What is the phenomenon of tides. Completed. Tides in the Earth's air shell and in its solid
The ebb and flow is the periodical rise and fall of the water level in the oceans and seas.
Twice a day, with an interval of about 12 hours and 25 minutes, the water near the ocean or open sea rises and, if there are no obstacles, sometimes floods large areas - this is the tide. Then the water lowers and recedes, exposing the bottom - this is an ebb tide. Why is this happening? Even ancient people thought about this, they noticed that these phenomena are associated with the Moon. I. Newton was the first to point out the main cause of the ebb and flow - this is the attraction of the Earth by the Moon, or rather, the difference between the attraction by the Moon of the entire Earth as a whole and its water shell.
Explaining the ebb and flow of Newton's theory
The attraction of the Earth by the Moon consists of the attraction by the Moon of individual particles of the Earth. Particles in this moment closer to the moon, they are attracted by it more strongly, and more distant ones are weaker. If the Earth were absolutely solid, then this difference in the force of gravity would not play any role. But the Earth is not an absolutely rigid body, therefore, the difference in the forces of attraction of particles located near the surface of the Earth and near its center (this difference is called the tidal force) displaces the particles relative to each other, and the Earth, primarily its water shell, is deformed.
As a result, water rises on the side facing the Moon and on its opposite side, forming tidal ridges, and excess water accumulates there. Due to this, the water level in other opposite points of the Earth decreases at this time - an ebb tide occurs here.
If the Earth did not rotate, and the Moon remained motionless, then the Earth, together with its water shell, would always retain the same elongated shape. But the Earth rotates and the Moon moves around the Earth in about 24 hours and 50 minutes. With the same period, the tidal ledges follow the Moon and move along the surface of the oceans and seas from east to west. Since there are two such protrusions, a tidal wave passes over each point in the ocean twice a day with an interval of about 12 hours and 25 minutes.
Why the height of the tidal wave is different
In the open ocean, the water rises slightly when a tidal wave passes: about 1 m or less, which remains practically invisible to sailors. But off the coast, even such a rise in the water level is noticeable. In bays and narrow bays, the water level rises much higher during high tides, since the coast prevents the movement of the tidal wave and water accumulates here during the entire time between ebb and flow.
The largest tide (about 18 m) is observed in one of the bays on the coast in Canada. In Russia, the largest tides (13 m) occur in the Gizhiginsky and Penzhinsky bays of the Sea of Okhotsk. In inland seas (for example, in the Baltic or the Black), the ebb and flow are almost imperceptible, because masses of water do not have time to penetrate into such seas, moving along with the ocean tidal wave. But all the same, in each sea or even lake there are independent tidal waves with a small amount of water. For example, the height of the tides in the Black Sea reaches only 10 cm.
In the same area, the tide height is different, since the distance from the Moon to the Earth and the maximum height of the Moon above the horizon change over time, and this leads to a change in the magnitude of the tidal forces.
Tides and Sun
The sun also has an effect on the tides. But the tidal forces of the Sun are 2.2 times less than the tidal forces of the Moon.
During the new moon and full moon, the tidal forces of the Sun and Moon act in the same direction - then the highest tides are obtained. But during the first and third quarters of the Moon, the tidal forces of the Sun and the Moon oppose, so the tides are smaller.
Tides in the Earth's air shell and in its solid
Tidal phenomena occur not only in the water, but also in the air shell of the Earth. These are called atmospheric ebbs and flows. Tides also occur in the solid of the Earth, since the Earth is not absolutely solid. Vertical oscillations of the Earth's surface due to tides reach several tens of centimeters.
Practical use of the ebb and flow
A tidal power plant is a special type of hydroelectric power plant that uses the energy of tides, and in fact the kinetic energy of the Earth's rotation. Tidal power plants are built on the shores of the seas, where the gravitational forces of the Moon and the Sun change the water level twice a day. Fluctuations in the water level near the coast can reach 18 meters.
In 1967, a tidal power plant was built in France at the mouth of the Rance River.
An experimental TES has been operating in Russia since 1968 in Kislaya Bay on the coast of the Barents Sea.
There are PESs and abroad - in France, Great Britain, Canada, China, India, USA and other countries.
© Vladimir Kalanov,
"Knowledge is power".
