johnson invented a freezer which included a to turn a cylinder.
- 20th-century production methods allowed a reduction in the of commercially sold ice cream.
Passage
❓ Câu hỏi passage 3
Question 28 - 33
Complete each sentence with the correct ending A-H.
List of Findings
A
was developed as a substitute for a natural fibre.
B
became very popular when a product made of it was launched.
C
was too expensive to manufacture.
D
combined animal and synthetic products.
E
was initially intended to protect cloth.
F
was regarded with suspicion by the general public.
G
broke when first used for its intended purpose.
H
was the first plastic that permanently retained its shape after being moulded.
28
Parkesine
29
Celluloid
30
Rayon
31
Bakelite
32
Cellophane
33
Nylon
Question 34 - 40
Choose NO MORE THAN ONE WORD for each answer.
Polyethylene
In 1933, two organic chemists applied extreme to ethylene and benzaldehyde, to discover what would occur. The experiment was spoiled by a minor during the test process, but the scientists found that polyethylene had been created. A was built to manufacture polyethylene on a large scale. The material was later used as a for submarine cables and to provide in radar systems, allowing them to be carried on
DOL IELTS Đình Lực
05/05/2026
📖 Bài đọc passage 1
The continuing saga of the Galápagos Finches
Galápagos finches, the island birds that helped shape Charles Darwin's theory of evolution, are giving scientists new insights into how natural selection works
In 1835, naturalist Charles Darwin arrived on the Galápagos islands off the Pacific coast of South America. Observation of the islands' many different species of finches inspired his revolutionary theory of evolution, and set him on the quest that would consume him for the rest of his life: the struggle to understand how new species come into being.
Today, that quest continues. On Daphne Major - one of the most desolate of the Galápagos Islands - biologists Peter and Rosemary Grant have spent more than three decades watching Darwin's finches respond to the challenges of storms, drought and competition for food. They know and recognise many of the individual birds on the island and can trace the birds' lineages back through time. They have witnessed Darwin's principle in action again and again, over many generations of finches.
The Grants' most dramatic insights have come from watching the evolving bill (hard mouth part) of the medium ground finch (geospiza fortis). Its bill is a middling example in the array of shapes and sizes found among Galápagos finches: larger than that of the small ground finch (geospiza fuliginosa), which specialises in eating small, soft seeds, but not as big as that of the large ground finch (geospiza magnirostris), an expert at cracking and devouring big, hard seeds.
When the Grants began their study in the 1970s, only two species of finch lived on Daphne Major - the medium ground finch and the cactus finch (geospiza scandens). When a severe drought hit in 1977, the last of the small seeds were soon devoured, and the members of the medium ground finch population who lacked the bill strength to crack large seeds soon died out. Bill and body size are inherited traits, and the next generation of medium ground finches had a high proportion of individuals with large bills. The Grants had documented natural selection at work.
Eight years later, in 1985, heavy rain transformed the normally meagre vegetation on Daphne Major. Vines and other plants that in most years struggle for survival suddenly flourished, choking out the plants that provide large seeds for the finches. Small seeds came to dominate the food supply, and medium ground finches with small bills dominated the next generation to be born.
More recently, the Grants witnessed another form of natural selection acting on the medium ground finch: competition from bigger, stronger cousins. In 1982, the large ground finch (geospiza magnirostris) came to live on Daphne Major. Over the next 20 years the two species coexisted, with the medium ground finch sharing its supply of large seeds with the bigger-billed newcomer. Then, in 2002 and 2003, there was another drought. None of the birds nested that year, and many died out.
Medium ground finches with large bills, crowded out of feeding areas by the more powerful large ground finches, were hit particularly hard. When wetter weather returned in 2004, and the finches nested again, the new generation of medium ground finches was again dominated by birds with smaller bills, able to survive on smaller seeds. This situation, says Peter Grant, marked the first time that biologists have been able to follow the complete process of an evolutionary change due to competition between species.
On the island of Santa Cruz, just south of Daphne Major, Andrew Hendry of McGill University and Jeffrey Podos of the University of Massachusetts at Amherst have discovered a new, man-made twist in finch evolution. Their study focused on birds living near the Academy Bay research station, on the fringe of the town of Puerto Ayora. The human population of the area had been growing fast since the late 1960s.
