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SONAR, as it is most commonly known as has been around since the beginning of time. Animals have used this technique and survived because of it for millions of years. Among the most common are bats and dolphins.
Daniel Colloden used a bell to measure the speed of sound underwater in 1822. After the Titanic sunk, the idea of using sound underwater to locate objects, primarily icebergs, was taken up by inventors. Lewis Richardson, a meteorologist, was the first to file a patent for an echo locator one month after the Titanic had sunk. In 1914, Reginald Fessenden made an experimental unit, which was able to detect icebergs within a two-mile range, but it could not determine the direction.
During World War I, with the invention of submarines came the need to locate them. Research of underwater sound location was a primary focus for the British. Both the U.S. and Britain were researching what would be Sonar, and it was kept secret throughout the war. By 1922, units were being produced and by 1923, they were being equipped to naval vessels.
Throughout the war, Britain referred to this underwater locator as ASDIC, which was the Anti-Submarine Detection Investigation Committee. This committee, however, never existed. The name was just a cover-up to keep the actual detector secret. The term SONAR came from the Americans, who used it as the equivalent of RADAR. The term ASDIC was terminated in 1948 when NATO was formed and signals were being standardized.
Sonar utilizes sound propagation to detect objects, navigate, and communicate. Through acoustic location, Sonar can be used to find an object and tell how far away that object is.
As shown above, a transmitter sends out a pulse of sound towards an object, the sound wave is then reflected off of the object and sent back to the source.
The distance of the object is determined by the amount of time it takes for a reflection to return after the pulse is sent out. This can be affected by several factors such as the density of the media which the sound is traveling through and if the object itself is moving or not.
To find the direction of the object, several receivers are used to signal when a reflection passes by them.
The above picture shows an initial wave being sent out in all directions.
The Project Office was created in 1982 and a contract with the Australian Submarine Corporation Pty Ltd (ASC) was signed in June 1987. The first submarine, HMAS Collins, was launched in August 1993. This was a significant achievement for ASC and its subcontractors given that the production program commenced at widely separated sites in 1987 and ran in parallel with design and system development (ANAO, 1998).
Throughout the years submarine technology has advanced throughout the years from the original military submarine the turtle to the German u boats during WWII modern nuclear power submarines that we have today. These developments have required a lot of technological improvements. To make the u boats work the Germans need better battery and electrical motor technologies and the nuclear submarine obviously needed nuclear technology. Submarines have always been an innovative way to win the navel war.
...t was not for these precursors then the continuation of unrestricted submarine warfare might still be a threat to the vessels that now transport hundreds of thousands of people all over the globe.
The weapon was designed to lock onto the loudest noise after a run of 400m from its launch. This often proved to be the U-boat itself and standard issue-orders were to dive immediately to depth of 60m after launch from a bow tube while a stern shot was to be followed by a complete silence in the boat. Two U-boats were almost certainly lost when hit by one of their own T5 torpedoes, U-972 in Dec 1943 and U-377 in Jan 1944.
If you put your finger gently on a loudspeaker you will feel it vibrate - if it is playing a low note loudly you can see it moving. When it moves forwards, it compresses the air next to it, which raises its pressure. Some of this air flows outwards, compressing the next layer of air. The disturbance in the air spreads out as a travelling sound wave. Ultimately this sound wave causes a very tiny vibration in your eardrum - but that's another story.
waves were reflected back to the transducer as they crossed interfaces of different acoustic impedance. More simply, the ultrasound bounced off the
Unless you travel into the vacuum of space, sound is all around you every day.. You hear sounds; you don't touch them. But as the vibrations that sound creates in other objects. The idea that something so intangible can lift objects can seem unbelievable, but it's a real phenomenon.
Archaeology is a continuously evolving field where there is a constant stream of new branches and excavation methods. Due to the influx of new technologies and innovations in recent decades, archaeologists have been able to excavate previously inaccessible areas. For example, new diving equipment and tools such as proton magnetometers, side-scan sonar, sub-bottom profiler, and miniature submarines have allowed archaeologists to dive into the deep depths of the ocean. As a result, the branch of underwater archaeology was created to search for shipwrecks and other artifacts on the ocean floor. Underwater archaeology’s role has increased in recent years as it allows archaeologists to more accurately interpret the past by supplementing information gained through traditional land excavations.
Sound is defined as areas of high and low pressure that move outward to form a longitudinal wave. The amplitude and pitch of the sound is dependent on the source and amount of energy produced. Sound is produced by vibrating objects, the vibrations cause disturbances in the surrounding air molecules. When the vibrating object moves outward it causes the air molecules around it to compress and create a high pressure region. As the object moves inward the air molecules expand and create a low pressure region. The high pressure regions are called compressions and the low pressure regions rarefactions. The equation of sound waves is speed = wavelength x frequency or v = f x .
Most people have some sort of familiarity with submarine crafts; most of which are most likely related to the navy. This is a very accurate depiction of submarines, as they are primarily used for this, however, they are used in areas of scientific research as well. The purpose of this web page is to go into the history of the submarine to see how it has developed over time. We will also look at how a submarine works, from a physics standpoint.
The carbon transmitter uses carbon granules between metal plates called, electrodes, with one consisting of a thin diaphragm that moves by pressure from sound waves and transmits them to the carbon granules. These electrodes conduct electricity flowing through the carbon. The sound waves hit the diaphragm, causing the electrical resistance of the carbon to vary. The electronic transmitter is composed of a thin disk of metal-coated plastic held above a thick, hollow metal disk. This plastic disk is electrically charged, and creates an electric field.
The term radar actually comes from the acronym representing Radio Detection And Ranging. Radar is a detection system used to locate and identify objects. Simply put, radar is the process in which radio waves are emitted from the source of the system; those waves ricochet off objects in their path, and the radar system detects the echoes of signals that return. “One would think that so important a contribution to the world’s technology would be chronicled with great care at every step. This, unfortunately, is not the case, and for reasons quite understandable” (Page 14). Sometimes history can be hard to distinguish between truth and legend, and the history of radar is no exception.
Acoustics is a science that deals with the study of sound. It is known to be one of the branches of physics; studying oscillations and sound waves from the lowest to high frequencies. Acoustics is known to be one of the oldest sciences, and dates back to ancient times as people had the need to understand the nature of speech and hearing. The main reason acoustics was discovered and is one of the oldest sciences is because of the need for the knowledge of the sounds of music and musical instruments. Pythagoras, an ancient mathematician, was the first person to ever find out that tone height corresponds to the length of the sting or tube. While Aristotle, Pythagoras apprentice at the time, helped more to explain that an echo is created as the sound reflection from obstacles.
3. Brain, Marshall, and Tom Harris. "How GPS Receivers Work." 25 September 2006. HowStuffWorks.com. 01 June 2010.
An acoustic wave can simply be described as a longitudinal wave. A longitudinal wave is a wave that vibrates and moves in the direction of its propagation. This means the medium is either in the same or opposite direction of the way the wave travels. Acoustic waves are a form of Mechanical longitudinal waves; these waves are otherwise known as compression waves or compressional waves. Compressional waves obviously produce compression, decompression, and rarefaction to travel.