The phenomenon of tides at sea has been noticed since ancient times. Herodotus wrote about tides as early as the 5th century BC. For a long time people could not understand the nature of the tides. Various fantastic assumptions have been made, such as that the Earth breathes. Even the famous scientist (1571-1630), who discovered the laws of planetary motion, considered the ebb and flow as a result ... of the respiration of the planet Earth.
The French mathematician and philosopher (1596-1650) was the first among European scientists to point out the connection between tides and, but did not understand what this connection was. Therefore, he gave such a far from the truth explanation of the tide phenomenon: the Moon, revolving around the Earth, presses on the water, forcing it to go down.
Gradually, scientists figured out this, I must say, difficult problem, and it was found that tides are a consequence of the influence of the gravitational forces of the Moon and (to a lesser extent) the Sun on the surface of the ocean.
In oceanology it is given following definition: rhythmic rises and falls of waters, as well as their accompanying currents, are called ebb and flow.
High and low tides occur not only in the ocean, but also in the atmosphere and the earth's crust. The uplift of the earth's crust is very insignificant, so they can only be determined with special instruments. Another thing is the water surface. Particles of water move, and, receiving acceleration from the moon, approach it incomparably more than the earth. Therefore, on the side facing the moon, the water rises up, forming a bend, a kind of water hump on the surface of the ocean. As the Earth rotates on its axis, this ridge of water moves along the surface of the ocean following.
In theory, even distant stars are involved in the formation of tides. But this remains a purely theoretical premise, since the effect of the stars is negligible and can be neglected. More precisely, even, it cannot be neglected, since there is nothing to neglect. The influence of the Sun on the ocean surface is 3-4 times weaker than the influence of the Moon due to the great distance of the star. Powerful lunar tides mask the Sun's gravitational pull, so there are no solar tides as such.
The extreme position of the water level at the end of the tide is called full of water, and at the end of low tide - low water.
Two photographs taken from the same point at moments of low and high water,
give an idea of tidal level fluctuations.
If we start observing the tide at the time of high water, then we will see that in 6 hours the lowest water level will come. After that, the tide will begin again, which will also continue for 6 hours until the highest level is reached. The next high tide will come 24 hours after the start of our observation.
But this will only happen in the case of ideal, theoretical conditions. In reality, during the day there is one full and one low water - and then the tide is called daily. Or it can happen in two tidal cycles. In this case, we are talking about a semi-daily tide.
The period of daily tide does not last 24 hours, but 50 minutes longer. Accordingly, the semi-daily tide lasts 12 hours and 25 minutes.
The world's oceans are dominated by semi-diurnal tides. This is declared by the rotation of the Earth around its axis. The tide, like a huge gentle wave length of many hundreds of kilometers, spreads over the entire surface of the World Ocean. The period of occurrence of such a wave fluctuates in each place of the ocean from half a day to a day. On the basis of the frequency of the onset of tides, they are distinguished as daily and semi-daily.
During a complete revolution of the Earth around its axis, the Moon moves about 13 degrees across the sky. To "catch up" with the Moon, the tidal wave just takes 50 minutes. This means that the time of arrival of full water in the same place in the ocean is constantly shifting relative to the time of day. So, if today there was full water at noon, then tomorrow it will be at 12 hours 50 minutes, and the day after tomorrow - at 13 hours 40 minutes.
In the open ocean, where the tidal wave does not meet resistance from the continents, islands, uneven bottom and coastline, there are mostly regular semi-daily tides. Tidal waves in the open ocean are invisible, where their height does not exceed one meter.
In full force, the tide manifests itself on the open coast of the ocean, where for tens and hundreds of miles, no islands or sharp bends of the coastline are visible.
When the Sun and the Moon are located on the same line on one side of the Earth, the force of attraction of both luminaries adds up, as it were. This happens twice during a lunar month - on a new moon or a full moon. This position of the luminaries is called syzygy, and the tide that comes on these days is called. Syzygy tides are the highest and most powerful tides. In contrast, the lowest tides are called.