Academy Bay finch records dating back to the early 1960s show that medium ground finches captured there had either small or large bills. Very few of the birds had medium bills. The finches appeared to be in the early stages of a new adaptive radiation: if the trend had continued, the medium ground finch on Santa Cruz could have split into two distinct subspecies specialising in different types of seeds. But in the late 1960s and early 70s, medium ground finches with medium bills began to thrive along with small- and large-billed birds. The townspeople had introduced new food sources, such as rice, which they put in bird feeding stations. Bill size, once critical to the finches' survival, no longer made any difference.
At a control site on Santa Cruz, distant from Puerto Ayora, and relatively untouched by humans, Hendry and Podos noted that the medium ground finch population remained split between large- and small-billed birds. On such undisturbed parts of the island there is no ecological niche for a medium-billed bird, and the birds continue to diversify. In town, however, once-distinct populations of finches are merging.
The finches of Santa Cruz demonstrate a subtle process in which human meddling can halt evolution in its tracks, ending the formation of new species. In a time when global biodiversity continues its downhill slide, Darwin's finches have yet another unexpected lesson to teach. 'If we hope to regain some of the diversity that's already been lost,' Hendry says, 'we need to protect not just existing creatures, but also the processes that drive the origin of new species.'
🔥 Đáp án & giải thích 1
1
Small seeds / small seeds
Giải thích chi tiết
☺️ Ứng dụng Linearthinking để giải quyết dạng bài Gap Fill
Step 01: Read the question to understand (main idea + detail) + Predict Word Form + Meaning
Simplified: In Daphne Major, 1977 , a drought led to the shortage of ______
Main idea: Trên đảo Daphne Major vào năm 1977, hạn hán đã gây ra tình trạng khan hiếm một loại thức ăn cụ thể của loài chim sẻ.
Prediction: Danh từ (N, plural) → chỉ nguồn thức ăn mà chim thường ăn (ví dụ: seeds, insects, plants...).
-------
Step 02: Locate relevant information
🔍 Từ khoá: “Daphne Major”, “1977”, “drought”, “shortage”
→ Dựa vào các từ khoá ở trên có thể xác định được đoạn cần đọc là đoạn 4.
-------
Step 03: Read relevant information to understand (main + detail)
📌Trích dẫn: "Only two species of finch lived on Daphne Major - the medium ground finch and the cactus finch (Geospiza scandens). When a severe drought hit in 1977, the last of the small seeds were soon devoured..."
Simplified: When a drought hit in 1977 , the small seeds were devoured .
Main idea: Năm 1977, hạn hán khiến toàn bộ hạt nhỏ bị ăn hết → dẫn đến tình trạng khan hiếm thức ăn cho chim sẻ.
-------
Step 04: Compare meaning with meaning
Trong bài đọc: “the last of the small seeds were soon devoured” → các hạt nhỏ bị ăn hết sau đợt hạn hán.
Trong câu hỏi: “a drought led to the shortage of ______” → hỏi thiếu hụt gì sau hạn hán.
→ Từ cần điền là "hạt nhỏ".
People the world over love ice cream. But they seldom consider how the frozen dessert came into being. Ice cold desserts, called 'ices', were around as far back as the 5th century BC, when the ancient Greeks refreshed themselves with snow, flavoured with honey or fruits. Although the Greek physician Hippocrates warned his patients to avoid unhealthy chilled drinks, these icy treats nonetheless enjoyed tremendous popularity. The ancient Romans were also familiar with ices. While the philosopher Seneca criticised the emperor Nero in the 1st century AD for the extravagance of having ice and snow brought from the mountains to cool his swimming pool, he seemed to have seen nothing wrong with the emperor's fondness for chilled drinks and snow flavoured with honey.
But at that time, unless Romans wanted to eat their ices only in winter or high in the mountains, they needed not only to bring snow or ice to where they consumed it, but also to find some way of storing it in warm weather. This required a special sort of building now known as an ice house. Usually constructed of stone, underground and insulated with straw, these were sufficiently cold to preserve ice cut from frozen lakes and rivers in winter, or snow carried down from the mountains. Ice houses were in regular use in ancient Rome, and their growing use soon led to the development of a busy trade in snow and ice crisscrossing Europe, the Mediterranean and parts of western Asia.
