Magnetic field how does it work

It is necessary to paint arrows differently for each hemisphere in order for the compass to point exactly to the nearest pole. But every compass has a secret. Compasses for the Northern Hemisphere, for example, where the red arrow should point north, in fact, absolutely always point to the magnetic south of the Earth! The thing is that near the geographic North Pole of the Earth the magnetic field lines actually enter the planet, i. But for convenience, people still decided to call the pole at the North Pole "north" and the pole at the South Pole "south".

If you thought there's probably a big lump of iron in the center of the planet,' you're right. But this is a very incomplete picture. We recall that at three thousand kilometers under the ground the core of the planet begins. In size, it can be compared to Mars, but in fact, the core consists of two parts - an external liquid core and a solid inner core. The inner core is really a lump of pure iron, but its magnetic properties are insufficient to provide that powerful and mobile magnetic field that the Earth has.

The main actor here is the outer, liquid part of the core, which also mainly consists of iron. Because of the rotation of the Earth, the substance there is in constant motion - it rotates around the center of the planet.

And because it is a liquid, different velocities are possible there: the closer to the center, the faster the matter moves. Remember at the beginning of the article we emphasized that magnetic fields are always where electrons move?

This is also very important for processes in the Earth's core, because liquid iron serves as an excellent conductor - an environment for the movement of electrons.

Say, in the process of formation, the Earth got a very weak magnetic field just from having iron inside the core. The solid core began to cool gradually, and streams of hot matter began to rise from the core upwards, towards the mantle.

And from above, from the mantle to the core, streams of cooler matter began to descend. Exactly like in the atmosphere, where warm air always tends upwards, as it is less dense, and cold air, being heavier, moves downwards. But the Earth rotates - so does the matter in the liquid core, and at different speeds. Therefore, these flows swirl, i. As a result of all this motion, iron atoms are constantly 'rubbing' against each other, exchanging electrons.

And the more the electrons move, the more new magnetic fields are born, which at the right angle can join at the poles and reinforce each other. All these fields are bound to the flows of the substance, so they revolve around the center of the Earth along with the liquid iron. And because they are constantly inside the lines of the weaker, 'original' magnetic field of the Earth, they are able to 'drag' and amplify its lines. It is not easy to show what happens to the magnetic field lines in the core - usually, you get something like spaghetti stuck together in a pot.

It turns out that the fluxes of the substance in the liquid core independently give birth to more and more magnetic fields, whose lines capture and make the electrons nearby move, and they give birth to other magnetic fields, which 'capture' even more electrons Old and new fields overlap.

As a result, the magnetic field spontaneously increases to the maximum possible at the moment. The term dynamo effect has been coined for this process. The dynamo itself does not create the Earth's magnetic field, but strengthens and maintains the existing one. James Powell and Gordon Danby of Brookhaven received the first patent for a magnetically levitated train design in the late s.

The idea came to Powell as he sat in a traffic jam, thinking that there must be a better way to travel on land than cars or traditional trains. He dreamed up the idea of using superconducting magnets to levitate a train car.

Superconducting magnets are electromagnets that are cooled to extreme temperatures during use, which dramatically increases the power of the magnetic field. The first commercially operated high-speed superconducting Maglev train opened in Shanghai in , while others are in operation in Japan and South Korea.

In the United States, a number of routes are being explored to connect cities such as Baltimore and Washington, D. In Maglev, superconducting magnets suspend a train car above a U-shaped concrete guideway. Like ordinary magnets, these magnets repel one another when matching poles face each other. The magnets employed are superconducting, which means that when they are cooled to less than degrees Fahrenheit below zero, they can generate magnetic fields up to 10 times stronger than ordinary electromagnets, enough to suspend and propel a train.

Testing materials in the presence of magnetic fields and examining the magnetic properties of the atoms that make these materials can tell you about their magnetism.

They have no or few unpaired electrons to let charges flow through. These moments are their ability to align with an external magnetic field due to the spin of unpaired electrons in the orbitals of the atoms that make these materials.

In the presence of a magnetic field, the materials align to oppose the force of the magnetic field. Paramagnetic elements include magnesium, molybdenum, lithium and tantalum. Within a ferromagnetic material, the dipole of the atoms is permanent, usually as the result from heating and cooling paramagnetic material.

This makes them ideal candidates for electromagnets, motors, generators and transformers for use in electrical devices. Diamagnets, by contrast, can produce a force that lets electrons flow freely in the form of current that, then, creates a magnetic field opposite to any magnetic field applied to them. This cancels out the magnetic field and prevents them from becoming magnetic.

Magnetic fields determine how magnetic forces can be distributed in the presence of magnetic material. While electric fields describe the electric force in the presence of an electron, magnetic fields have no such analogous particle upon which to describe magnetic force. Scientists have theorized that a magnetic monopole may exist, but there hasn't been experimental evidence to show that these particles exist.

If they were to exist, these particles would have a magnetic "charge" much the same way charged particles have electric charges. Magnetic force results due to the electromagnetic force, the force that describes both electrical and magnetic components of particles and objects.

This shows how intrinsic magnetism is to the same phenomena of electricity such as current and electric field. The charge of an electron is what causes the magnetic field to deflect it through magnetic force much the same way electric field and electric force do.

While only moving charged particles give off magnetic fields, and all charged particles give off electric fields, magnetic and electromagnetic fields are part of the same fundamental force of electromagnetism. The electromagnetic force acts between all charged particles in the universe. The electromagnetic force takes the form of everyday phenomena in electricity and magnetism such as static electricity and the electrically charged bonds that keep molecules together.

This force alongside chemical reactions also form the basis for the electromotive force that lets current flow through circuits. When a magnetic field is viewed intertwined with an electrical field, the resulting product is known as an electromagnetic field. The particle will continue to move without being deflected by the magnetic field. In the diagram above, the right-hand rule also demonstrates the relationship between magnetic field, magnetic force, and current through a wire.

This also shows the cross-product between these three quantities can represent the right-hand rule as the cross-product between the direction of the force and the field equals the current's direction. Magnetic fields of around 0.