It should be noted that the level of syzygy tides in the same place is not always the same. The reason is the same: the movement of the Moon around - the Earth and the Earth - around the Sun. Let's not forget that the Moon's orbit around the Earth is not a circle, but an ellipse, which creates a rather tangible difference between the perigee and apogee of the Moon - 42 thousand km. If during syzygy the Moon is at perigee, that is, at the smallest distance from the Earth, then this will cause a high tidal wave. Well, if during the same period the Earth, moving in its elliptical orbit around the Sun, is at the smallest distance from it (and also coincidences occasionally occur), then the ebb and flow will reach the maximum value.
Here are some examples showing the maximum heights that ocean tides reach at specific locations in the world (in meters):
Name |
Location |
High tide (m) |
Mezen Bay of the White Sea | ||
Colorado river estuary | ||
Penzhinskaya Bay of the Sea of Okhotsk | ||
Seoul River Mouth | South Korea | |
Mouth of the Fitzroy River | Australia | |
Grenville | ||
Mouth of the Coxoak River | ||
Port of Gallegas | Argentina | |
Bay of Fundy |
Water rises at different rates during high tide. The nature of the tide is highly dependent on the angle of inclination of the seabed. At steep banks, the water rises slowly at first - 8-10 millimeters per minute. Then the tide speed increases, becoming the highest towards the half-water position. Then it slows down to the position of the upper tide limit. The dynamics of the ebb tide is similar to the dynamics of the tide. But the tide looks quite different on wide beaches. Here the water level rises very quickly and is sometimes accompanied by a high tidal wave that rushes rapidly along the shallows. Those who gape on such beaches shouldn't expect anything good in these cases. The sea element does not know how to joke.
In the inland seas, fenced off from the rest of the ocean by narrow and shallow winding straits or clusters of small islands, tides come with barely noticeable amplitudes. We see this in the example of the Baltic Sea, reliably closed from the tides by shallow Danish straits. The theoretical height of the tide in the Baltic Sea is 10 centimeters. But these tides are invisible to the eye, they are hidden by fluctuations in the water level from the wind or from changes in atmospheric pressure.
It is known that in St. Petersburg there are frequent floods, sometimes very strong. Let us remember how vividly and truthfully he conveyed the drama of the strongest flood of 1824 in the poem “ Bronze Horseman"The great Russian poet A.S. Pushkin. Fortunately, floods of such force in St. Petersburg have nothing to do with the tides. These floods are caused by the winds of cyclones, which significantly raise the water level by 4–5 meters in the eastern part of the Gulf of Finland and in the Neva.
The ocean tides are even less affected by the inland seas of the Black and Azov, as well as the Aegean and Mediterranean. In the Sea of Azov, connected to the Black Sea by the narrow Kerch Strait, the amplitude of the tides is close to zero. In the Black Sea, fluctuations in water level under the influence of tides do not even reach 10 centimeters.
Conversely, in bays and narrow bays that have free communication with the ocean, the tides reach significant levels. Freely entering the bay, tidal masses rush forward, and, finding no way out among the narrowing shores, rise up and flood the land over a large area.
During ocean tides, a dangerous phenomenon is observed in the estuaries of some rivers, called boron... Flow sea water, entering the riverbed and meeting the river stream, forms a powerful foamy shaft, rising up as a wall and rapidly moving against the river flow. On its way, the forest erodes the banks and can destroy and sink any ship if it is in the channel of the river.
On the greatest river South America In the Amazon, a powerful tidal wave 5-6 meters high travels at a speed of 40-45 km / h for a distance of up to one and a half thousand kilometers from the mouth.
Sometimes tidal waves stop the flow of rivers and even turn it in the opposite direction.
On the territory of Russia, small in height boron is experienced by the rivers flowing into the Mezen Bay of the White Sea.
In order to use the energy of tides in some countries, including Russia, tidal power plants have been built. The first tidal power plant, built in the Kislogubskaya Bay of the White Sea, had a capacity of only 800 kilowatts. Subsequently, TPPs were designed with a capacity of tens and hundreds of thousands of kilowatts. This means that hot flashes begin to work for the benefit of the person.
And last, but globally important about the tides. Tidal currents meet resistance from continents, islands and the seabed. Some scientists believe that as a result of the friction of water masses against these obstacles, the rotation of the Earth around its axis slows down. At first glance, this slowdown is quite insignificant. Calculations have shown that over the entire time of our era, that is, over 2000 years, the day on Earth became 0.035 seconds longer. But what was the calculation based on?
