IELTS Kindly Submit Your Details, Then You Can Start Your Test !! Name Mobile No. Email City State Country Course 1. ……………….. (provides access to trapped water). Label the diagram below.Choose NO MORE THAN THREE WORDS from the passage for each answer. 1. water table well 2. explosive fountain 3. extraction pump 4. natural spring 2. ……………….. (due to the lower land level) Label the diagram below.Choose NO MORE THAN THREE WORDS from the passage for each answer. 1. confined aquifer 2. natural spring 3. (an) extraction pump 4. either 3. flowing artesian well (looks like ………………..) Label the diagram below.Choose NO MORE THAN THREE WORDS from the passage for each answer. 1. (an) extraction pump 2. (an) explosive fountain 3. confined aquifer 4. natural spring 4. ……………….. is necessary to access this water source Label the diagram below.Choose NO MORE THAN THREE WORDS from the passage for each answer. 1. (an) explosive fountain 2. (an) extraction pump 3. confined aquifer 4. either 5. It continues to protect water as it is being transported. Classify the following statements as referring to A reverse osmosis B UV light treatment C chlorination D distillation 6. It is particularly useful during emergencies. Classify the following statements as referring to A reverse osmosis B UV light treatment C chlorination D distillation 7. It uses a physical barrier to separate unwanted matter from water. Classify the following statements as referring to A reverse osmosis B UV light treatment C chlorination D distillation 8. It prevents bacteria from reproducing. A reverse osmosis B UV light treatment C chlorination D distillation 9. It removes all mineral particles. Classify the following statements as referring to A reverse osmosis B UV light treatment C chlorination D distillation 10. It produces a lot of waste water. Classify the following statements as referring to A reverse osmosis B UV light treatment C chlorination D distillation 11. Which TWO of the following claims about water are made by the writer? Choose TWO letters, A–E.Write the correct letters in boxes 12 and 13 on your answer sheet. A Bottled water is overpriced. B Tap water may not have a nice flavour. C Most people should drink bottled water. 12. Which TWO of the following claims about water are made by the writer? Choose TWO letters, A–E.Write the correct letters in boxes 12 and 13 on your answer sheet. A Bottled water is overpriced. B Tap water may not have a nice flavour. C Most people should drink bottled water. D Tap water is usually safe to drink. 13. A description of how international style buildings look on the inside THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Reading Passage 1 has six paragraphs, A–F.Which paragraph contains the following information?Write the correct letter, A–F, in boxes 14–19 on your answer sheet. A (C) B (D) C (A) D (F) 14. A reference to institutions that didn’t like to use international style buildings THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Reading Passage 1 has six paragraphs, A–F.Which paragraph contains the following information?Write the correct letter, A–F, in boxes 14–19 on your answer sheet. A ( B) B (C) C (D) D (E) 15. A reason why architects didn’t like the international style THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Reading Passage 1 has six paragraphs, A–F.Which paragraph contains the following information?Write the correct letter, A–F, in boxes 14–19 on your answer sheet. A (E) B (C) C (A) D (F) 16. A building which combined art deco and international features THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Reading Passage 1 has six paragraphs, A–F.Which paragraph contains the following information?Write the correct letter, A–F, in boxes 14–19 on your answer sheet. A (B) B (D) C (E) D (F) 17. Types of materials commonly used in international style buildings THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Reading Passage 1 has six paragraphs, A–F.Which paragraph contains the following information?Write the correct letter, A–F, in boxes 14–19 on your answer sheet. A (B) B (D) E (F) F (C) 18. An architectural feature previously associated with prominent organisations THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Reading Passage 1 has six paragraphs, A–F.Which paragraph contains the following information?Write the correct letter, A–F, in boxes 14–19 on your answer sheet. A (B) B (C) C (E) D (D) 19. The development of the international style was prompted by an increased need for ……………….. buildings THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Complete the sentences below.Choose NO MORE THAN THREE WORDS from the passage for each answer.Write your answers in boxes 20–24 on your answer sheet. A commercial and function B function and practicality c (non-essential) ornamentation D commercial and civics 20. Designers used hardly any ……………….. on international style buildings. THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Complete the sentences below.Choose NO MORE THAN THREE WORDS from the passage for each answer.Write your answers in boxes 20–24 on your answer sheet. A (non-essential) ornamentation B function (and) practicality C commercial and civic D wealth (and) prestige/prestige (and) wealth 21. International style buildings are easily identified from the outside because of the ……………….. . THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Complete the sentences below.Choose NO MORE THAN THREE WORDS from the passage for each answer.Write your answers in boxes 20–24 on your answer sheet. A (non-essential) ornamentation