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 really 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 the 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.
To begin with, the writer claims that the ancient Greeks did not have technology to build advanced device. However, the lecturer argues that the Greeks could use small and individual pieces to form a large flat mirrors. As a result, she can not give a nod to the author in terms of the first point.
Secondly, about how long it is required to set the ships on fire, the reading suggests it took ten minutes whereas the speaker disagrees this thought. She thinks that the ship was also made with other materials such as sticky pitch. It was easy to get on fire in a second. Moreover, once the fire is on the ship, the fire could spread to the wood even moving ships. Apparently, the lecturer disproves its counterpart in the reading.
In addition, the author indicates that the Greeks already had flaming arrows so they were not required to build a similar weapon such as burning mirrors. The professor, on the other hand, points out because the Roman were familiar with flaming arrows, the burning mirror could be an unexpected weapon and would be more effective than flaming arrows. Therefore, she reckons the third point is not convincing.
To sum up, the writer and the lecturer hold conflicting views. It is obvious that they will have difficulties finding common ground on this topic.
Grammar and spelling errors:
Line 1, column 212, Rule ID: A_PLURAL[2]
Message: Don't use indefinite articles with plural words. Did you mean 'mirror'?
Suggestion: mirror
... individual pieces to form a large flat mirrors. As a result, she can not give a nod to...
^^^^^^^
Transition Words or Phrases used:
also, apparently, first, however, if, moreover, second, secondly, so, therefore, third, whereas, in addition, such as, as a result, to begin with, to sum up, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 10.0 10.4613686534 96% => OK
Auxiliary verbs: 6.0 5.04856512141 119% => OK
Conjunction : 3.0 7.30242825607 41% => More conjunction wanted.
Relative clauses : 5.0 12.0772626932 41% => More relative clauses wanted.
Pronoun: 17.0 22.412803532 76% => OK
Preposition: 25.0 30.3222958057 82% => OK
Nominalization: 1.0 5.01324503311 20% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1074.0 1373.03311258 78% => OK
No of words: 225.0 270.72406181 83% => More content wanted.
Chars per words: 4.77333333333 5.08290768461 94% => OK
Fourth root words length: 3.87298334621 4.04702891845 96% => OK
Word Length SD: 2.38267823165 2.5805825403 92% => OK
Unique words: 137.0 145.348785872 94% => More unique words wanted.
Unique words percentage: 0.608888888889 0.540411800872 113% => OK
syllable_count: 315.9 419.366225166 75% => OK
avg_syllables_per_word: 1.4 1.55342163355 90% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 5.0 3.25607064018 154% => OK
Article: 9.0 8.23620309051 109% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 5.0 2.5761589404 194% => OK
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 17.0 21.2450331126 80% => The Avg. Sentence Length is relatively short.
Sentence length SD: 42.8144475975 49.2860985944 87% => OK
Chars per sentence: 82.6153846154 110.228320801 75% => OK
Words per sentence: 17.3076923077 21.698381199 80% => OK
Discourse Markers: 13.4615384615 7.06452816374 191% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 3.0 4.33554083885 69% => OK
Sentences with negative sentiment : 7.0 4.45695364238 157% => OK
Sentences with neutral sentiment: 3.0 4.27373068433 70% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.106126287512 0.272083759551 39% => The similarity between the topic and the content is low.
Sentence topic coherence: 0.0291581500794 0.0996497079465 29% => Sentence topic similarity is low.
Sentence topic coherence SD: 0.0420318304911 0.0662205650399 63% => OK
Paragraph topic coherence: 0.056216050013 0.162205337803 35% => Maybe some paragraphs are off the topic.
Paragraph topic coherence SD: 0.0519219007576 0.0443174109184 117% => OK
Essay readability:
automated_readability_index: 9.7 13.3589403974 73% => Automated_readability_index is low.
flesch_reading_ease: 71.14 53.8541721854 132% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 7.6 11.0289183223 69% => OK
coleman_liau_index: 10.09 12.2367328918 82% => OK
dale_chall_readability_score: 7.78 8.42419426049 92% => OK
difficult_words: 47.0 63.6247240618 74% => More difficult words wanted.
linsear_write_formula: 7.5 10.7273730684 70% => OK
gunning_fog: 8.8 10.498013245 84% => OK
text_standard: 8.0 11.2008830022 71% => OK
What are above readability scores?
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Rates: 60.0 out of 100
Scores by essay e-grader: 18.0 Out of 30
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Note: 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.