It turns out that there is evidence, albeit indirect, that the rotation of our planet is slowing down. Studying the extinct corals of the Devonian period, the English scientist D. Wells found that the number of diurnal growth rings is 400 times more than the annual ones. In astronomy, the theory of stability of planetary movements is recognized, according to which the length of the year remains practically unchanged.
It turns out that in the Devonian period, that is, 380 million years ago, a year consisted of 400 days. Consequently, the day then had a duration of 21 hours 42 minutes.
If D. Wells was not mistaken when calculating the daily rings of ancient corals, and if the rest of the calculations are correct, then everything goes to the fact that even some 12-13 billion years will not pass, as the earth's day will become equal in length to the lunar month. And then what? Then our Earth will be constantly facing one side of the Moon, as is currently the case with the Moon in relation to the Earth. The rise in water will stabilize on one side of the Earth, the tides will cease to exist, and the solar tides are too weak to be felt.
We provide an opportunity for our readers to independently assess this rather exotic hypothesis.
© Vladimir Kalanov,
"Knowledge is power"
Our planet is constantly in the gravitational field, which is created by the Moon and the Sun. This is the cause of a unique phenomenon, expressed in the ebb and flow of the earth. Let's try to figure out whether these processes affect the environment and human life.
The mechanism of the phenomenon "ebb and flow"
The nature of the formation of ebb and flow has already been sufficiently studied. Over the years, scientists have investigated the causes and results of this phenomenon.
Such fluctuations in the water level can be shown in the following system:
- The water level gradually rises, reaching its highest point. This phenomenon is called full water.
- After a certain period of time, the water begins to subside. Scientists have defined this process as "ebb".
- For about six hours, the water continues to drain to its minimum point. This change was named in the form of the term "low water".
You can see some pattern if you observe the tide process in the same place for a month. The results of the analysis are interesting: daily low and high water changes its location. With such a natural factor as the formation of a new moon and a full moon, the levels of the studied objects move away from each other.
Consequently, this makes the tide amplitude at its maximum twice a month. The appearance of the smallest amplitude also occurs periodically, when, after the characteristic influence of the Moon, the levels of small and full waters gradually approach each other.
The causes of ebb and flow on Earth
There are two factors that influence the formation of ebb and flow. It is necessary to carefully consider both objects that affect the change in the water space of the Earth.
Impact of lunar energy on ebb and flow
Although the influence of the Sun on the cause of the ebb and flow is undeniable, but still greatest value in this matter belongs to the effects of lunar activity. In order to feel the significant influence of the satellite's gravity on our planet, it is necessary to trace the difference in the attraction of the Moon in different regions of the Earth.
The experimental results will show that the difference in their parameters is rather small. The thing is that the point on the earth's surface closest to the Moon is literally 6% more exposed to external influence than the most distant one. It is safe to say that this separation of forces pushes the Earth apart in the direction of the Moon-Earth trajectory.
Taking into account the fact that our planet constantly turns around its axis during the day, a double tidal wave passes twice along the perimeter of the created extension. This is accompanied by the creation of the so-called double "valleys", the height of which, in principle, does not exceed 2 meters in the oceans.
On the territory of the earth's land, such fluctuations reach a maximum of 40-43 centimeters, which in most cases remains unnoticed by the inhabitants of our planet.
All this leads to the fact that we do not feel the force of the ebb and flow either on land or in the water element. You can observe a similar phenomenon on a narrow strip of the coastline, because the waters of the ocean or sea, by inertia, sometimes gain impressive height.
From all that has been said, we can conclude that the ebb and flow are most associated with the Moon. This makes research in this area the most interesting and relevant.
Influence of solar activity on ebb and flow
Significant remoteness of the main star Solar system from our planet affects the fact that its gravitational effect is less noticeable. As a source of energy, the Sun is certainly much more massive than the Moon, but still makes itself felt by the impressive distance between two celestial objects. The amplitude of solar tides is almost half that of the tidal processes of the Earth's satellite.
It is a well-known fact that during the full moon and the growth of the moon, all three celestial bodies - the Earth, the Moon and the Sun - are located on one straight line. This leads to the folding of the lunar and solar tides.
During the period of direction from our planet to its satellite and the main star of the Solar System, which differs from each other by 90 degrees, there is some influence of the Sun on the process under study. There is an increase in the level of low tide and a decrease in the level of high tide of the earth's waters.