B wealth (and) prestige/prestige (and) wealth C (recognisable/ recognizable) ribbon design D commercial and civic 22. Demonstration of ……………….. and ……………….. was often an important factor in the design of old-style buildings. THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Complete the sentences below.Choose NO MORE THAN THREE WORDS from the passage for each answer.Write your answers in boxes 20–24 on your answer sheet. A function (and) practicality B commercial and civic C wealth (and) prestige/prestige (and) wealth D (recognisable/ recognizable) ribbon design 23. The similarity of international style constructions reflected the concern of architects with ……………….. and THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Reading Passage 1 has six paragraphs, A–F.Which paragraph contains the following information?Write the correct letter, A–F, in boxes 14–19 on your answer sheet. A (non-essential) ornamentation B commercial and civic C wealth (and) prestige/prestige (and) wealth D function (and) practicality 24. Some people did not like the international style because they felt it focused too much on THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building (1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Choose the correct letter, A, B, C, or D.Write the correct letter in boxes 12–13 on your answer sheet. A the public sector B differences between people C new ideas D making money. 25. In the mid-1970s THE INTERNATIONAL STYLEA In the early decades of the 20th century, many Western cities experienced a steep rise indemand for commercial and civic premises, due to population growth and expansion of the white-collarprofessions. At the same time, architects were growing discontented with the ornamental spirals anddecorative features in the prevailing design ethos of art deco or art moderne. Once considered theheight of sophistication, these styles were quickly becoming seen as pretentious and old-fashioned. Inthis confluence of movements, a new style of architecture emerged. It was simple, practical and strong;a new look for the modern city and the modern man. It was named ‘the international style’.B Although the international style first emerged in Western Europe in the 1920s, it found its fullestexpression in American architecture and was given its name in a 1932 book of the same title. The firsthints of it in America can be seen on the Empire State Building in New York City, which was completedin 1931. The top of the building, with its tapered crown, is decidedly art deco, yet the uniform shaftof the lower two thirds represents a pronounced step in a new direction. Later efforts, such as theUnited Nations Secretariat building a(1952) and the Seagram Building (1954) came to exemplify the‘true’ international style.C The architects of the international style broke with the past by rejecting virtually all non-essentialornamentation. They created blockish, flat-roofed skyscrapers using steel, stone and glass. A typicalbuilding facade in this style has an instantly recognisable ribbon design, characterised by strips of floorto-ceiling windows separated by strips of metal panelling. Interiors showcased open spaces and fluidmovements between separate areas of the building.D Fans of the international style of modern buildings celebrated their sleek and economicalcontribution to modern cityscapes. While pre-modern architecture was typically designed to display thewealth and prestige of its landlords or occupants, the international style in some ways exhibited a moreegalitarian tendency. As every building and every floor looked much the same, there was little attemptto use these designs to make a statement. This focus on function and practicality reflected a desire inmid-century Western cities to ‘get on with business’ and ‘give everyone a chance’, rather than laudingthe dominant and influential institutions of the day through features such as Romanesque columns.E Detractors, however, condemned these buildings for showing little in the way of human spirit orcreativity. For them, the international style represented not an ethos of equality and progress, but anobsession with profit and ‘the bottom line’ that removed spiritual and creative elements from public lifeand public buildings. Under the dominance of the international style, cities became places to work anddo business, but not to express one’s desires or show individuality. It is perhaps telling that while banksand government departments favoured the international style, arts organisations rarely opted for itsausterity.F By the mid-1970s, the international style was ubiquitous across key urban centres, dominatingskylines to such an extent that many travellers complained they could get off a plane and not knowwhere they were. By their nature, buildings in this style demanded very little of architects in the way ofimagination, and a younger generation of designers was yearning to express their ideas and experimentin novel and unexpected ways. The outcome was a shift toward postmodernism, which celebratedmuch of what the international style had dismissed: decoration, style without function, and an overallsense of levity. By the turn of the 1980s, the international style was considered outdated and was fallingrapidly out of favour.Choose the correct letter, A, B, C, or D.Write the correct letter in boxes 12–13 on your answer sheet. A the best architects were no longer using the international style. B there was a lot of international style architecture in major cities. C young architects were becoming interested in the international style. D people visited cities specifically to see international style buildings. 