Yet desserts made with cold dairy products were not invented until much later. During the Tang Dynasty (AD 616-907), the Chinese made a cold, creamy concoction of buffalo milk, flour, camphor and snow. But while it was easy enough to cool milk down, this mixture proved difficult to freeze. This was simply a matter of physics. Most milk freezes at between
\ -0.535 degrees C and -0.565 degrees C, which is below the freezing point of water; so packing it in frozen water or snow doesn't get milk cold enough to become solid. Surprisingly, the solution to this problem was salt. When salt is added to snow or ice, energy is absorbed from a container of milk, for example, set within the snow or ice, reducing the milk's temperature and creating a basic form of refrigeration of freezing.
No one knows precisely when a mixture of salt and snow or ice was first used to produce ice cream. The earliest recorded references to what we know as ice cream occurred in Europe around 1530. However, it was not until the publication of a cookbook by Mrs Mary Eales in 1718 that recipes showing how to make it appeared in English. At that time, there was considerable variation in the ingredients. Milk, cream and custard were used almost interchangeably; and books of the period recommended including, for example, rose petals, caramel, ginger, lemon, chocolate, parsley and even asparagus.
For many years, historians assumed that it was the aristocracy that were the main consumers of these early ice creams. During the 18th century, for example, a range of beautiful ice cream dishes were created for French King Louis XV and his court. In 1813, US President James Madison's wife arranged for ice creams to be given to guests at her husband's inaugural ball; two years later, the French writer Balzac described the lavish ice cream desserts consumed in the great houses of Paris in his novel Splendeurs et misères des courtisanes. But, especially in 18th-century Naples in Italy, in part because of the relatively easy access to snow, it was also possible for people much lower down the social scale to make, sell and enjoy ice cream. Not only were there shops and cafés selling ice creams, but there were also vendors who sold it along the public roads, and there is evidence to suggest that some families may have made it at home.
However, early ice creams were still quite different from the iced treats we enjoy today. Since the milk, cream or custard was not stirred as it was frozen, it formed icy chunks, resulting in a lumpy, disagreeable texture. In 1843, however, an American called Nancy Johnson designed a hand-turned freezer, which allowed her to make silky smooth ice cream. Her invention consisted of a large container filled with ice and salt, a tightly closed cylinder for the milk or cream and a removable handle, which was rotated to stir the ice cream until properly frozen.
Even with Nancy Johnson's freezer, however, it was only possible to make small batches of ice cream at a time. But in 1926 another American, Clarence Vogt, improved on Johnson's idea with his continuous freezer, which made it possible to produce ice cream on an industrial scale. The inventions of Johnson and Vogt resulted in an explosion in the output of ice cream, which pushed the price down, making ice cream available to everyone everywhere. As more companies started manufacturing their own brands, increased competition led to the standardisation of the commercial product and to more inventive varieties.
🔥 Đáp án & giải thích 2
14
False
Giải thích chi tiết
☺️ Ứng dụng Linearthinking để giải quyết dạng bài True / False / Not Given
Step 01: Read the question to understand (main idea + detail)
Simplified: The majority of ancient Greeks followedthe adviceof Hippocrates about cold foods
Main idea: Phần lớn người Hy Lạp cổ đại - nghe theo lời khuyên của Hippocrates - về việc không ăn/uống đồ lạnh → tuân theo lời khuyên của ông.
-------
Step 02: Locate relevant information
🔍 Từ khóa: "The majority", “Hippocrates”, “ancient Greeks”, “cold foods”
→ Dựa vào các từ khoá trên → Tìm được trích dẫn ở đoạn 1
-------
Step 03: Read relevant information to understand (main + detail)
📌 Trích dẫn: “Although the Greek physician Hippocrates warned his patients to avoid unhealthy chilled drinks, these icy treats nonetheless enjoyed tremendous popularity.” (Đoạn 1)
Simplified: Although Hippocrates warned patients to avoid unhealthy chilled drinks><these icy treatsenjoyedtremendous popularity
Main idea: Hippocrates khuyên bệnh nhân tránh đồ uống lạnh - nhưng món tráng miệng lạnh vẫn rất phổ biến→ người Hy Lạp KHÔNG làm theo lời khuyên của ông.
-------
Step 04: Compare meaning with meaning
Trong bài đọc: Hippocrates khuyên tránh đồ uống lạnh, nhưng người Hy Lạp vẫn thích và tiêu thụ nhiều → họ KHÔNG làm theo lời khuyên.
