Magnetic Levitation

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Since I have put a lot of effort into the creation of my last article I don't consider the visibility it has had to be fair, not that I complain about it, but I take it as a sign that I must look for other alternatives to not feel that my work is in vain, that's why I have created my own blog wordpress compatible with steemit and in addition to that today I will share that article with people in the English language. In the future I will do some articles in English and in the end I will decide to publish them in the language that has the greatest acceptance.

I think that in the previous topics I have been too expressive in a mathematical language a little classic leaving aside the explanatory words to users who with interest in learning find complexity in such expressions making the reading of the article frustrating. Of all the users who have supported me, the sincerity of one of them has made me reflect that not all of us feel the same love for specific subjects, even though we are all attracted by something in life, there is a diversity of tastes and a diversity of tendencies. It could be said that this is the emotional basis of the attraction and sentimental repulsion for which I decided to change the subject matter of my contents to a simpler language without losing the scientific essence, technological and of course educational, in that sense today's article is more of the physical type choosing a mind-blowing subject like magnetic levitation, I hope to be better this time and remember that I love suggestions because they help us improve our content by enriching it with new ideas from you.

### Electromagnetism

In order to understand magnetic levitation, we must study electromagnetism. It was not until 1821 that the Danish physicist Hans Christian Oersted discovered its existence by accident, although we can previously say that magnetism found its application in the 19th century. Devices such as the telephone and the telegraph were battery-powered devices, with the discovery of Oersted a giant step forward was taken in electromagnetic induction engineering applications, giving rise to the electric motor and the dynamo, which would later provide us with a technological era of great possibilities. With the expansion of this knowledge there was a succession of increasingly sophisticated inventions among which we can include a bipolar generator in 1878 created by Edison, a year before inventing the electric light filament, we must also mention Hertz with his experiments that served as a basis for the wireless transmission of radio waves without which it would not be possible to communicate over long distances as we do today thanks to our telephones and satellites, in the same line emerged devices such as radio and television, None of this would be possible without electromagnetism but one of the applications that I find amazing and innovative is that nowadays, there is a train capable of travelling at a speed of 518 km/h using magnetic levitation, electromagnetism consists of creating a magnetic force by means of an electric current in a coil, where the magnetic field is associated with the current intensity which makes the coil function like a magnet, in other words the coil becomes a magnet whose strength depends on the electric current flowing through it and other physical factors. If we can make a coil work as a magnet it is important to mention that it can exert force in two directions depending on the poles, generally we know and use the force of attraction in magnets and energized coils for relay effects and devices in which it is convenient that the force of the magnetic field be of attraction, however for magnetic levitation effects one of the principles of the magnetism used is the repulsion between equal poles.

### Levitation

It is the effect by which a physical body can remain suspended in the air without the help of a supporting element, the body "floats" in the air in a stable way without being disturbed by the attraction of gravity¹ At this point I risk saying that a person floating in a pool x centimeters from the bottom is in a state of levitation, although the density of the water gives him the facility to do so there are other factors that influence since from experience we cannot all do so without a certain concentration (the desperate one sinks 😁), it's just an analogy, out of the water it's amazing because it's not a common and rarely seen phenomenon, in fact some illusionists have made money causing these impressions in the audience, but I don't want to get out of the scientific point so I keep telling you that the levitation of an object according to today's technology is possible even with several techniques among which are;

- Electrostatic levitation: For this purpose, the object being levitated must be electrically charged so that a force equal to and opposite to that of gravity is produced with a suitable electric field. This type of levitation is the one that occurs, for example, in the classic oil drop experiment carried out for the first time by Robert Millikan.

Magnetic levitation: This version is also known as pseudo-levitation, since it actually requires additional binding, such as the above-mentioned thread), that due to superconductivity (specifically due to the Meissner effect), that due to diamagnetism, or electromagnetic suspension (which, with the help of servomechanisms, is applied in magnetic levitation trains).

Aerodynamic levitation: in this case, the variations in the pressure exerted by gases to maintain objects in a stable position are played with, as in the case of helicopters (airplanes cannot be considered objects in levitation, since, with some exceptions such as the McDonnell Douglas AV-8 Harrier II, they need to be in motion, so it cannot be said that they are in a stable position).
Acoustic levitation: this is possible due to the non-linear effects of intense sound waves, although in practice this has only been done with objects of a few grams of mass.

Optical levitation: uses radiation pressure to make low-mass objects levitate, using the principle of conservation of momentum (the object absorbs the photons, so their momentum is transferred to the object in levitation). Lasers are usually used in this type of levitation.

Antigravity: A form of levitation that has not been observed or demonstrated. According to certain hypotheses in the field of theoretical physics. Under certain physical conditions objects would be gravitationally repelled (so that they would have a "negative mass") by the action of antigravitons (the hypothetical antiparticle of graviton) instead of attracted. However, according to the main current lines of research, it is considered unlikely or undemonstrable that antigravity as such could exist. The lack of scientific evidence, coupled with the current misunderstanding of a quantum theory of gravity, has led many science fiction authors to incorporate this form of levitation into the plots of their literary production.

At this point we should be clear that this article is focused on magnetic levitation 😁 A body suspended in the air is levitating, if we can give it movement it should be able to increase its speed more easily compared to another body that is not levitating because the former does not need to overcome the friction force exerted by the friction with the surface on which it rests because it is literally not supported on any but suspended by a phenomenon called magnetism. This is how a train based on magnetic levitation is suspended in air avoiding friction with the rails.

During my experience as a physics teacher I have found that most students lack the basic knowledge necessary to understand everything related to magnetism, at a basic, diversified level and even in higher education, without these bases it is impossible to understand electromagnetism which also includes knowledge of electricity and relationships between electric and magnetic fields.

### Magnetic levitation

As I said a few paragraphs ago when we consider magnetism we must take into account that there are two forces according to the opposite poles, these are attraction for different poles and repulsion for equal poles. If we place two magnets whose opposing sides are equal poles there will be a repulsive force, if for example we put them in a cylinder so that they cannot rotate to change the opposite pole then the impan placed at the top will be kept in a state of levitation driven by the magnet at the bottom, because this levitation is caused by a magnetic field we call magnetic levitation.

The study of magnetism began with the discovery of magnets by the Greeks, and its scope has gone as far as achieving the levitation of a train in Japan ³.

In the 19th century, Oersted and his discovery of the relationship between the electric charges circulating in a conductor and the magnetic field generated around it gave rise to a new branch of physics called Electromagnetism ⁴.

### Applications

As far as electromagnetism is concerned, the applications are very large in numbers: electric motors, load-bearing electromagnets, transformers, sound systems, telecommunications, intelligent electronic devices, wireless chargers, and in recent decades, magnetic levitation.

The application with the greatest technological impact for magnetic levitation is the aforementioned trains, which are capable of reaching high speeds, giving the user the sensation of a plane ride not only because of their speed but also because there is no friction due to the fact that they are not physically attached to the rails. The trend of this technology is focused on the creation of an aerospace propulsion system with techniques based on the technology of levitating trains (MagLev).
There are two points on a magnet that should be especially considered: one near each end, at which the attraction is maximum. Close to its median attraction effect is "zero" (neutral plane) ⁵.