26. For more than 2000 years people have wondered why raising the 27 ………………... of cold water before cooling it results THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Complete the summary using the list of words, A–O, below.Write the correct letter, A–O, in boxes 29–34 on your answer sheet. A melt B temperature C acceleration D matter 27. in more rapid cooling. At first researchers thought that a warm container created its own icy 28 ………………... which THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Complete the summary using the list of words, A–O, below.Write the correct letter, A–O, in boxes 29–34 on your answer sheet. A centre B factor C hollow D acceleration 28. made the water freeze faster, but comparisons with containers resting on a dry 29 ………………... indicated that this THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Complete the summary using the list of words, A–O, below.Write the correct letter, A–O, in boxes 29–34 on your answer sheet. A surface B element C process D difference 29. was inaccurate. Evaporation of water proved not to be a 30 ……………….... . Temperature measurements showed that, THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Complete the summary using the list of words, A–O, below.Write the correct letter, A–O, in boxes 29–34 on your answer sheet. A element B acceleration C factor D centre 30.temperature drops the most at the top and sides of the container. Provided there is a temperature 31………………..., the THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Complete the summary using the list of words, A–O, below.Write the correct letter, A–O, in boxes 29–34 on your answer sheet. A circulation B difference C hollow D matter 31. water will continue to circulate and to cool down. Cooler water will have less water 32………………..., and thus a slower THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Complete the summary using the list of words, A–O, below.Write the correct letter, A–O, in boxes 29–34 on your answer sheet. A circulation B acceleration C matter D element 32. rate of freezing. If ice forms on the top of the water, this will further slow the 33………………... of freezing, but if it forms THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Complete the summary using the list of words, A–O, below.Write the correct letter, A–O, in boxes 29–34 on your answer sheet. A process B melt C centre D hollow 33. The Mpemba Effect cannot be seen when comparing liquids with an extreme temperature difference . THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Do the following statements agree with the information given in Reading Passage 3?In boxes 35–40 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this A TRUE B FALSE C NOT GIVEN D None 34. Osborne and Mpemba’s results are still widely accepted today. THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Do the following statements agree with the information given in Reading Passage 3?In boxes 35–40 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this A TRUE B FALSE C NOT GIVEN D None 35. The size of the container does not alter the Mpemba Effect. THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Do the following statements agree with the information given in Reading Passage 3?In boxes 35–40 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this A TRUE B FALSE C NOT GIVEN D NONE 36. Osborne and Mpemba experimented on both pure and impure water. THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Do the following statements agree with the information given in Reading Passage 3?In boxes 35–40 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this A TRUE B FALSE C NOT GIVEN D NONE 37. One variable is the timing of containers in a freezer. THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Do the following statements agree with the information given in Reading Passage 3?In boxes 35–40 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this A TRUE B FALSE C Not Given D None 38. Physicists now agree that supercooling accounts for the Mpemba Effect. THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Do the following statements agree with the information given in Reading Passage 3?In boxes 35–40 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this A True B False C Not Given D None 39. The Mpemba Effect is best summed up as the observation that THE MPEMBA EFFECTIn 300 BC, the famous philosopher Aristotle wrote about a strange phenomenon that he hadobserved: “Many people, when they want to cool water quickly, begin by putting it in the sun.” Otherphilosophers over the ages noted the same result, but were unable to explain it. In 1963, a youngTanzanian student named Erasto Mpemba noticed that the ice cream he was making froze fasterif the mix was placed in the freezer while warm than if it were at room temperature. He persisted inquestioning why this occurred, and eventually physicist Denis Osborne began a serious investigationinto what is now known as the Mpemba Effect. He and Mpemba co-authored a paper in New Scientistin 1969, which produced scientific descriptions of some of the many factors at work in freezing water.It was initially hypothesised that the warm bowl melted itself a place in the ice on the freezer shelf,thus embedding its base in a ‘nest’ of ice, which would accelerate freezing. The hypothesis wastested by comparing the result when bowls of warm water were placed on ice and on a dry wire shelf;this demonstrated that the ice nest actually