All indications are that solar activity also affects the energy of the ebb and flow on the surface of our planet.
The main types of ebb and flow
You can classify a similar concept according to the duration of the ebb and flow cycle. The disengagement will be fixed using the following items:
- Semi-daily changes in the surface of the water space... Such transformations consist in two full and the same amount of incomplete waters. The parameters of the alternating amplitudes are practically equal to each other and look like a sinusoidal curve. Most of all, they are localized in the waters of the Barents Sea, on the vast line of the coastal strip of the White Sea and on the territory of almost the entire Atlantic Ocean.
- Daily fluctuations in water level... Their process consists in one full and incomplete water for a period calculated within a day. A similar phenomenon is observed in the area The Pacific, and its formation is extremely rare. During the period of the passage of the Earth's satellite through the equatorial zone, the effect of standing water is possible. If the Moon tilts with the smallest index, small tides of an equatorial nature occur. At the highest numbers, the process of formation of tropical tides occurs, accompanied by the greatest power of water inflow.
- Mixed tides... This concept includes the presence of semi-diurnal and diurnal tides of irregular configuration. The semi-diurnal changes in the level of the earth's water envelope, which have an irregular configuration, are similar in many ways to semi-diurnal tides. In altered diurnal tides, a tendency towards diurnal fluctuations can be observed, depending on the degree of declination of the moon. The most prone to mixed tides are the waters of the Pacific Ocean.
- Abnormal hot flashes... These rises and falls of water do not fit the description of some of the signs listed above. This anomaly is associated with the concept of "shallow water", which changes the cycle of rise and fall of the water level. The influence of this process is especially pronounced in river estuaries, where the tides are shorter in time than the ebb tides. You can observe a similar cataclysm in some parts of the English Channel and in the currents of the White Sea.
Earth's ebb and flow chart
There is a so-called ebb and flow table. It is necessary for people who depend on the nature of their activities on changes in the earth's water level. To have accurate information on this phenomenon, you need to pay attention to:
- Designation of an area where it is important to know the data on the ebb and flow of the tide. It is worth remembering that even closely spaced objects will have different characteristics of the phenomenon of interest.
- Finding the necessary information using Internet resources. For more accurate information, you can visit the port of the region under study.
- Specifying the time needed for accurate data. This aspect depends on whether the information is needed for a specific day or the study schedule is more flexible.
- Working with the table in the mode of emerging needs. It will display all the tide information.
- The columns at the top of the table indicate the days and dates of the alleged event. This item will allow you to find out the point of determining the time frame of the studied.
- Under the line of temporary accounting there are numbers placed in two rows. In the format of the day, the decoding of the phases of the rising of the moon and the sun is placed here.
- Below is a waveform chart. These indicators record the peaks (tides) and troughs (ebbs) of the waters of the study area.
- After calculating the amplitude of the waves, the data of the arrival of celestial bodies are located, which affect the changes in the water shell of the Earth. This aspect will allow observing the activity of the Moon and the Sun.
- On both sides of the table, you can see numbers with plus and minus indicators. This analysis is important for determining the level of rise or fall of water, measured in meters.
All these indicators cannot guarantee one hundred percent information, because nature itself dictates to us the parameters by which its structural changes occur.
The impact of ebb and flow on the environment and humans
There are many factors of the influence of ebb and flow on human life and the environment. Among them there are phenomenal discoveries that require careful study.
Killer waves: hypotheses and consequences of the phenomenon
This phenomenon causes a lot of controversy among people who trust only unconditional facts. The fact is that wandering waves do not fit into any system of the occurrence of this phenomenon.
The study of this object became possible using radar satellites. These designs made it possible to record a dozen ultra-large amplitude waves over a period of a couple of weeks. The size of such a rise of the water block is about 25 meters, which indicates the grandeur of the phenomenon under study.
Killer waves directly affect human life, because over the past decades, such anomalies have carried huge vessels such as supertankers and container ships into the ocean depths. The nature of the formation of this stunning paradox is unknown: giant waves form instantly and just as quickly disappear.
There are many hypotheses regarding the reason for the formation of such a whim of nature, but the appearance of eddies (single waves due to the collision of two solitons) is possible with the interference of the activity of the Sun and the Moon. This issue is still becoming a reason for discussions among scientists specializing in this topic.
