What is Magnetism?

Magnetism is the force exerted by magnets when they attract or repel each other. Magnetism is caused by the motion of electric charges. 

Every substance is made up of tiny units called atoms. Each atom has electrons, particles that carry electric charges. Each electron has something called Electron spin. While the electron is orbiting around the nucleus of the atom, it is also spinning in a clockwise or counterclockwise direction. Their movement generates an electric current and causes each electron to act like a microscopic magnet.

The majority of the time, there is a random distribution of electron spins spin in opposite directions, which cancels out their magnetism. That is why materials such as cloth or paper are said to be weakly magnetic. In substances such as iron, cobalt, and nickel, most of the electrons spin in the same direction. This makes the atoms in these substances strongly magnetic—but they are not yet magnets. To become magnetized, another strongly magnetic substance must enter the magnetic field of an existing magnet. This aligns the spins of the electrons so all spin in the exact same direction The magnetic field is the area around a magnet that has a magnetic force.

What is a Magnetic Field

A magnetic field is the magnetic effect of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude (or strength); as such it is represented by a vector field.

Magnetic Fields will use the terms North and South Pole. The North Pole represents the positively charged pole of a magnet and the South Pole represents the negatively charged pole of a magnet.

Types of Magnetism

Permanent Magnets:

Permanent Magnets are a magnet that retains its magnetic properties in the absence of an inducing field or current. These magnets can be found occurring naturally in the world or can be man-made. Whether they are found naturally or man-made, 


A body or substance having a high susceptibility to magnetization, the strength of which depends on that of the applied magnetizing field, and which usually persists after removal of the applied field.


A form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field and form internal, induced magnetic fields in the direction of the applied magnetic field.


Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. This typically will cancel out an applied magnetic field. Silicon is diamagnetic, which is one more reason it is excellent for building electronics like the solar panel examples. 

Grain Structures

Metals, like everything else, are made up of atoms, are typically assumed to be solid spheres. For our general purposes, atoms within a metallic crystal or grain are regularly arranged over great distances, distances that are huge when compared with atomic dimensions. Where adjacent crystals join is a crystal boundary, a zone of short-range disorder. These crystal boundaries determine in no small way the useful properties of engineering materials when applied to steam generators.

All alloys are made up of many crystals of various individual orientations. These individual crystals are called"grains." In any one grain, all atoms are arranged with one particular orientation and one particular pattern. The juncture between adjacent grains is called a "grain boundary." The grain boundary is a transition region in which some atoms are not exactly aligned with either grain.

Individual grains are viewed as being made up of the cube faces of face-centered cubic or body-centered cubic iron. Grain boundaries are usually considered to be two-dimensional but are actually a finite thickness, perhaps 2-10 atomic distances.

Grain size can vary greatly depending on the alloy and heat treatment. For reference, a grain diameter is about 0.001" across. Thus there may be a billion grains per cubic inch of alloy. Within any one grain are a large number of individual atoms. The diameter of an iron atom is about 0.00000001 inch. So across a 0.001" grain there are 100,000 iron atoms. With a grain boundary perhaps 2-10 atomic dimensions thick, the grains are clearly seen to be regions of long-range atomic order, and the grain boundaries, regions of short-range atomic disorder.


If you take a look at the grain structure of iron you can see that they are relatively the same size. The black spaces in between the grains are impurities like carbon that get caught there while the molten metal cools and are called grain boundaries. You can change the grain structure and boundary size, shape, and orientation by additional treatments. This will usually only make them more uniform in shape and size. The more uniform the grains are in both size and orientation, the better they will add to the amplification of the spin of the electrons increasing the strength of the magnetic field. 


If you take a look at the grain structure of copper, you will see that the grains are not very uniform in size, shape, or orientation. This combined with the fact that the electron spins in a copper atom do not typically line up, creates a very difficult environment to permanently magnetize. For this reason, copper is Paramagnetic, meaning you can induce a magnetic field on it, but it will not hold one. 

Iron Under Magnetism

The basic science of the effects that grain boundaries impose on their structural stability and resultant electrochemical phase transformations from magnetization. You can see how the grain structures slightly shift under the magnetic field to line up better. This is at the nanoscale. 