Trong câu hỏi: Người Hy Lạp phần lớn nghe theo lời khuyên của Hippocrates về đồ lạnh.
⇒ ✅ Chọn: FALSE
-------
Lưu ý chung:
Nếu đáp án là TRUE: Câu trong bài phải nói rằng hầu hết người Hy Lạp nghe theo lời khuyên của Hippocrates và tránh đồ lạnh.
Nếu đáp án là NOT GIVEN: Câu trong bài không nói gì về việc người Hy Lạp có tuân theo lời khuyên đó hay không.
Plastics affect of our lives - from packaging to cutting-edge technologies in cars and computers, from new textiles to replacements for worn-out parts of our bodies. But none of the applications and innovations we take for granted would have been possible if it weren't for the early scientists who developed and refined the material.
The first man-made plastic, Parkesine, was unveiled in London in 1862. This was an organic material derived from cellulose that once heated could be moulded, and on cooling retained its shape until it was reheated. But because of the high cost of raw materials, production soon came to an end.
During the 19th century, the game of billiards became so popular that thousands of elephants were killed for their ivory-used to make billiard balls. A replacement, celluloid, was found by an American, Hyatt, in 1866. On spilling a bottle of collodion, he discovered that the material congealed into a tough, flexible film. He then used it to produce billiard balls, but they shattered once they hit each other, a problem subsequently solved by the addition of camphor. Celluloid was the first thermoplastic: a substance that can be moulded under heat and pressure. Celluloid was later used in the first flexible photographic film for still and motion pictures.
Rayon, another modified cellulose, was first developed in 1891 by Frenchman Bernigaut, while searching for a way to produce man-made silk. Bernigaut noticed that silkworms secrete a liquid that hardens upon exposure to air and turns into silk. He produced a liquid with similar characteristics, which could the be processed to form fibres that could be spun and would feel like silk. The only problem with his new invention was that it was highly flammable. This problem was later solved by another scientist.
The first completely synthetic man-made substance was discovered in 1907, when Baekeland, a New York chemist, developed a liquid resin that he named Bakelite. All previous plastics could be melted down innumerable times and reformed. Bakelite, however, had the advantage that once shaped, it would never melt or burn. It could also be added to almost any material - such as softwood - and would instantly make it more durable and effective. This new material began to be used for a wide range of products.
Cellophane was discovered by Brandenberger, a Swiss textile engineer. He wanted to apply a clear flexible film to fabrics, such as tablecloths, so that they could be cleaned easily. In 1913 he succeeded by using Viscose (now known as Rayon), but this made the material too stiff to be of any use. Brandenberger saw another potential use, though. He produced sheets of it, which he marketed as Cellophane. This could be used as a clear layer of packaging for any product - the first fully flexible, waterproof wrap.
The 1920s witnessed a 'plastics craze', as the use of cellophane spread throughout the world. Nylon, initially discovered in Germany, was developed in the USA. Its toughness made it a suitable replacement for animal hair in toothbrushes, and when nylon stockings were launched in 1939, they gained great public acceptance.
In 1933 Fawcett and Gibson, two British organic chemists working for the company ICI, discovered polyethylene while testing various chemicals. An attempt to trigger a reaction between ethylene and benzaldehyde under high pressure went wrong when the testing seemed to spring a leak. Upon opening the tube the scientists found a waxy, plastic-like substance, polyethylene. After further experimentation and analysis, they discovered that while the process did have a small leak, the main cause of pressure loss was a polymerization process that combined elements. In 1936, ICI developed a compressor that made possible the production of vast quantities of polyethylene.
Polyethylene played a key role during World War II in the 1940s - first as an underwater cable coating and then as insulation for radar. As polyethylene was very much lighter that the materials traditionally used for the latter purpose, it was now possible for the first time to place radar on planes. This helped in the detection of enemy bombers at night.
After the war the material became very popular with consumers, and it is currently the largest volume plastic in the world, used to make a wide range of common items, such as plastic food storage containers.
🔥 Đáp án & giải thích 3
28
C
Giải thích chi tiết
☺️ Ứng dụng Linearthinking để giải quyết dạng bài Matching Names
Step 01: Read the question to understand main idea
Question: Parkesine
Main idea: Parkesine có tính chất/đặc điểm gì?
-------
Step 02: Locate relevant information
🔍 Từ khoá đặc biệt: Parkesine → Dựa vào từ khoá có thể xác định được đoạn cần đọc là đoạn 2.
