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 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
The article states that the ancient Greeks of Syracuse did not build a burning mirror and provides three reasons for support. However, the professor explains that the claims in the reading passage are not convincing and refutes the author's reasons.
First, the reading claims that the Greeks did not have advanced technology for manufacturing such a device. The professor refutes this point by saying that the ancient people did not need to build a large sheet of copper. She states that they could make small mirrors, then converted these small pieces to parabolic shape.
Second, the article posits that this weapon would need a long time to destroy the enemy's ships which made it impractical advice. However, the professor says that Roman made their ships from other materials that could catch fire easily. According to the professor, Roman ships contained which in its structure that catch fire quickly.
Third, the reading passage says that the Greeks had flaming arrows which had the same purpose as a burning fire. The professor opposes this point by explaining that Roman soldiers were familiar with the flaming arrows. She argues that a burning mirror would surprise the enemies.
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Transition Words or Phrases used:
first, however, second, so, then, third
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 2.0 10.4613686534 19% => More to be verbs wanted.
Auxiliary verbs: 6.0 5.04856512141 119% => OK
Conjunction : 2.0 7.30242825607 27% => More conjunction wanted.
Relative clauses : 15.0 12.0772626932 124% => OK
Pronoun: 22.0 22.412803532 98% => OK
Preposition: 12.0 30.3222958057 40% => More preposition wanted.
Nominalization: 0.0 5.01324503311 0% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1013.0 1373.03311258 74% => OK
No of words: 194.0 270.72406181 72% => More content wanted.
Chars per words: 5.22164948454 5.08290768461 103% => OK
Fourth root words length: 3.73207559907 4.04702891845 92% => OK
Word Length SD: 2.26754914999 2.5805825403 88% => OK
Unique words: 108.0 145.348785872 74% => More unique words wanted.
Unique words percentage: 0.556701030928 0.540411800872 103% => OK
syllable_count: 289.8 419.366225166 69% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 8.0 8.23620309051 97% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 11.0 13.0662251656 84% => Need more sentences. Double check the format of sentences, make sure there is a space between two sentences, or have enough periods. And also check the lengths of sentences, maybe they are too long.
Sentence length: 17.0 21.2450331126 80% => The Avg. Sentence Length is relatively short.
Sentence length SD: 17.6162021592 49.2860985944 36% => The essay contains lots of sentences with the similar length. More sentence varieties wanted.
Chars per sentence: 92.0909090909 110.228320801 84% => OK
Words per sentence: 17.6363636364 21.698381199 81% => OK
Discourse Markers: 3.54545454545 7.06452816374 50% => More transition words/phrases wanted.
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 1.0 4.33554083885 23% => More positive sentences wanted.
Sentences with negative sentiment : 6.0 4.45695364238 135% => OK
Sentences with neutral sentiment: 4.0 4.27373068433 94% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.117303605739 0.272083759551 43% => OK
Sentence topic coherence: 0.0462633282003 0.0996497079465 46% => OK
Sentence topic coherence SD: 0.0341635426854 0.0662205650399 52% => OK
Paragraph topic coherence: 0.0741248675936 0.162205337803 46% => OK
Paragraph topic coherence SD: 0.0249838938319 0.0443174109184 56% => OK
automated_readability_index: 12.0 13.3589403974 90% => Automated_readability_index is low.
flesch_reading_ease: 62.68 53.8541721854 116% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 8.7 11.0289183223 79% => OK
coleman_liau_index: 12.7 12.2367328918 104% => OK
dale_chall_readability_score: 8.39 8.42419426049 100% => OK
difficult_words: 48.0 63.6247240618 75% => More difficult words wanted.
linsear_write_formula: 8.0 10.7273730684 75% => OK
gunning_fog: 8.8 10.498013245 84% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
Rates: 61.6666666667 out of 100
Scores by essay e-grader: 18.5 Out of 30
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.