Starting in the 1960s and continuing until the 1980s, sailors in Russian submarines patrolling the North Atlantic and Arctic Ocean would occasionally hear strange sounds. These underwater noises reminded the submarine crews of frog croaks, so they called the sounds “quackers” (from the Russian word for frog sounds). The sources of the sound seemed to be moving with great speed and agility; however, the submarines’ sonar (a method of detecting objects underwater) was unable to detect any solid moving objects in the area. There are several theories about what might have caused the odd sounds.
The first theory suggests that the strange noises were actually the calls of male and female ocra whales during a courtship ritual. Orca whales are known to inhabit the areas where the submarines were picking up the bizarre noises. Orcas have been studied extensively, and the sounds they make when trying to attract a male are similar to those that the submarines were detecting.
A second idea is that the sounds were caused by giant squid. Giant squids are giant marine invertebrates that live deep in the ocean and prey on large fish. They are difficult to detect by sonar because they have soft bodies with no skeleton. Not much is known about giant squid behavior, but their complex brains suggest they are intelligent animals. It is possible they have the ability to emit sound, and perhaps they approached the submarines out of curiosity.
A third theory suggests the Russian submarines were picking up stray sounds from some military technology, like another country’s submarines that were secretly patrolling the area. Perhaps the foreign submarines did not register on sonar because they were using a kind of technology specifically designed to make them undetectable by sonar. The strange froglike sounds may have been emitted by the foreign submarines unintentionally.
The reading states the explanation of a sound called “quackers” heard by Russian submarines and provides three reasons of support. However, the professor mentions that all the theories have problems explaining the possible causes of the sound and refutes each of the author's claims.
First, the article claims that the sound came from the call of male and female Orcas because they inhabit the same area where the submarine was picking up the strange sound. Moreover, scientists discovered that the sounds were heard are so similar to those made by whales in the courtship process. The professor refutes this point by saying that this theory is unlikely to be truth. He states that most Orcas live on the surface rather than in the deep of the ocean, and so the sound would not have been detected by the submarine on the bottom of the sea.
Second, the reading posits that giant squids could have caused the sound. Furthermore, these animals are difficult to be detected by the sonar due to the soft body. However, the professor says that in 1960's some squid's sound was heard, but later in 1980's its sound disappeared. According to the professor, there is no reason to hear now the sound and stop listening years ago. He says that this theory does not make sense, and thus the sound has to be from another source.
Finally, the last theory suggested that the quackers were made by other military submarines patrolling the area, yet the technology they used was undetected by the Russian's sonar. The professor opposes this point by explaining that non submarine can move so quickly to avoid to be detected by another one. The professor points out that even though submarines were provided with so sophisticate technology, they always make an engine noise easy to hear. Thus, this theory about other submarines cannot be supported.
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the sounds were heard are so similar to those made by whales
the sounds which were heard are so similar to those made by whales
Attribute Value Ideal
Score: 25 in 30
Category: Very Good Excellent
No. of Grammatical Errors: 1 2
No. of Spelling Errors: 0 2
No. of Sentences: 15 12
No. of Words: 311 250
No. of Characters: 1490 1200
No. of Different Words: 165 150
Fourth Root of Number of Words: 4.199 4.2
Average Word Length: 4.791 4.6
Word Length SD: 2.354 2.4
No. of Words greater than 5 chars: 100 80
No. of Words greater than 6 chars: 71 60
No. of Words greater than 7 chars: 47 40
No. of Words greater than 8 chars: 32 20
Use of Passive Voice (%): 0 0
Avg. Sentence Length: 20.733 21.0
Sentence Length SD: 6.648 7.5
Use of Discourse Markers (%): 0.8 0.12
Sentence-Text Coherence: 0.35 0.35
Sentence-Para Coherence: 0.548 0.50
Sentence-Sentence Coherence: 0.08 0.07
Number of Paragraphs: 4 4