The effect of ebb and flow on organisms that inhabit the Earth
The ebb and flow of the ocean and sea especially affects marine life. This phenomenon exerts the greatest pressure on the inhabitants of coastal waters. Due to this change in the level of the earth's water, sedentary organisms develop.
These include molluscs, which have perfectly adapted to the vibrations of the Earth's liquid shell. Oysters at the highest tides begin to multiply actively, which indicates that they respond favorably to such changes in the structure of the water element.
But not all organisms respond so favorably to external changes. Many species of living things suffer from periodic fluctuations in water levels.
Although nature takes its toll and coordinates changes in the overall balance of the planet, biological substances adapt to the conditions presented to them by the activity of the Moon and the Sun.
The impact of ebb and flow on human life
This phenomenon affects the general state of a person more than the phases of the moon, to which the human body may be immune. However, the most ebbs and flows affect the production activities of the inhabitants of our planet. It is unrealistic to influence the structure and energy of the ebb and flow of the sea, as well as the oceanic sphere, because their nature depends on the gravity of the Sun and the Moon.
Basically, this cyclical phenomenon only brings destruction and trouble. Modern technologies allow this negative factor to be directed in a positive direction.
An example of such innovative solutions are pools that trap such fluctuations in water balance. They must be built in a way that the project is cost-effective and practical.
To do this, it is necessary to create such pools of a rather significant size and volume. Power stations to contain the effect of the tidal force of the Earth's water resources is a new business, but quite promising.
Watch a video about the ebb and flow:
The study of the concept of ebb and flow on Earth, their influence on the life cycle of the planet, the mystery of the origin of killer waves - all this remains the main questions for scientists specializing in this field. The solution to these aspects is also interesting for ordinary people who are interested in the problems of the influence of foreign factors on the planet Earth.
The water surface level in the seas and oceans of our planet periodically changes, fluctuates in certain intervals. These periodic fluctuations are ebb and flow of the sea.
The picture of the ebb and flow of the sea
To visualize picture of the ebb and flow of the sea, imagine that you are standing on a sloping ocean shore, in some bay, 200-300 meters from the water. There are many different objects on the sand - an old anchor, a little closer a large pile of white stone. The iron hull of a small boat, which has fallen on its side, lies not far away. The bottom of his body in the bow is heavily weathered. Obviously, once this ship, being not far from the coast, flew into the anchor. This accident happened, in all likelihood, during low tide, and, apparently, the ship has been lying in this place for more than one year, since almost all of its hull has managed to be covered with brown rust. You are inclined to consider the unwary captain to be the culprit of the ship accident. Apparently, the anchor was the sharp weapon that the ship fell on its side hit. You are looking for this anchor and cannot find it. Where could he go? Then you notice that the water is already approaching a pile of white stones, and then you guess that the anchor you saw has long been flooded by a tidal wave. The water "comes" on the shore, it continues to rise further and further upward. Now the heap of white stones was almost all hidden under the water.The phenomena of the ebb and flow of the sea
The phenomena of the ebb and flow of the sea people have long been associated with the movement of the moon, but this connection remained a mystery until the brilliant mathematician Isaac Newton did not explain on the basis of the law of gravitation discovered by him. The reason for these phenomena is the action of the attraction of the Moon, exerted on the water shell of the Earth. Another famous Galileo Galilei connected the ebb and flow with the rotation of the Earth and saw in this one of the most reasonable and reliable evidence of the validity of the teachings of Nicolaus Copernicus, (more:). The Paris Academy of Sciences in 1738 announced a prize to the one who gives the most substantiated presentation of the theory of tides. The award then received Euler, Maclaurin, D. Bernoulli and Cavalieri... The first three took Newton's law of gravity as the basis of their work, and the Jesuit Cavalieri explained the tides on the basis of Descartes's vortex hypothesis. However, the most outstanding works in this area belong Newton and Laplace, and all subsequent research is based on the findings of these great scientists.How to explain the phenomenon of ebb and flow
How most clearly explain the phenomenon of ebb and flow... If, for simplicity, we assume that the earth's surface is completely covered by a water shell, and look at the globe from one of its poles, then the picture of sea tides can be presented as follows.Lunar attraction