-------
Step 03: Read relevant information to understand (main + detail)
📌 Trích dẫn:"The first man-made plastic, Parkesine, was unveiled in London in 1862. But because of the high cost of raw materials, production soon came to an end."
Simplified: Parkesine - because of high cost -> production came to an end
Main idea:Parkesine ra đời sớm nhưng việc sản xuất phải dừng lại do chi phí nguyên liệu quá cao.
-------
Step 04: Compare meaning with meaning
Nội dung tìm được trong bài: Việc sản xuất Parkesine bị dừng lại vì chi phí nguyên liệu cao.
Nội dung câu hỏi: Parkesine có tính chất/đặc điểm gì?
✅ Thông tin này khớp với: C. was too expensive to manufacture.
In 1835, naturalist Charles Darwin arrived on the Galápagos islands off the Pacific coast of South America. Observation of the islands' many different species of finches inspired his revolutionary theory of evolution, and set him on the quest that would consume him for the rest of his life: the struggle to understand how new species come into being.
Today, that quest continues. On Daphne Major - one of the most desolate of the Galápagos Islands - biologists Peter and Rosemary Grant have spent more than three decades watching Darwin's finches respond to the challenges of storms, drought and competition for food. They know and recognise many of the individual birds on the island and can trace the birds' lineages back through time. They have witnessed Darwin's principle in action again and again, over many generations of finches.
The Grants' most dramatic insights have come from watching the evolving bill (hard mouth part) of the medium ground finch (geospiza fortis). Its bill is a middling example in the array of shapes and sizes found among Galápagos finches: larger than that of the small ground finch (geospiza fuliginosa), which specialises in eating small, soft seeds, but not as big as that of the large ground finch (geospiza magnirostris), an expert at cracking and devouring big, hard seeds.
When the Grants began their study in the 1970s, only two species of finch lived on Daphne Major - the medium ground finch and the cactus finch (geospiza scandens). When a severe drought hit in 1977, the last of the small seeds were soon devoured, and the members of the medium ground finch population who lacked the bill strength to crack large seeds soon died out. Bill and body size are inherited traits, and the next generation of medium ground finches had a high proportion of individuals with large bills. The Grants had documented natural selection at work.
Eight years later, in 1985, heavy rain transformed the normally meagre vegetation on Daphne Major. Vines and other plants that in most years struggle for survival suddenly flourished, choking out the plants that provide large seeds for the finches. Small seeds came to dominate the food supply, and medium ground finches with small bills dominated the next generation to be born.
More recently, the Grants witnessed another form of natural selection acting on the medium ground finch: competition from bigger, stronger cousins. In 1982, the large ground finch (geospiza magnirostris) came to live on Daphne Major. Over the next 20 years the two species coexisted, with the medium ground finch sharing its supply of large seeds with the bigger-billed newcomer. Then, in 2002 and 2003, there was another drought. None of the birds nested that year, and many died out.
Medium ground finches with large bills, crowded out of feeding areas by the more powerful large ground finches, were hit particularly hard. When wetter weather returned in 2004, and the finches nested again, the new generation of medium ground finches was again dominated by birds with smaller bills, able to survive on smaller seeds. This situation, says Peter Grant, marked the first time that biologists have been able to follow the complete process of an evolutionary change due to competition between species.
On the island of Santa Cruz, just south of Daphne Major, Andrew Hendry of McGill University and Jeffrey Podos of the University of Massachusetts at Amherst have discovered a new, man-made twist in finch evolution. Their study focused on birds living near the Academy Bay research station, on the fringe of the town of Puerto Ayora. The human population of the area had been growing fast since the late 1960s.
Academy Bay finch records dating back to the early 1960s show that medium ground finches captured there had either small or large bills. Very few of the birds had medium bills. The finches appeared to be in the early stages of a new adaptive radiation: if the trend had continued, the medium ground finch on Santa Cruz could have split into two distinct subspecies specialising in different types of seeds. But in the late 1960s and early 70s, medium ground finches with medium bills began to thrive along with small- and large-billed birds. The townspeople had introduced new food sources, such as rice, which they put in bird feeding stations. Bill size, once critical to the finches' survival, no longer made any difference.
