Hướng dẫn làm bài"SOSUS: Listening to the Ocean"IELTS READING

Bên cạnh Hướng dẫn làm bài"HELIUM’S FUTURE UP IN THE AIR"IELTS READING, IELTS TUTOR cũng cung cấp thêm PHÂN TÍCH ĐỀ THI 30/5/2020 IELTS WRITING TASK 2 (kèm bài sửa HS đạt 6.5)

SOSUS: Listening to the Ocean

A. The oceans of Earth cover more than 70 percent of the planet’s surface, yet, until quite recently, we knew less about their depths than we did about the surface of the Moon. Distant as it is, the Moon has been far more accessible to study because astronomers long have been able to take at its surface, first with the naked eye and then with the telescope-both instruments that focus light. And, with telescopes tuned to different wavelengths of light, modern astronomers can not only analyze Earth’s atmosphere but also determine the temperature and composition of the Sun or other stars many hundreds of light-years away. Until the twentieth century, however, no analogous instruments were available for the study of Earth’s oceans: Light, which can travel trillions of miles through the vast vacuum of space, cannot penetrate very far in seawater.

B. Curious investigators long have been fascinated by sound and the way it travels in water. As early as 1490, Leonardo da Vinci observed: “If you cause your ship to stop and place the head of a long tube in the water and place the outer extremity to your ear, you will hear ships at a great distance from you.” In 1687, the first mathematical theory of sound propagation was published by Sir Isaac Newton in his Philosophiae Naturalis Principia Mathematica. Investigators were measuring the speed of sound in the air beginning in the mid-seventeenth century, but it was not until 1826 that Daniel Colladon, a Swiss physicist, and Charles Sturm, a French mathematician, accurately measured its speed in the water. Using a long tube to listen underwater (as da Vinci had suggested), they recorded how fast the sound of a submerged bell traveled across Lake Geneva. Their result-1,435 meters (1,569 yards) per second in the water of 1.8 degrees Celsius (35 degrees Fahrenheit) – was only 3 meters per second off from the speed accepted today. What these investigators demonstrated was that water – whether fresh or salt – is an excellent medium for sound, transmitting it almost five times faster than its speed in air.

C. In 1877 and 1878, the British scientist John William Strutt, third Baron Rayleigh, published his two-volume seminal work, The Theory of Sound, often regarded as marking the beginning of the modern study of acoustics. The recipient of the Nobel Prize for Physics in 1904 for his successful isolation of the element argon, Lord Rayleigh made key discoveries in the fields of acoustics and optics that are critical to the theory of wave propagation in fluids. Among other things, Lord Rayleigh was the first to describe a sound wave as a mathematical equation (the basis of all theoretical work on acoustics) and the first to describe how small particles in the atmosphere scatter certain wavelengths of sunlight, a principle that also applies to the behavior of sound waves in water.

D. A number of factors influence how far sound travels underwater and how long it lasts. For one, particles in seawater can reflect, scatter, and absorb certain frequencies of sound – just as certain wavelengths of light may be reflected, scattered, and absorbed by specific types of particles in the atmosphere. Seawater absorbs 30 times the amount of sound absorbed by distilled water, with specific chemicals (such as magnesium sulfate and boric acid) damping out certain frequencies of sound. Researchers also learned that low-frequency sounds, whose long wavelengths generally pass over tiny particles, tend to travel farther without loss through absorption or scattering. Further work on the effects of salinity, temperature, and pressure on the speed of sound has yielded fascinating insights into the structure of the ocean. Speaking generally, the ocean is divided into horizontal layers in which sound speed is influenced more greatly by temperature in the upper regions and by pressure in the lower depths. At the surface is a sun-warmed upper layer, the actual temperature and thickness of which varies with the season. At mid-latitudes, this layer tends to be isothermal, that is, the temperature tends to be uniform throughout the layer because the water is well mixed by the action of waves, winds, and convection currents; a sound signal moving down through this layer tends to travel at an almost constant speed. Next comes a transitional layer called the thermocline, in which temperature drops steadily with depth; as the temperature falls, so does the speed of sound.

