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 passage casts doubt on the story that ancient greeks in Syracuse city were able to set the invading Roman ships on fire by using a curved copper mirror that reflected sun light onto the ships. However, the speaker in the lecture argues that the story could have happened in reality. She refutes the claims mentioned in the article.
First and foremost, the author holds that the technology to manufacture such a huge mirror with certain specifications to focus sunlight was not available in the ancient world. Nevertheless, the lecturer brings up the fact that Greeks had a fascinating math skills and it's possible that they could have assembled many pieces to create such gigantic mirror.
Secondly, the writer assumes that such a weapon would have been very impractical and ineffective since it took ten minutes in an experiment to burn a stationary wooden object 30 meters away using a burning mirror. Furthermore, the ships were definitely moving, which would even made it harder to set them on fire. The lecturer challenges this point of view. She illustrates that a highly flammable sticky material was used to seal the wood together in ships and it could start burning within seconds, which would have made the burning mirror an extremely effective defense strategy.
Lastly, the excerpt contends that the Greeks had no reason to build such a weapon because they had already the equally effective flaming arrows. In contrast, the lecturer, on the other hand, indicates that the Romans were familiar with flaming arrows and they would have been ready to put out any fire caused by them. On the contrary. the burning mirror might have been a new innovation which could set ships on fire in an unobserved places. As a result, it would have been surprising and more effective than a traditional flaming arrow.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2020-01-17 | Shiimaaa | 80 | view |
| 2020-01-17 | Shiimaaa | 76 | view |
| 2020-01-09 | mashghanbar | 66 | view |
| 2020-01-08 | Opak Pulup | 78 | view |
| 2020-01-03 | nusybah | 83 | view |
- Scientists are considering the possibility of sending humans to Mars in the coming decades. Although there have been successful manned missions to the Moon in the 1960s and 1970s, Mars is 150 times further away from Earth than the Moon is. Thus the projec 3
- london and german fossils 86
- Sea otters are a small mammal that lives in the waters along North America's west coast from California to Alaska. A few years ago some of the sea otter populations off of the Alaskan coast started to decline rapidly and raised several concerns beca 73
- Because of its remote location, only a few species of plants and animals thrived on Easter Island, and the water surrounding it contained very few fish. Nevertheless, beginning with extremely limited resources on an isolated island, the native people achi 61
- The city enjoys urban forests not only in the city square, the municipal parks, and golf courses, but also along many streets in the city. The forest, boasting almost 700,000 trees, was planted during the late 17th century, but since the 1920s, planting h 3
Grammar and spelling errors:
Line 5, column 358, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
... pieces to create such gigantic mirror. Secondly, the writer assumes that such a...
^^^^^^^
Line 13, column 336, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: The
...y fire caused by them. On the contrary. the burning mirror might have been a new in...
^^^
Line 13, column 373, Rule ID: NEW_XX[1]
Message: Use simply 'innovation'.
Suggestion: innovation
...y. the burning mirror might have been a new innovation which could set ships on fire in an uno...
^^^^^^^^^^^^^^
Line 13, column 435, Rule ID: A_PLURAL[2]
Message: Don't use indefinite articles with plural words. Did you mean 'place'?
Suggestion: place
...ould set ships on fire in an unobserved places. As a result, it would have been surpri...
^^^^^^
Line 13, column 539, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...ctive than a traditional flaming arrow.
^^^^^
Transition Words or Phrases used:
first, furthermore, however, if, lastly, nevertheless, second, secondly, so, in contrast, as a result, on the contrary, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 9.0 10.4613686534 86% => OK
Auxiliary verbs: 10.0 5.04856512141 198% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 13.0 12.0772626932 108% => OK
Pronoun: 23.0 22.412803532 103% => OK
Preposition: 35.0 30.3222958057 115% => OK
Nominalization: 2.0 5.01324503311 40% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1537.0 1373.03311258 112% => OK
No of words: 306.0 270.72406181 113% => OK
Chars per words: 5.02287581699 5.08290768461 99% => OK
Fourth root words length: 4.18244613648 4.04702891845 103% => OK
Word Length SD: 2.516195565 2.5805825403 98% => OK
Unique words: 173.0 145.348785872 119% => OK
Unique words percentage: 0.565359477124 0.540411800872 105% => OK
syllable_count: 471.6 419.366225166 112% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 3.0 3.25607064018 92% => OK
Article: 10.0 8.23620309051 121% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 3.0 2.5761589404 116% => OK
Performance on sentences:
How many sentences: 14.0 13.0662251656 107% => OK
Sentence length: 21.0 21.2450331126 99% => OK
Sentence length SD: 65.1370611457 49.2860985944 132% => OK
Chars per sentence: 109.785714286 110.228320801 100% => OK
Words per sentence: 21.8571428571 21.698381199 101% => OK
Discourse Markers: 9.78571428571 7.06452816374 139% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 5.0 4.19205298013 119% => OK
Sentences with positive sentiment : 8.0 4.33554083885 185% => OK
Sentences with negative sentiment : 4.0 4.45695364238 90% => OK
Sentences with neutral sentiment: 2.0 4.27373068433 47% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.14392249639 0.272083759551 53% => OK
Sentence topic coherence: 0.0436648599899 0.0996497079465 44% => OK
Sentence topic coherence SD: 0.045229893505 0.0662205650399 68% => OK
Paragraph topic coherence: 0.0920157678614 0.162205337803 57% => OK
Paragraph topic coherence SD: 0.0166661054786 0.0443174109184 38% => Paragraphs are similar to each other. Some content may get duplicated or it is not exactly right on the topic.
Essay readability:
automated_readability_index: 13.1 13.3589403974 98% => OK
flesch_reading_ease: 58.62 53.8541721854 109% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 10.3 11.0289183223 93% => OK
coleman_liau_index: 11.84 12.2367328918 97% => OK
dale_chall_readability_score: 8.6 8.42419426049 102% => OK
difficult_words: 76.0 63.6247240618 119% => OK
linsear_write_formula: 11.0 10.7273730684 103% => OK
gunning_fog: 10.4 10.498013245 99% => OK
text_standard: 11.0 11.2008830022 98% => OK
What are above readability scores?
---------------------
Rates: 85.0 out of 100
Scores by essay e-grader: 25.5 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.