That part of the surface of our planet that faces the Moon is closest to it; as a result, it is exposed to greater force lunar attraction than, for example, the central part of our planet and, therefore, is pulled towards the Moon more than the rest of the Earth. Because of this, a tidal hump is formed on the side facing the Moon. Simultaneously with this, on the opposite side of the Earth, the least subjected to the attraction of the Moon, the same tidal hump appears. The earth therefore takes the form of a figure somewhat elongated along a straight line connecting the centers of our planet and the moon. Thus, on two opposite sides of the Earth, located on one straight line that passes through the centers of the Earth and the Moon, two large humps are formed, two huge water blisters... At the same time, the two other sides of our planet, located at an angle of ninety degrees from the points of maximum tide indicated above, are experiencing the greatest ebb tides. Here water falls more than anywhere else on the surface of the globe. The line connecting these points at low tide is somewhat reduced, and thus the impression of an increase in the elongation of the Earth in the direction of the maximum tidal points is created. Due to the lunar attraction, these points of maximum tide constantly retain their position relative to the Moon, but since the Earth rotates around its axis, during the time of the day they seem to move across the entire surface of the globe. So in each area during the day there are two high tides and two low tides.Solar ebb and flow
The sun, just like the moon, by the force of its attraction produces the ebb and flow. But it is located at a much greater distance from our planet compared to the Moon, and the solar tides that occur on Earth are almost two and a half times smaller than the lunar ones. So solar tides, are not observed separately, but only their effect on the magnitude of the lunar tides is considered. For example, the greatest ebb and flow of the sea occurs during full moons and new moons, since at this time the Earth, the Moon and the Sun are on the same straight line, and our daylight by its attraction enhances the attraction of the Moon. Conversely, when we observe the moon in the first or in the last quarter (phase), there are least sea ebb and flow... This is because in this case the lunar tide coincides with sunshine... The action of the lunar attraction decreases by the amount of the Sun's attraction.Tidal friction
« Tidal friction»Existing in our planet, in turn, has an effect on the lunar orbit, since the tidal wave caused by the lunar attraction has the opposite effect on the moon, creating a tendency to accelerate its motion. As a result, the Moon is gradually moving away from the Earth, the period of its revolution increases, and it, in all likelihood, lags a little behind in its motion.The magnitude of sea tides
In addition to the relative position in space of the Sun, Earth and Moon, on tide magnitude in each particular area, the shape of the seabed and the nature of the coastline are influenced. It is also known that in the closed seas, as, for example, in the Aral, Caspian, Azov and Black, ebb and flow are almost not observed. They can hardly be found in the open oceans; here the tides barely reach one meter, the water level rises very slightly. But on the other hand, in some bays there are tides of such colossal magnitude that the water rises to a height of more than ten meters and in some places floods colossal spaces.
Ebb and flow in the air and solid shells of the Earth
Ebb and flow also occur in the air and solid shells of the Earth... We hardly notice these phenomena in the lower layers of the atmosphere. For comparison, let us point out that ebb and flow are not observed at the bottom of the oceans either. This circumstance is explained by the fact that mainly the upper layers of the water envelope are involved in tidal processes. The ebb and flow in an air envelope can be detected only with a very long-term observation of changes in atmospheric pressure. As for the earth's crust, each part of it, due to the tidal and ebbling action of the moon, rises twice and falls twice by about a few decimeters during the day. In other words, the fluctuations of the solid shell of our planet are approximately three times less than the fluctuations in the level of the surface of the oceans. Thus, our planet seems to be breathing all the time, taking deep breaths and exhalations, and its outer shell, like the chest of a great miracle hero, sometimes rises a little, then drops. These processes occurring in the solid shell of the Earth can be detected only with the help of instruments used to register earthquakes. It should be noted that ebb and flow occur on other world bodies and have a tremendous impact on their development. If the Moon were stationary in relation to the Earth, then in the absence of other factors affecting the delay of the tidal wave, anywhere in the world every 6 hours there would be two high tides and two low tides per day. But since the Moon continuously revolves around the Earth and, moreover, in the same direction in which our planet rotates around its axis, a certain delay is obtained: the Earth manages to turn to the Moon with each of its parts not within a day, but at about 24 hours and 50 minutes. Therefore, in each locality, the ebb or flow does not last exactly 6 hours, but about 6 hours and 12.5 minutes.Alternating ebb and flow
