How is depth measured? Great encyclopedia of oil and gas
World Ocean- a global connected body of sea water surrounding continents and islands. Almost three-quarters (71%) of the Earth's surface is covered by the world's oceans.
What are the oceans?
Continents and huge archipelagos divide the world's oceans into 5 huge parts (oceans):
The smallest regions of the oceans are known as seas, gulfs, straits, etc. The doctrine of earth's oceans called oceanology.
How is ocean depth measured?
Scientists who study the sea are called oceanographers. Since the depths of the ocean are dark
cold, scientists don’t know much about them. Some parts ocean floor were studied only through the windows of research submarines and through the eyepieces of bathyscaphes made specifically for exploring the depths of the sea, but still this material is obviously not enough.
One of the problems that oceanographers are interested in is the depth of the ocean. Measuring it is called “listening to depth.” In the old days, measurements were made using a rope with a weight attached to it, which was lowered into the water. Later, they began to use very narrow wire for this, the same type from which piano strings are made.
These days, scientists can get an even clearer picture of the depth of the ocean floor with the help of an invention called an echo sounder. It uses echo to study the ocean floor.
The device installed on board the ship sends sound signal. Sound travels through water at a speed of about one mile per second. It is reflected from the bottom and caught on the return path by a special device. The deeper the water, the longer it takes for the echo to reach the side of the ship.
A modern echo sounder sends ultra to the bottom sound waves. Later, instruments record the echo as a dark stripe on a sheet of special paper. Usually this paper contains a decoding of these symbols in fathoms (a fathom is equal to 1.8 meters).
Using an echo sounder, you can simply find the depth of the sea. However, the device is able to do not only this. He can draw a line in detail seabed under the ship, in which case listen to the bottom every few meters along the ship.
In this case, the ship passes over the submarine, the echo sounder registers its exact shape. In this case, the bottom is level, the echo sounder will depict it the same way. The echo sounder will not miss even a small convexity of the bottom less than a meter high!
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You need to know the solution and answer to the question The depth of the ocean can be measured using what? and execute correctly homework in the subject Geography? Ready solution see below.
The depth of the ocean can be measured using what?
The world ocean is a global connected body of sea water surrounding continents and islands. Almost three-quarters (71%) of the Earth's surface is covered by the world's oceans.
Scientists who study the sea are called oceanographers. Because the depths of the ocean are dark and cold, scientists don't know much about them. Some parts of the ocean floor have been studied only through the windows of research submarines and through the eyepieces of bathyscaphes made specifically for studying the depths of the sea, but still this information is clearly not enough.
One of the problems of interest to oceanographers is the depth of the ocean. Measuring it is called “listening to depth.” In the old days, measurements were made using a rope with a weight attached to it, which was lowered into the water. Later, they began to use very thin wire for this, like the one from which piano strings are made.
These days, scientists can get a much more accurate picture of the depth of the ocean floor with the help of one invention called an echo sounder. It uses echoes to probe the ocean floor.
A device installed on board the ship sends a sound signal. Sound travels through water at a speed of about one mile per second. It is reflected from the bottom and caught on the way back by a special device. The deeper the water, the longer it takes for the echo to reach the side of the ship.
A modern echo sounder sends ultrasonic waves to the bottom. Then the instruments register the echo in the form of a black line on a sheet of special paper. Usually this paper contains the decoding of these signs in fathoms (a fathom is equal to 1.8 meters).
Echo sounder – technical device, which is based on the use of watches to measure the depth of the ocean. This sonar principle.
Before the invention of the echo sounder, shallow depths up to 4 m were measured with a foot rod, i.e. pole, marked in feet, and large ones up to 500 m - in lot, i.e. a weight attached to a long cable.
Sent from the surface of the ocean into the depths sound pulse and the echo reflected from the ocean floor is received. The clock measures time interval from the sending of the impulse to the return of the echo. The depth is determined by the echo delay:
where v is the speed of sound in sea water, t is the delay time, and the two in the denominator takes into account the round trip path traveled by the signal.
The accuracy of measurements depends on how accurately the speed of sound waves in water is known and how accurately the signal delay is measured
A regular stopwatch allows you to measure time with precision up to tenths of a second(i.e. depth accurate to hundreds of meters). For greater accuracy, electronic stopwatches are used.
Source: based on materials from P. Makovetsky’s book “Look at the Root”
Did you know?
Is the thunderstorm far away?
If you measure the time that elapses between the flash of lightning and the clap of thunder, you can determine the distance at which the thunderstorm is located.
The speed of sound is approximately 360 meters per second. By multiplying time by the speed of sound, you can determine the distance to the thunderstorm (since the speed of light is much higher than the speed of sound, it can be neglected).
