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 reading and lecture both talk about a burning mirror. The author of the reading believes that there did not exist such kind of weapon in Greek. The lecturer challenges the claim made by the author. She is of the opinion that the burning mirror is real and there were several reasons for the existence of the burning mirror.
First of all, the author suggests that the ancient Greek was not capable of developing such kind of weapon. It is mentioned that it was very difficult to make several meters wide mirror by copper. The argument is challenged by the lecture. She says it was easy for them to join small size flat copper sheets to produce such wide mirror. Furthermore, she argues that the Greek mathematician was aware of the concept of the parabola.
Secondly, the writer contends that the burning mirror took a long time to set fire on the ship. The article notes the burning mirror took 10 minutes to set fire on a wooden object 30 meters away. And ship must have stayed still perfectly. The lecturer, however, rebuts this by asserting that the ancient ships did not make of only wooden. To elaborate this she bringing up the point that the space between the wood was filled by pitch. She says pitch was set on fire in a second and very rapidly spread whether the ship still or not.
Finally, the author posits that the burning mirror does not like an improvement of the weapon where there was flamming arrow that rapidly set fire in the ship. Moreover, in the article, it is stated that burning mirrors and flamming mirrors are effective at the same distance. The lecturer, on the other hand, posits that burning mirrors are less susceptible and could set fire easily. She puts forth the idea that observer of the enemy ship can easily locate flamming arrows but he can locate the burning mirror which suddenly set fire on the ship and spread the fire rapidly and this was an effective way
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Grammar and spelling errors:
Line 1, column 149, Rule ID: ENGLISH_WORD_REPEAT_BEGINNING_RULE
Message: Three successive sentences begin with the same word. Reword the sentence or use a thesaurus to find a synonym.
...not exist such kind of weapon in Greek. The lecturer challenges the claim made by t...
^^^
Line 9, column 362, Rule ID: HE_VERB_AGR[1]
Message: The pronoun 'she' must be used with a third-person verb: 'brings'.
Suggestion: brings
...e of only wooden. To elaborate this she bringing up the point that the space between the...
^^^^^^^^
Transition Words or Phrases used:
but, finally, first, furthermore, however, if, moreover, second, secondly, so, still, kind of, first of all, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 16.0 10.4613686534 153% => OK
Auxiliary verbs: 4.0 5.04856512141 79% => OK
Conjunction : 10.0 7.30242825607 137% => OK
Relative clauses : 15.0 12.0772626932 124% => OK
Pronoun: 28.0 22.412803532 125% => Less pronouns wanted
Preposition: 37.0 30.3222958057 122% => OK
Nominalization: 4.0 5.01324503311 80% => OK
Performance on vocabulary words:
No of characters: 1582.0 1373.03311258 115% => OK
No of words: 340.0 270.72406181 126% => OK
Chars per words: 4.65294117647 5.08290768461 92% => OK
Fourth root words length: 4.29407602571 4.04702891845 106% => OK
Word Length SD: 2.2123806245 2.5805825403 86% => OK
Unique words: 162.0 145.348785872 111% => OK
Unique words percentage: 0.476470588235 0.540411800872 88% => More unique words wanted or less content wanted.
syllable_count: 484.2 419.366225166 115% => OK
avg_syllables_per_word: 1.4 1.55342163355 90% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 7.0 3.25607064018 215% => Less pronouns wanted as sentence beginning.
Article: 10.0 8.23620309051 121% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 3.0 2.5761589404 116% => OK
Performance on sentences:
How many sentences: 19.0 13.0662251656 145% => OK
Sentence length: 17.0 21.2450331126 80% => The Avg. Sentence Length is relatively short.
Sentence length SD: 39.7445443912 49.2860985944 81% => OK
Chars per sentence: 83.2631578947 110.228320801 76% => OK
Words per sentence: 17.8947368421 21.698381199 82% => OK
Discourse Markers: 6.63157894737 7.06452816374 94% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 2.0 4.19205298013 48% => OK
Sentences with positive sentiment : 5.0 4.33554083885 115% => OK
Sentences with negative sentiment : 10.0 4.45695364238 224% => Less negative sentences wanted.
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: 0.131169413376 0.272083759551 48% => OK
Sentence topic coherence: 0.0476396919423 0.0996497079465 48% => OK
Sentence topic coherence SD: 0.0346387460401 0.0662205650399 52% => OK
Paragraph topic coherence: 0.0899964998534 0.162205337803 55% => OK
Paragraph topic coherence SD: 0.0298495895157 0.0443174109184 67% => OK
Essay readability:
automated_readability_index: 9.4 13.3589403974 70% => 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: 9.39 12.2367328918 77% => OK
dale_chall_readability_score: 7.5 8.42419426049 89% => OK
difficult_words: 65.0 63.6247240618 102% => OK
linsear_write_formula: 6.0 10.7273730684 56% => Linsear_write_formula is low.
gunning_fog: 8.8 10.498013245 84% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
---------------------
Write the essay in 20 minutes.
Rates: 68.3333333333 out of 100
Scores by essay e-grader: 20.5 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.