E. The U.S. Navy was quick to appreciate the usefulness of low-frequency sound and the deep sound channel in extending the range at which it could detect submarines. In great secrecy during the 1950s, the U.S. Navy launched a project that went by the code name Jezebel; it would later come to be known as the Sound Surveillance System (SOSUS). The system involved arrays of underwater microphones, called hydrophones, that were placed on the ocean bottom and connected by cables to onshore processing centers. With SOSUS deployed in both deep and shallow water along both coasts of North America and the British West Indies, the U.S. Navy not only could detect submarines in much of the northern hemisphere, it also could distinguish how many propellers a submarine had, whether it was conventional or nuclear, and sometimes even the class of sub.

F. The realization that SOSUS could be used to listen to whales also was made by Christopher Clark, a biological acoustician at Cornell University, when he first visited a SOSUS station in 1992. When Clark looked at the graphic representations of sound, scrolling 24 hours day, every day, he saw the voice patterns of blue, finback, minke, and humpback whales. He also could hear the sounds. Using a SOSUS receiver in the West Indies, he could hear whales that were 1,770 kilometers (1,100 miles) away. Whales are the biggest of Earth’s creatures. The blue whale, for example, can be 100 feet long and weigh as many tons. Yet these animals also are remarkably elusive. Scientists wish to observe blue time and position them on a map. Moreover, they can track not just one whale at a time, but many creatures simultaneously throughout the North Atlantic and the eastern North Pacific. They also can learn to distinguish whale calls. For example, Fox and colleagues have detected changes in the calls of finback whales during different seasons and have found that blue whales in different regions of the Pacific Ocean have different calls. Whales firsthand must wait in their ships for the whales to surface. A few whales have been tracked briefly in the wild this way but not for very great distances, and much about them remains unknown. Using the SOSUS stations, scientists can track the whales in real-time and position them on a map.

G. SOSUS, with its vast reach, also has proved instrumental in obtaining information crucial to our understanding of Earth’s weather and climate. Specifically, the system has enabled researchers to begin making ocean temperature measurements on a global scale – measurements that are keys to puzzling out the workings of heat transfer between the ocean and the atmosphere. The ocean plays an enormous role in determining air temperature – the heat capacity in only the upper few meters of the ocean is thought to be equal to all of the heat in the entire atmosphere. For sound waves traveling horizontally in the ocean, speed is largely a function of temperature. Thus, the travel time of a wave of sound between two points is a sensitive indicator of the average temperature along its path. Transmitting sound in numerous directions through the deep sound channel can give scientists measurements spanning vast areas of the globe. Thousands of sound paths in the ocean could be pieced together into a map of global ocean temperatures and, by repeating measurements along the same paths overtimes, scientists could track changes in temperature over months or years.

H. Researchers also are using other acoustic techniques to monitor climate. Oceanographer Jeff Nystuen at the University of Washington, for example, has explored the use of sound to measure rainfall over the ocean. Monitoring changing global rainfall patterns undoubtedly will contribute to understanding major climate change as well as the weather phenomenon known as El Niño. Since 1985, Nystuen has used hydrophones to listen to rain over the ocean, acoustically measuring not only the rainfall rate but also the rainfall type, from drizzle to thunderstorms. By using the sound of rain underwater as a “natural” rain gauge, the measurement of rainfall over the oceans will become available to climatologists.

IELTS TUTOR dịch câu hỏi:

• Trong quá khứ, những khó khăn của nghiên cứu thực hiện trên Mặt trăng dễ hơn nhiều so với ở đại dương.

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• difficulties (n) sự khó khăn 
• carry out (v) tiến hành 
• much + adj so sánh thể hiện sự nhấn mạnh 
• that để thay thế cho research 

IELTS TUTOR dịch câu hỏi:

• Công nghệ ánh sáng tương tự được sử dụng trong việc khảo sát mặt trăng có thể được sử dụng trong lĩnh vực đại dương.