At a control site on Santa Cruz, distant from Puerto Ayora, and relatively untouched by humans, Hendry and Podos noted that the medium ground finch population remained split between large- and small-billed birds. On such undisturbed parts of the island there is no ecological niche for a medium-billed bird, and the birds continue to diversify. In town, however, once-distinct populations of finches are merging.
The finches of Santa Cruz demonstrate a subtle process in which human meddling can halt evolution in its tracks, ending the formation of new species. In a time when global biodiversity continues its downhill slide, Darwin's finches have yet another unexpected lesson to teach. 'If we hope to regain some of the diversity that's already been lost,' Hendry says, 'we need to protect not just existing creatures, but also the processes that drive the origin of new species.'
a drought
hit in 1977
the small seeds
were devoured
Main idea: Năm 1977, hạn hán khiến toàn bộ hạt nhỏ bị ăn hết → dẫn đến tình trạng khan hiếm thức ăn cho chim sẻ.
People the world over love ice cream. But they seldom consider how the frozen dessert came into being. Ice cold desserts, called 'ices', were around as far back as the 5th century BC, when the ancient Greeks refreshed themselves with snow, flavoured with honey or fruits. Although the Greek physician Hippocrates warned his patients to avoid unhealthy chilled drinks, these icy treats nonetheless enjoyed tremendous popularity. The ancient Romans were also familiar with ices. While the philosopher Seneca criticised the emperor Nero in the 1st century AD for the extravagance of having ice and snow brought from the mountains to cool his swimming pool, he seemed to have seen nothing wrong with the emperor's fondness for chilled drinks and snow flavoured with honey.
But at that time, unless Romans wanted to eat their ices only in winter or high in the mountains, they needed not only to bring snow or ice to where they consumed it, but also to find some way of storing it in warm weather. This required a special sort of building now known as an ice house. Usually constructed of stone, underground and insulated with straw, these were sufficiently cold to preserve ice cut from frozen lakes and rivers in winter, or snow carried down from the mountains. Ice houses were in regular use in ancient Rome, and their growing use soon led to the development of a busy trade in snow and ice crisscrossing Europe, the Mediterranean and parts of western Asia.
Yet desserts made with cold dairy products were not invented until much later. During the Tang Dynasty (AD 616-907), the Chinese made a cold, creamy concoction of buffalo milk, flour, camphor and snow. But while it was easy enough to cool milk down, this mixture proved difficult to freeze. This was simply a matter of physics. Most milk freezes at between
\ -0.535 degrees C and -0.565 degrees C, which is below the freezing point of water; so packing it in frozen water or snow doesn't get milk cold enough to become solid. Surprisingly, the solution to this problem was salt. When salt is added to snow or ice, energy is absorbed from a container of milk, for example, set within the snow or ice, reducing the milk's temperature and creating a basic form of refrigeration of freezing.
No one knows precisely when a mixture of salt and snow or ice was first used to produce ice cream. The earliest recorded references to what we know as ice cream occurred in Europe around 1530. However, it was not until the publication of a cookbook by Mrs Mary Eales in 1718 that recipes showing how to make it appeared in English. At that time, there was considerable variation in the ingredients. Milk, cream and custard were used almost interchangeably; and books of the period recommended including, for example, rose petals, caramel, ginger, lemon, chocolate, parsley and even asparagus.
For many years, historians assumed that it was the aristocracy that were the main consumers of these early ice creams. During the 18th century, for example, a range of beautiful ice cream dishes were created for French King Louis XV and his court. In 1813, US President James Madison's wife arranged for ice creams to be given to guests at her husband's inaugural ball; two years later, the French writer Balzac described the lavish ice cream desserts consumed in the great houses of Paris in his novel Splendeurs et misères des courtisanes. But, especially in 18th-century Naples in Italy, in part because of the relatively easy access to snow, it was also possible for people much lower down the social scale to make, sell and enjoy ice cream. Not only were there shops and cafés selling ice creams, but there were also vendors who sold it along the public roads, and there is evidence to suggest that some families may have made it at home.
However, early ice creams were still quite different from the iced treats we enjoy today. Since the milk, cream or custard was not stirred as it was frozen, it formed icy chunks, resulting in a lumpy, disagreeable texture. In 1843, however, an American called Nancy Johnson designed a hand-turned freezer, which allowed her to make silky smooth ice cream. Her invention consisted of a large container filled with ice and salt, a tightly closed cylinder for the milk or cream and a removable handle, which was rotated to stir the ice cream until properly frozen.
