A little over 2,200 years ago, the Roman navy attacked the Greek port city of Syracuse. According to some ancient historians, the Greeks defended themselves with an ingenious weapon called a "burning mirror": a polished copper surface curved to focus the Sun's rays onto Roman ships, causing them to catch fire. However, we have several reasons to suspect that the story of the burning mirror is just a myth and the Greeks of Syracuse never rally built such a device.
First, the ancient Greeks were not technologically advanced enough to make such a device. A mirror that would focus sunlight with sufficient intensity to set ships on fire would have to be several meters wide. Moreover, the mirror would have to have a very precise parabolic curvature(a curvature derived from a geometric shape known as the parabola). The technology for manufacturing a large sheet of copper with such specifications did not exist in the ancient world.
Second, the burning mirror would have taken a long time to set the ships on fire. In an experiment conducted to determine whether a burning mirror was feasible, a device concentrating the Sun's rays on a wooden object 30 meters away took ten minutes to set the object on fire: and during that time, the object had to be unmoving. It is unlikely that Roman ships stayed perfectly still for that much time, Such a weapon would therefore have been very impractical and ineffective.
Third, a burning mirror does not seem like an improvement on a weapon that the Greeks already had: flaming arrows. Shooting at an enemy's ships with flaming arrows was a common way of setting the ships on fire. The burning mirror and flaming arrows would have been effective at about the same distance. So the Greeks had no reason to build a weapon like a burning mirror.
Both the reading and listening materials discuss the burning mirror. The reading, to be more specific, claims that it was unlikely for the Greeks of Syracuse to have built the device. On the contrary, the professor holds a different idea and provides evidences that the burning mirror could have been invented by the Greeks.
The reading begins by stating the device was too sophisticated for ancient people. This is challenged by the lecturer, who feels strong that, Greeks did not need such technological advances to build to burning mirror. He further explains that ancient mathematicians could have figured this out by arranging the pieces of mirrors to create fire.
The reading then points out that the device takes too long to be used in wars. The professor, in contrast, asserts that burning mirror could have easily set the opponent's ships on fire in just seconds. He supports his claim by giving information about different materials used to build ships including the pitch, which catches fire very quickly.
The reading finishes by claiming that the Greeks already had a weapon of the same efficiency which was the flaming arrows. The lecturer refutes this and argues that the new device created more advantages for the Greeks. Indeed, the Roman were caught by surprised due to the invisibility of the flames caused by the mirror.
| Post date | Users | Rates | Link to Content |
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| 2020-01-09 | mashghanbar | 66 | view |
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Discourse Markers used:
['if', 'second', 'so', 'then', 'as to', 'in contrast', 'on the contrary']
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance in Part of Speech:
Nouns: 0.230452674897 0.261695866417 88% => OK
Verbs: 0.20987654321 0.158904122519 132% => OK
Adjectives: 0.0658436213992 0.0723426182421 91% => OK
Adverbs: 0.0493827160494 0.0435111971325 113% => OK
Pronouns: 0.0164609053498 0.0277247811725 59% => OK
Prepositions: 0.119341563786 0.128828473217 93% => OK
Participles: 0.0740740740741 0.0370669169778 200% => Less participles wanted.
Conjunctions: 2.54223714993 2.5805825403 99% => OK
Infinitives: 0.0329218106996 0.0208969081088 158% => OK
Particles: 0.0082304526749 0.00154638098197 532% => OK
Determiners: 0.144032921811 0.128158765124 112% => OK
Modal_auxiliary: 0.0123456790123 0.0158828679856 78% => OK
WH_determiners: 0.0123456790123 0.0114777025283 108% => OK
Vocabulary words and sentences:
No of characters: 1349.0 1645.83664459 82% => OK
No of words: 222.0 271.125827815 82% => More content wanted.
Chars per words: 6.07657657658 6.08160592843 100% => OK
Fourth root words length: 3.8600083453 4.04852973271 95% => OK
words length more than 5 chars: 0.400900900901 0.374372842146 107% => OK
words length more than 6 chars: 0.301801801802 0.287516216867 105% => OK
words length more than 7 chars: 0.166666666667 0.187439937562 89% => OK
words length more than 8 chars: 0.108108108108 0.113142543107 96% => OK
Word Length SD: 2.54223714993 2.5805825403 99% => OK
Unique words: 127.0 145.348785872 87% => More unique words wanted.
Unique words percentage: 0.572072072072 0.539623497131 106% => OK
Word variations: 54.9210317009 53.8517498576 102% => OK
How many sentences: 12.0 13.0529801325 92% => OK
Sentence length: 18.5 21.7502111507 85% => OK
Sentence length SD: 24.0177885465 49.3711431718 49% => OK
Chars per sentence: 112.416666667 132.220823453 85% => OK
Words per sentence: 18.5 21.7502111507 85% => OK
Discourse Markers: 0.583333333333 0.878197800319 66% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 3.39072847682 0% => OK
Readability: 48.6801801802 50.5018328374 96% => OK
Elegance: 1.53731343284 1.90840788429 81% => OK
Coherence and Cohesion:
Essay topic to essay body coherence: 0.405194525715 0.549887131256 74% => OK
Sentence sentence coherence: 0.124516168267 0.142949733639 87% => OK
Sentence sentence coherence SD: 0.0381157674631 0.0787303798458 48% => OK
Sentence paragraph coherence: 0.670251824061 0.631733273073 106% => OK
Sentence paragraph coherence SD: 0.0940180586185 0.139662658121 67% => OK
Sentence topic coherence: 0.22251848407 0.266732575781 83% => OK
Sentence topic coherence SD: 0.0713490875252 0.103435571967 69% => OK
Paragraph paragraph coherence: 0.394126262216 0.414875509568 95% => OK
Paragraph paragraph coherence SD: 0.0425740260382 0.0530846634433 80% => OK
Paragraph topic coherence: 0.312363806653 0.40443939384 77% => OK
Paragraph topic coherence SD: 0.0737711402389 0.0528353158467 140% => OK
Task Achievement:
Sentences with positive sentiment : 6.0 4.33554083885 138% => OK
Sentences with negative sentiment : 2.0 4.45695364238 45% => OK
Sentences with neutral sentiment: 4.0 4.26048565121 94% => OK
Positive topic words: 5.0 3.49668874172 143% => OK
Negative topic words: 2.0 3.62251655629 55% => OK
Neutral topic words: 4.0 3.1766004415 126% => OK
Total topic words: 11.0 10.2958057395 107% => OK
What are sentences with positive/Negative/neutral sentiment?
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Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 Out of 30
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Note: This is not the final score. The e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.