had little effect. A second suggestion was that the warmerwater would be evaporating at its surface, thus reducing the volume needing to be frozen, but thisidea was also shown to be insignificant. Thermometers placed in the water showed that the coolerwater dropped to freezing temperature well before the warmer bowlful, and yet the latter always frozesolid first. Experiments at different temperatures showed that water at 50C took longest to freeze in aconventional freezer, while water initially at 350C was quickest.On further examination, an explanation for this paradox began to emerge. Losing heat from the wateroccurs at the points where it is in touch with the colder atmosphere of the freezer, namely the sides ofthe bowl and the water surface. A warm surface will lose heat faster than a cold one because of thecontrast between the temperatures; but of course there is more heat to be lost from one bowl than theother! If the surface can be kept at a higher temperature, the higher rate of heat loss will continue. Aslong as the water remains liquid, the cooling portion on top will sink to the bottom of the bowl as thewarmer water below rises to take its place. The early freezing that may occur on the sides and baseof the container will amplify the effect.The bowl that is more uniformly cold will have far less temperature difference so the water flowwill be minimal. Another inhibiting factor for this container is that ice will also form quite quickly onthe surface. This not only acts as insulation, but will virtually stop the helpful effects of the watercirculating inside the bowl. Ultimately, the rate of cooling the core of this body of water becomesso slow that the other warmer one is always fully frozen first. While there are limitations to thiscomparison (for example, we would not see such a result if one quantity were at 10C and another at990C) this counter-intuitive result does hold true within the 5–350C range of temperatures indicatedpreviously.Since this paper was published, the validity of the research findings has been questioned by anumber of reviewers. They point out that the initial experimental question was not clearly defined; forexample, the researchers needed to decide on exactly what constituted freezing the water. They alsostate that the rate at which water freezes depends on a large number of variables.Container size is one of these; for the Mpemba Effect to be noticed, the container must be largeenough to allow a free circulation of water to take place, yet small enough for the freezing areas ofthe side and base to be effective at extracting heat too. Secondly, research at a University in St Louis,Missouri, suggests that the Mpemba Effect may be affected by water purity, or by dissolved gas inthe water. Distilled water is totally free of the particles that are common in normal drinking wateror mineral water. When suspended in water, these particles may have a small effect on the speedof cooling, especially as ice molecules tend to expel them into the surrounding water, where theybecome more concentrated. Just as salt dissolved in water will raise the boiling point and lower thetemperature at which it freezes, the researchers found that the final portion of ordinary water neededextra cooling, below zero, before all was frozen solid.One more factor that can distort the effect is observed if the bowls are not placed simultaneously intothe same freezer. In this case, the freezer thermostat is more likely to register the presence of a hotterbowl than a colder one, and therefore the change in internal temperature causes a boost of freezingpower as the motor is activated.The Mpemba Effect is still not fully understood, and researchers continue to delve into its underlyingphysics. Physicists cannot reach consensus. Some suggest that supercooling1 is involved; othersthat the molecular bonds in the water molecules affect the rate of cooling and freezing of water. A2013 competition to explain the phenomenon run by the Royal Society of Chemistry attracted morethan 22,000 entries, with the winning one suggesting supercooling as an important factor so it seemsthe question and its underlying explanation continue to fascinate.Choose the correct letter, A, B, C or D.Write the correct letter in box 40 on your answer sheet. A ice cream freezes at different temperatures. B different sources of heat result in water cooling at different rates. C salt water freezes at a lower temperature than ordinary water. D warmer water can freeze faster than colder water. 40 In paragraph one, the writer suggests that companies could consider The general assumption is that older workers are paid more in spite of, rather than becauseof, their productivity. That might partly explain why, when employers are under pressure tocut costs, they persuade a 55-year old to take early retirement. Take away seniority-basedpay scales, and older workers may become a much more attractive employment proposition.But most employers and many workers are uncomfortable with the idea of reducingsomeone’s pay in later life – although manual workers on piece-rates often earn less as theyget older. So retaining the services of older workers may mean employing them in differentways. A. abolishing pay schemes that are based on age B. avoiding pay that is based on piece-rates. C .increasing pay for older workers. D .equipping older workers with new skills Warning: Undefined array key "correct_answer_logic" in /home/kaling/public_html/kalingaplus/wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php on line 451 Time's up