Even with Nancy Johnson's freezer, however, it was only possible to make small batches of ice cream at a time. But in 1926 another American, Clarence Vogt, improved on Johnson's idea with his continuous freezer, which made it possible to produce ice cream on an industrial scale. The inventions of Johnson and Vogt resulted in an explosion in the output of ice cream, which pushed the price down, making ice cream available to everyone everywhere. As more companies started manufacturing their own brands, increased competition led to the standardisation of the commercial product and to more inventive varieties.
followed
the adviceof Hippocrates about cold foods
Simplified: Although Hippocrates warned patients to avoid unhealthy chilled drinks><these icy treatsenjoyedtremendous popularity
Main idea: Hippocrates khuyên bệnh nhân tránh đồ uống lạnh - nhưng món tráng miệng lạnh vẫn rất phổ biến→ người Hy Lạp KHÔNG làm theo lời khuyên của ông.
Plastics affect of our lives - from packaging to cutting-edge technologies in cars and computers, from new textiles to replacements for worn-out parts of our bodies. But none of the applications and innovations we take for granted would have been possible if it weren't for the early scientists who developed and refined the material.
The first man-made plastic, Parkesine, was unveiled in London in 1862. This was an organic material derived from cellulose that once heated could be moulded, and on cooling retained its shape until it was reheated. But because of the high cost of raw materials, production soon came to an end.
During the 19th century, the game of billiards became so popular that thousands of elephants were killed for their ivory-used to make billiard balls. A replacement, celluloid, was found by an American, Hyatt, in 1866. On spilling a bottle of collodion, he discovered that the material congealed into a tough, flexible film. He then used it to produce billiard balls, but they shattered once they hit each other, a problem subsequently solved by the addition of camphor. Celluloid was the first thermoplastic: a substance that can be moulded under heat and pressure. Celluloid was later used in the first flexible photographic film for still and motion pictures.
Rayon, another modified cellulose, was first developed in 1891 by Frenchman Bernigaut, while searching for a way to produce man-made silk. Bernigaut noticed that silkworms secrete a liquid that hardens upon exposure to air and turns into silk. He produced a liquid with similar characteristics, which could the be processed to form fibres that could be spun and would feel like silk. The only problem with his new invention was that it was highly flammable. This problem was later solved by another scientist.
The first completely synthetic man-made substance was discovered in 1907, when Baekeland, a New York chemist, developed a liquid resin that he named Bakelite. All previous plastics could be melted down innumerable times and reformed. Bakelite, however, had the advantage that once shaped, it would never melt or burn. It could also be added to almost any material - such as softwood - and would instantly make it more durable and effective. This new material began to be used for a wide range of products.
Cellophane was discovered by Brandenberger, a Swiss textile engineer. He wanted to apply a clear flexible film to fabrics, such as tablecloths, so that they could be cleaned easily. In 1913 he succeeded by using Viscose (now known as Rayon), but this made the material too stiff to be of any use. Brandenberger saw another potential use, though. He produced sheets of it, which he marketed as Cellophane. This could be used as a clear layer of packaging for any product - the first fully flexible, waterproof wrap.
The 1920s witnessed a 'plastics craze', as the use of cellophane spread throughout the world. Nylon, initially discovered in Germany, was developed in the USA. Its toughness made it a suitable replacement for animal hair in toothbrushes, and when nylon stockings were launched in 1939, they gained great public acceptance.
In 1933 Fawcett and Gibson, two British organic chemists working for the company ICI, discovered polyethylene while testing various chemicals. An attempt to trigger a reaction between ethylene and benzaldehyde under high pressure went wrong when the testing seemed to spring a leak. Upon opening the tube the scientists found a waxy, plastic-like substance, polyethylene. After further experimentation and analysis, they discovered that while the process did have a small leak, the main cause of pressure loss was a polymerization process that combined elements. In 1936, ICI developed a compressor that made possible the production of vast quantities of polyethylene.
Polyethylene played a key role during World War II in the 1940s - first as an underwater cable coating and then as insulation for radar. As polyethylene was very much lighter that the materials traditionally used for the latter purpose, it was now possible for the first time to place radar on planes. This helped in the detection of enemy bombers at night.
After the war the material became very popular with consumers, and it is currently the largest volume plastic in the world, used to make a wide range of common items, such as plastic food storage containers.