Typically, thunder can be heard at a distance of up to 15-20 kilometers, so if an observer sees lightning but does not hear thunder, then the thunderstorm is more than 20 kilometers away.
Venus on the face of the Sun
“I say: I saw Venus like a mole on the face of the Sun.”
These lines are written on parchment that is over a thousand years old! The author is an encyclopedist scientist Ancient East al-Farabi.
Was the medieval astronomer wrong? After all, in order to see the passage of Venus across the disk of the Sun, he first needed to high accuracy calculate the movement of the planets, determine the day and hour of the eclipse.
Calculations by modern experts have shown that in 910 AD, from the territory of modern Kazakhstan, it was indeed possible to observe a “mole on the face of the Sun.”
The sky is in diamonds
This expression comes to mind when you read the message that the production of integrated circuits has recently been launched, in which sapphire crystals are used instead of a semiconductor substrate.
![](https://i2.wp.com/class-fizika.ru/images/yut/112.jpg)
Such microcircuits are many times more expensive than traditional ones. But it is also many times more reliable in space, where failure of any microcircuit can lead to death spacecraft: crystals gemstone, as studies have shown, have special anti-radiation properties that protect microcircuits from cosmic rays.
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Measuring the sea depth under the keel of a vessel is especially important when sailing in shallow water areas, as well as when passing through narrow areas. Using an echo sounder, the topography of the bottom of water basins can be determined.
When measuring the depth of the sea with an echo sounder, it turned out that the moments of departure and reception of the ultrasound were separated by a time interval of 0 6 s.
When measuring the depth of the sea under the ship using an echo sounder, it turned out that the moments of departure and reception of sound were separated by a time interval of 0 8 seconds.
The echo phenomenon is also used to measure the depths of seas and oceans. For this there are special devices- echo sounders.
The echo phenomenon is also used to measure the depths of seas and oceans. There are special echo sounders for this purpose. The emitter is turned on for very short periods of time. The pulse of ultrasonic frequency waves excited by it penetrates the water column and, reflected from the bottom, returns to the receiving device. The speed of propagation of ultrasonic waves in water is known: it is equal to 1450 m/s, almost 5 times more than in air.
An echo sounder is a device designed to measure the depths of a sea or river. The echo sounder emitter is installed on the bottom of the ship so that the beam of ultrasonic waves is directed vertically downward. It emits ultrasonic waves in separate short-term pulses, which, due to their high frequency, contain a large number of waves Having reached the bottom, the pulse is reflected from it in the form of an echo and arrives at the receiver located next to the emitter. The recording device records on a special tape the moment the pulse was sent and the moment it returned. Knowing the speed of propagation of ultrasound in water, the depth of the sea under the ship is determined from these marks.
Ultrasounds were first practically used in echo sounders to measure sea depth. Reflecting from the bottom of the sea, the ultrasounds reach the receiver after some time. Based on the time interval that elapsed between the sending of the signal and its return, knowing the speed of propagation of ultrasound, the distance to the bottom of the sea is determined.
Ultrasounds were first practically used in echo sounders to measure sea depth.
Most typical example Acoustic location can be used to measure sea depth using ultrasonic echo sounders. Therefore, this method can measure both fairly large (several kilometers) and very small (several millimeters) distances. The principle of using this method is as follows. At the moment the cam closes 2 contacts K.
However, using this principle to obtain sufficiently accurate and reliable measurements of sea depth for a long time it didn't work out. The reason for this is that when an explosion occurs, spherical sound waves travel from the source. If the bottom topography is uneven, as can be seen from Fig. 212, the first reflected signal may not come from areas of the bottom directly below the ship, but from areas closer to the ship, but located on the side. Therefore, with a non-directional sound wave emitter, big mistakes in determining depth.
Hydroacoustic equipment, which, in connection with the development of acoustic underwater communication technology, sea depth measurement, sonar and noise direction finding, also represents a specific group of electroacoustic devices. Closely adjacent to them are seismoacoustic instruments and geophones, which are used for seismic exploration, prevention of collapses in mine workings and for monitoring earthquakes.
It would seem that valuable results for the purposes of seismic sounding of the surface layers of the earth can be obtained by using the pulse method, similar to what is done in hydroacoustics when measuring the depth of the sea with echo sounders. To do this, one could use sound or ultrasonic frequencies elastic waves, sending them by some emitter into the earth and receiving reflections. However, in practice this cannot be done, and if it is possible, then only for very small distances. In addition, due to the heterogeneous structure of the surface layers of the earth - cracks and various kinds inclusions in the soil - sound waves are partially scattered and partially change the direction of their propagation. Therefore, until now the main source of elastic waves has been an explosion.
