- Fri Jun 03, 2016 2:05 pm
#26112
Passage Discussion
Paragraph One:
The author begins by presenting an apparently common misconception - that the glass in windows changes over time, like a very thick liquid. This mistaken belief, sometimes used to explain old rippled windows, may be based on the fact that the atoms in both liquid and solid glass lack a fixed crystal structure. Rather than a freezing point, glass has a “transition temperature,” which tends to fall within a range of several hundred degrees Celsius, below which glass becomes a solid despite its lack of a fixed atomic crystal structure.
Paragraph Two:
Here, the author turns to evidence refuting the belief that medieval cathedral stained glass is thicker at the bottom because of a very slow flow over the past several centuries. Gravity can cause some solids to slightly flow, but according to the research of Edgar Zanotto, the amount of time needed to achieve any noticeable flow would be greater than the amount of time that the universe has been in existence.
Paragraph Three:
Continuing the discussion of Zanotto’s study, the author provides that any flow that might take place would depend on the glass’ chemical composition, and would likely require several trillion years to achieve any noticeable flow. So, even if medieval stained glass had impurities that would speed the process somewhat, a few centuries would not be enough time for the effect to occur.
Paragraph Four:
In the closing paragraph, the author provides another explanation for the increasing thickness that is often found in medieval glass: in the 1800’s, glass was cut from discs made from flattened glass globes, and the natural way to situate uneven, rippled glass was to have the thick part at the bottom. Since then, glass has become much more uniform and flat, first being made from the melt on a rod, then, more recently, by floating glass in liquid form over tin.
VIEWSTAMP Analysis:
The Viewpoints represented in the passage are those of the author, and of those who misunderstand the structure of glass.
The Structure of the passage is as follows:
The author’s Tone is academic and well-reasoned.
The author’s Argument is that the manufacturing process of the time was the true cause of a phenomenon that has been persistently misconstrued.
The Main Point of the passage is that despite a common misconception about glass slowly flowing downwards, allegedly causing medieval windows to be thicker at the bottom, the change in thickness is actually attributable to the glassmaking process of the era.
Paragraph One:
The author begins by presenting an apparently common misconception - that the glass in windows changes over time, like a very thick liquid. This mistaken belief, sometimes used to explain old rippled windows, may be based on the fact that the atoms in both liquid and solid glass lack a fixed crystal structure. Rather than a freezing point, glass has a “transition temperature,” which tends to fall within a range of several hundred degrees Celsius, below which glass becomes a solid despite its lack of a fixed atomic crystal structure.
Paragraph Two:
Here, the author turns to evidence refuting the belief that medieval cathedral stained glass is thicker at the bottom because of a very slow flow over the past several centuries. Gravity can cause some solids to slightly flow, but according to the research of Edgar Zanotto, the amount of time needed to achieve any noticeable flow would be greater than the amount of time that the universe has been in existence.
Paragraph Three:
Continuing the discussion of Zanotto’s study, the author provides that any flow that might take place would depend on the glass’ chemical composition, and would likely require several trillion years to achieve any noticeable flow. So, even if medieval stained glass had impurities that would speed the process somewhat, a few centuries would not be enough time for the effect to occur.
Paragraph Four:
In the closing paragraph, the author provides another explanation for the increasing thickness that is often found in medieval glass: in the 1800’s, glass was cut from discs made from flattened glass globes, and the natural way to situate uneven, rippled glass was to have the thick part at the bottom. Since then, glass has become much more uniform and flat, first being made from the melt on a rod, then, more recently, by floating glass in liquid form over tin.
VIEWSTAMP Analysis:
The Viewpoints represented in the passage are those of the author, and of those who misunderstand the structure of glass.
The Structure of the passage is as follows:
- Paragraph One: Introduce a common myth about glass’ structure, and briefly explain varying atomic structures and the concept of transition temperature.
Paragraph Two: Outline a study that debunks the myth presented in the first paragraph.
Paragraph Three: Present further evidence that the thickness of medieval windows did not result from glass flowing downwards.
Paragraph Four: Provide an alternative cause for the difference in thickness described in the preceding paragraphs. This is the Main Point of the passage.
The author’s Tone is academic and well-reasoned.
The author’s Argument is that the manufacturing process of the time was the true cause of a phenomenon that has been persistently misconstrued.
The Main Point of the passage is that despite a common misconception about glass slowly flowing downwards, allegedly causing medieval windows to be thicker at the bottom, the change in thickness is actually attributable to the glassmaking process of the era.