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.
Last try:06/19/2020 02:11Word Count: 340
The reading and the lecture both are about a weapon used in the war between Greeks and Romans. The author feels that the burning mirror used as a weapon is just an assumption made by people. The lecturer refutes all three points made by the author and argues for each of the assertions.
First of all, the reading says that technology is needed to develop such geometry, to make a huge mirror. However, the professor in the lecture points out that Greek mathematicians know the properties of a parabola and they constructed a large mirror by clubbing small pieces. This proves that technology is not needed when there is intelligence among great people.
Next, the article states that this particular device needs to concentrate on a still object for at least 10 minutes to set fire. Moreover, when the researchers experimented this on a piece of wood discovered that the object has to be still to get fired. On the other hand, the professor argues that the Roman boats were made of other materials apart from wood. On top of that, to fill the gaps between the woods the Romans used a sticky substance called pitch. This pitch material was easy to set on fire within seconds after exposure to a burning mirror and also it can catch fire whether the boat is still or moving.
Finally, the Romans cannot see the burning rays from a mirror. When the fires catch their boats they would be surprised as there is no evidence of burning flames in their reach. It would be possible only when they did not use flaming arrows. This particular point is argued in the reading, mentioning that despite having flaming arrows as the common weapon, they would not have used this device.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2023-02-07 | Celia02200059 | 3 | view |
| 2022-12-27 | nikki07hung | 65 | view |
| 2022-12-27 | nikki07hung | 60 | view |
| 2022-09-07 | Hello GRE | 80 | view |
| 2022-08-05 | bingo | 70 | view |
- several ways of detecting earthquakes 85
- encyclopedias 80
- Do you agree or disagree with the following statement Because the world is changing so quickly people now are less happy or less satisfied with their lives than people were in the past 70
- Burning coal in power plants produces a waste product called coal ash a material that contains small amounts of potentially harmful chemicals Environmentalists in the United States are concerned about the damage such harmful chemicals may be doing to the 80
- In recent years many frog species around the world have declined in numbers or even gone extinct due to changes in their environment These population declines and extinctions have serious consequences for the ecosystems in which frogs live for example fro 85
Grammar and spelling errors:
Line 1, column 192, 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.
...n is just an assumption made by people. The lecturer refutes all three points made ...
^^^
Transition Words or Phrases used:
also, finally, first, however, moreover, second, so, still, apart from, as to, at least, first of all, on the other hand, on top of that
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 13.0 10.4613686534 124% => OK
Auxiliary verbs: 5.0 5.04856512141 99% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 13.0 12.0772626932 108% => OK
Pronoun: 23.0 22.412803532 103% => OK
Preposition: 38.0 30.3222958057 125% => OK
Nominalization: 4.0 5.01324503311 80% => OK
Performance on vocabulary words:
No of characters: 1383.0 1373.03311258 101% => OK
No of words: 295.0 270.72406181 109% => OK
Chars per words: 4.68813559322 5.08290768461 92% => OK
Fourth root words length: 4.14434120667 4.04702891845 102% => OK
Word Length SD: 2.39117884791 2.5805825403 93% => OK
Unique words: 163.0 145.348785872 112% => OK
Unique words percentage: 0.552542372881 0.540411800872 102% => OK
syllable_count: 420.3 419.366225166 100% => 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: 8.0 8.23620309051 97% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 15.0 13.0662251656 115% => OK
Sentence length: 19.0 21.2450331126 89% => OK
Sentence length SD: 30.6141579448 49.2860985944 62% => OK
Chars per sentence: 92.2 110.228320801 84% => OK
Words per sentence: 19.6666666667 21.698381199 91% => OK
Discourse Markers: 9.06666666667 7.06452816374 128% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 4.0 4.33554083885 92% => OK
Sentences with negative sentiment : 8.0 4.45695364238 179% => 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: 0.0987365427623 0.272083759551 36% => The similarity between the topic and the content is low.
Sentence topic coherence: 0.0373931013224 0.0996497079465 38% => Sentence topic similarity is low.
Sentence topic coherence SD: 0.0391759358963 0.0662205650399 59% => OK
Paragraph topic coherence: 0.0633627063729 0.162205337803 39% => Maybe some paragraphs are off the topic.
Paragraph topic coherence SD: 0.0243919678901 0.0443174109184 55% => OK
Essay readability:
automated_readability_index: 10.5 13.3589403974 79% => Automated_readability_index is low.
flesch_reading_ease: 69.11 53.8541721854 128% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 8.3 11.0289183223 75% => OK
coleman_liau_index: 9.92 12.2367328918 81% => OK
dale_chall_readability_score: 7.9 8.42419426049 94% => OK
difficult_words: 62.0 63.6247240618 97% => OK
linsear_write_formula: 10.5 10.7273730684 98% => OK
gunning_fog: 9.6 10.498013245 91% => OK
text_standard: 11.0 11.2008830022 98% => OK
What are above readability scores?
---------------------
It is not exactly right on the topic in the view of e-grader. Maybe there is a wrong essay topic.
Rates: 3.33333333333 out of 100
Scores by essay e-grader: 1.0 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.