It should be noted that the study and attempts to use elastic vibrations and waves with frequencies of 15 - 20 kHz or more, called ultrasound (since they are not detected by the human ear), were made back in the 19th century. Lan-Gevin successfully used ultrasonic vibrations to measure sea depths, detect boats and other scientific and practical purposes. Search practical application Ultrasounds intensified greatly in the 20s. At this time in the Soviet Union it was proposed to use ultrasound to detect cavities, cracks and other defects and solids without destroying them.
Classification of lots. Navigation practice confirms the urgent need to have instruments on board the vessel that are always ready for action, allowing them to measure depths and take soil samples. Thus, careful measurement of depths at certain intervals makes it possible to thoroughly check the ship’s position in the fog and safely approach the anchorage. Depths at sea are measured with special instruments - lots.
Depending on the measured depth, lots are divided into deep-water and navigational. Navigation ones are intended for measuring relatively shallow depths. Everyone is supplied with them sea vessels to ensure navigation safety. The design of navigation lots makes it possible to measure depths while the vessel is moving with sufficient accuracy for navigation.
Rice. 16.
Based on the principle of operation and design, navigation lots are divided into manual, mechanical and hydroacoustic.
Hand lot. The main parts of a hand lot are lead (or cast iron) weight 1 and lotline 2 (Fig. 16). The weight has the shape of a truncated pyramid or cone, about 30 cm high and weighing from 3 to 5 kg. The upper part of the weight ends in an eyelet with a strap made of steel cable sheathed in leather threaded into it. A recess is made in the lower, wider part of the weight, into which a mixture of lard and crushed chalk is smeared before measuring the depth. When the weight is lowered to the bottom, soil particles stick to the putty. This allows you to determine the nature of the soil after the lot is lifted onto the deck. The weight is connected to a lotline, which is made from a line more than 50 m long and about 25 mm thick. Before breaking (marking), the lotline is pulled out well. When setting out, the place where the line and the weight connect is taken as zero, since when measuring the depth of the sea it usually rests on the ground. At a distance of 2-3 m from the weight, a brake-peg made of hard wood is thrown into the lotline, and then every 10 m - flags (multi-colored pieces of material) with the following sequence of colors: red - 10 m, blue - 20 m, white - 30 m , yellow - 40 m, white-red - 50 m. Each ten-meter section is divided in half with a leather mark with “hatchets”. A mark with one “hatchet” is inserted at the 5 m mark, with two – 15 m, etc. Each five-meter section is divided into five equal parts with leather marks in the form of teeth: a mark with one tooth is inserted in places corresponding to 1; 6; eleven; 16; 21; 26; 31 and 46 m; brand with two teeth - by 2; 7; 12; 17; 22; 27; 32; 37; 42 and 47 m, etc. Sometimes meter-long sections of the lotline are broken up into smaller divisions by small leather marks (for boat measurements).
The lotline is thrown from the windward side so that the lotline does not fall under the hull of the ship. A hand lot is used only at a vessel speed of up to 5 knots and a sea depth of no more than 50 m. At depths of up to 150 m, a diplot is used, the design of which is similar to that of a hand lot. You can only measure depths with a diplot while parked.
The hand lot and diplot are used not only for measuring depth. They determine the drift of a ship at anchor, the height of the tide at the anchorage site, etc.
Mechanical lot. The action of the mechanical lot (Fig. 17, a) is based on the principle hydrostatic pressure. The main parts of the mechanical lot are a bathometric tube, a weight 1 and a winch (Fig. 17, b) with a lotline 3, equipped with an automatic brake that is activated the moment the weight touches the ground. Using a weight, a copper pencil case 2 with a glass tube inserted into it (see Fig. 17, a), sealed at one end, is immersed in the sea.
Rice. 17.
As you dive, the air contained in the tube is compressed under the pressure of the water filling it. The immersion depth of the tube is determined by the formula
where h is the height of water rise in the tube;
P0 -Atmosphere pressure air on the surface of the water;
B is the weight of a unit volume of sea water;
L is the length of the tube.
The inner walls of the tube are coated with a special paint that is washable sea water. This makes it easy to determine the value of h. Lot tubes have standard sizes. Therefore, the depth is determined using a special scale calculated according to formula (18). By placing the tube on scale 4, the depth is determined by a reading that coincides with the boundary of the washed-off paint in the tube.
The disadvantage of a mechanical lot is the labor-intensive process of measuring depth and the possibility of use only at a vessel speed of up to 12 knots.
Hydroacoustic lot. Hydroacoustic surveys measure depths up to 2000 m at unlimited vessel speed. The lot's special instruments - recorders - provide a visual representation of the topography of the seabed. The great advantages of hydroacoustic lots contributed to their widespread on sea vessels.
A detailed description of the principle of operation, design and operating rules of hydroacoustic lots is given in the fourth section of this textbook.