The type of magnetism, if any, that materials will demonstrate depends on the material's ability to produce or maintain a magnetic field.  This ability to produce or maintain a magnetic field depends on a material's electron spin and grain boundaries. If both the electron spin and grain boundaries line up, they will amplify the independently weak magnetic fields produced by the spinning electrons that are normally cancelled out to be extremely strong. 

Ferromagnetic with no Magnetic Field

Ferromagnetic with Magnetic Field

Paramagnetic with no Magnetic Field

Paramagnetic with Magnetic Field

Diamagnetic with no Magnetic Field

Diamagnetic with Magnetic Field


What is Electromagnetism?

Electromagnetism is caused when an electric charge is in motion. When current is flowing through a wire, a small magnetic field is generated. More charges flowing or more coils in the inductor will amplify the electromagnetic field that a wire will produce. 


A coil is formed when you wrap a wire over itself in a circle over and over- otherwise known as an inductor. Because a magnetic field is generated in a wire with current flowing through it, wrapping a coil amplifies the total magnetic field. The magnetic field can be strengthened or weakened by adjusting the number of wraps in a coil. 

The Direction of Magnetic Fields:

The Magnetic Field Direction is determined by the direction the charges are flowing through the wire. The left-hand rule states that the magnetic flux lines produced by a current-carrying wire will be oriented in the same direction as the curled fingers of a person's left hand (in the "hitchhiking" position), with the thumb pointing in the direction of electron flow.

Solid Cores Vs- Air Cores?

Solid Cores

A solid core is any metal that can be magnetized. The metal amplifies the magnetic field. In this example, there is an iron nail that is wrapped with an electromagnet. The coil of wire induces a magnetic field and the iron amplifies its strength.

Air Cores

An air core made of anything else. Because there is no metal to amplify the magnetic field, the magnet strength is only determined by the coils.  In this example, the core of the electromagnet is literally air, but it doesn't have to be air. It can be anything that is not magnetic or has magnetic properties. 

The World's Largest Magnet!

The Earth is the world's largest magnet! Scientists do not fully understand why, but they think the movement of molten metal in the Earth’s outer core generates electric currents. The currents create a magnetic field with invisible lines of force flowing between the Earth’s magnetic poles.

The geomagnetic poles are not the same as the North and South Poles. Earth’s magnetic poles often move, due to activity far beneath the Earth’s surface. The shifting locations of the geomagnetic poles are recorded in rocks that form when molten material called magma wells up through the Earth’s crust and pours out as lava. As lava cools and becomes solid rock, strongly magnetic particles within the rock become magnetized by the Earth’s magnetic field. The particles line up along the lines of force in the Earth’s field. In this way, rocks lock in a record of the position of the Earth’s geomagnetic poles at that time.

Strangely, the magnetic records of rocks formed at the same time seem to point to different locations for the poles. According to the theory of plate tectonics, the rocky plates that make up the Earth’s hard shell are constantly moving. Thus, the plates on which the rocks solidified have moved since the rocks recorded the position of the geomagnetic poles. These magnetic records also show that the geomagnetic poles have reversed—changed into the opposite kind of pole—hundreds of times since the Earth formed.

Earth’s magnetic field does not move quickly or reverse often. Therefore, it can be a useful tool for helping people find their way around. For hundreds of years, people have used magnetic compasses to navigate using Earth’s magnetic field. The magnetic needle of a compass lines up with Earth’s magnetic poles. The north end of a magnet points toward the magnetic north pole.

Earth’s magnetic field dominates a region called the magnetosphere, which wraps around the planet and its atmosphere. Solar wind, charged particles from the sun, presses the magnetosphere against the Earth on the side facing the sun and stretches it into a teardrop shape on the shadow side.

The magnetosphere protects the Earth from most of the particles by creating a sort of force field that shifts the direction of the solar wind around the earth. This solar wind is electrically charged and beyond protecting the planet from tremendous amounts of electromagnet radiation and heat that would kill everything, the magnetosphere also protects 

Check out our page on Electric Motors to continue learning about electromagnetism and make your own electric motor project!