In addition, it should be noted that the correctness alternating ebb and flow is violated depending on the nature of the location of the continents on our planet and the continuous friction of water on the surface of the Earth. These alternation irregularities sometimes reach several hours. Thus, the most "high" water occurs not at the moment of the Moon's climax, as it follows according to the theory, but several hours later than the Moon's passage through the meridian; this delay is called the applied hour of the port and sometimes reaches 12 hours. Previously, it was widely believed that the ebb and flow of the sea were associated with sea currents. Now everyone knows that these are phenomena of a different order. A tide is a kind of wave motion, similar to that which occurs due to the wind. When a tidal wave approaches, a floating object oscillates, as with a wave arising from the wind - forward and backward, down and up, but it is not carried away by it like a current. The tidal wave period is about 12 hours and 25 minutes, and after this period of time the object usually returns to its original position. The force that causes hot flashes is many times less than the force of gravity... While the force of attraction is inversely proportional to the square of the distance between the attracted bodies, the force that causes tides is approximately is inversely proportional to the cube of this distance rather than squaring it.Who wouldn't want to take a walk to the bottom of the sea? "It's impossible! you exclaim. - For this you need at least a caisson! " But don't you know that large areas of the seabed open up for observation twice a day? True, woe to those who decide to stay at this "exhibition" beyond the established time! The seabed opens at low tide. - this is a change of high and low water. This is one of the mysteries of nature. Many naturalists tried to solve it: Kepler who discovered the law of planetary motion, Newton who established the basic laws of motion, the French scientist Laplace, who studied the emergence of celestial bodies. They all wanted to penetrate the secrets of the life of the oceans... The wind creates waves on the sea. But the wind is too weak to control the ebb and flow. Even a storm can only help with the tide. What gigantic forces are doing such hard work?
The influence of the moon on ebb and flow
Three giants are fighting for the world's oceans: The sun, the moon and the earth itself... The sun is stronger than all, but it is too far from us to be the winner. The movement of water masses on Earth is mainly controlled by the Moon. Located 384,000 kilometers from Earth, it regulates the "pulse" of the oceans. Like a huge magnet, the Moon pulls masses of water up several meters while the Earth rotates on its axis. Although the difference between the heights of ebb and flow is on average no more than 4 meters, the work that the moon is doing is enormous. It is equal to 11 trillion horsepower. If this number is written in numbers alone, then it will have 18 zeros and look like this: 11,000,000,000,000,000,000. You cannot collect such a number of horses, even if you drive herds from all "ends" of the globe.Ebb and flow - sources of energy
After the sun ebb and flow- The biggest energy sources... They could give electricity all over the world. Since time immemorial, man has tried to make the moon serve him. In China and elsewhere, tidal waters have been driving millstones for a long time.
In 1913, the first "lunar" power station was put into operation in the North Sea near Husum. In England, France, the United States and especially in Argentina, feeling a shortage of fuel, many bold projects for the construction of tidal stations have been created. However, Soviet engineers went farthest, who created a project for the construction of a dam 100 kilometers long and 15 meters high in the Mezen Bay of the White Sea. At high tide, a reservoir with a capacity of 2 thousand square kilometers is formed behind the dam. Two thousand turbine generators will provide 36 billion kilowatt-hours. This amount of energy was produced in 1929 by France, Italy and Switzerland combined. A kilowatt hour of this energy will cost about a penny. Unfortunately, the "pulse" ebb and flow of the sea beats with unequal strength, like the pulse of a person. The tides do not provide a constant, uniform flow of water, and this makes the project difficult. The tide is strongest when the Sun and Moon pull masses of water in the same direction. High tides when the water level rises up to 20 meters, are at full and young moon... They are called "syzygy". In the first and last quarter of the month when the moon is at right angles to the sun, tides are lowest and are called "quadrature". The ebb and flow of the sea are very important for navigation, and therefore their offensive calculated in advance... This calculation is so difficult that it takes many weeks to compile the annual tide calendar. But the inventive mind of man has created a calculating machine, the "electronic brain" of which makes predictions of tides in two days. The tide calendar shows that tidal waves travel across the globe at regular intervals. From the sea shores, they rise into rivers.
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