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• investigation (n) sự điều tra 
• employ (v) sử dụng   >> IELTS  TUTOR  hướng  dẫn  Cách dùng & Word form của "employ"

IELTS TUTOR dịch câu hỏi:

• Nghiên cứu về độ sâu của đại dương bằng phương pháp sóng âm tốn nhiều thời gian hơn.

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• Research (n) nghiên cứu   >> IELTS  TUTOR  hướng  dẫn  Cách dùng "RESEARCH" như Noun & Verb tiếng anh
• time-consuming (adj) mất thời gian   >> IELTS  TUTOR  hướng  dẫn  Cách dùng tính từ"time-consuming"&"consuming"tiếng anh ...

IELTS TUTOR dịch câu hỏi:

• Công nghệ hydrophones có thể phát hiện loại mưa.

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• detect (v) phát hiện 
• precipitation (n) lượng mưa  >> IELTS  TUTOR  hướng  dẫn Cách dùng danh từ"precipitation"tiếng anh 

The Reading Passage has 8 paragraphs A-H.

Which paragraph contains the following information?

IELTS TUTOR dịch câu hỏi:

• Các yếu tố ảnh hưởng đến sự truyền âm thanh trong đại dương.

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• Element (n) yếu tố
• transmission (n) sự truyền 

IELTS TUTOR dịch câu hỏi:

• Mối quan hệ giữa khí hậu toàn cầu và nhiệt độ đại dương.

IELTS TUTOR dịch câu hỏi:

• Ví dụ về cách công nghệ âm thanh giúp mọi người nghiên cứu đại dương và các sinh vật trong đó.

IELTS TUTOR dịch câu hỏi:

• Sự truyền âm thanh dưới nước tương tự như sự truyền âm thanh trong bất kỳ điều kiện nào.

IELTS TUTOR dịch câu hỏi:

• Ai trong số những người sau đây nghiên cứu chuyên sâu tốc độ âm thanh?

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• dedicate (v) đầu tư thời gian/công sức làm gì   >> IELTS  TUTOR  hướng  dẫn Cách dùng động từ "dedicate" tiếng anh

IELTS TUTOR dịch câu hỏi:

• Ai đã giải thích rằng lý thuyết về bước sóng ánh sáng hoặc âm thanh có ý nghĩa trong nước?

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• significant (a) nhiều, rõ ràng 

IELTS TUTOR dịch câu hỏi:

• Theo Fox và các đồng nghiệp, sự thay đổi cách gọi của cá voi lưng vây diễn ra theo mô hình nào

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• pattern (n) hình thái  >> IELTS  TUTOR  hướng  dẫn  Cách dùng danh từ"pattern"tiếng anh

IELTS TUTOR dịch câu hỏi:

• Công nghệ SOSUS kiểm tra cá voi bằng cách nào?

  • A. Theo dõi tất cả các loại cá voi trong đại dương

    B. Theo dõi các đàn cá voi cùng một lúc

    C. Chỉ theo dõi cá voi lưng gù trong đại dương

    D. Theo dõi cá voi bằng cách sử dụng nhiều đồ dùng hoặc thiết bị

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• inspect (v) điều tra 
• appliances (n) đồ dùng 

IELTS TUTOR dịch câu hỏi:

• Các nhà khoa học có thể kiểm tra điều gì thông qua việc giám sát dọc theo một tuyến đường lặp lại?
  • A. Nhiệt độ của bề mặt truyền qua
  • B. Nhiệt độ của đáy đại dương sâu nhất
  • C. Sự thay đổi của nhiệt độ
  • D. Dữ liệu cố định về nhiệt độ

IELTS TUTOR lưu ý từ mới trong câu hỏi:

• repeated (adj) lặp lại 
• pass (v) truyền qua   >> IELTS  TUTOR  hướng  dẫn  Cách dùng động từ "pass" tiếng anh
• Variation (n) sự thay đổi 
• Fixed (a) cố định

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