Magnetism and Electromagnetism: Concepts and Explanations Magnetic

Magnetism and Electromagnetism: Concepts and Explanations

Magnetic Polarity

Magnetic polarity states that all magnets have a North and South pole. Each pole is attracted to each other just as the polarity of the Earth is attracted to itself. The most effective magnets in production are referred to as North Pole Magnets, due to the fact that they only attract South Pole magnets. Magnets can be either North Pole magnets or bi-polar, meaning that they posses on of each pole. As far as polarity is concerned, opposite poles attract and similar poles repel each other. This is the most basic concept associated with magnetism, and one that can be replicated using electrical current or electromagnets.

Example: If a magnet is touched to another, the two opposite poles will attract and the two similar poles will repel each other. This can be seen in a very basic experiment using two bi-polar magnets.

Magnetic Lines of Force

These are the lines draw to help illustrate magnetic fields. These force lines run north or south, depending on the magnet's orientation. This means that the polarity, and magnetic field, are directly related to the strength of the magnet and "orbit" around the pole of the magnet, as depicted in the picture. These lines of force, similar to how electricity is drawn to show electric forces or flows, help to show how a magnet interacts with the environment around it. In other words, the direction of a magnetic line of force at any point gives the direction of the magnetic force on a north pole placed at that point.

There are four main properties of magnetic lines of force. They are as follows:

1. The magnetic lines of force originate from the North Pole of a magnet and end at its South Pole.

This I similar to the way that north and south attract each other, but repel their own polarity.

2. The magnetic lines of force come closer to one another near the poles of a magnet but they are widely separated at other places.

The lines of force emanate and terminate at the poles of the magnets, this helps explain this property.

3. The magnetic lines of force do not intersect (or cross) one another.

They do not cross one another because their polarities attract each other and repel their own. This means that polarities cannot be intertwined or crossed within the lines of force.

4. When a magnetic compass is placed at different points on a magnetic line of force, it aligns itself along the tangent to the line of force at that point.

This also follows the basic premise that the polarities align themselves to the opposite poles while repelling their own polarity.

These lines of force represent the magnetic field. A very basic example of this is when metal shavings are placed on a table and a magnet is placed under or over them. These shavings will physically align themselves to illustrate the magnetic lines of force within the metal shavings themselves. This is an excellent way of showing how all steel shavings are magnetic in nature.

Law of Magnetic Poles

The law of magnetic poles states that opposite poles attract each other while similar poles repel each other. This is a very basic law, but one that governs the interactions of magnets. It follows that the magnetic fields are also aligned based upon the pole orientation. Each pole, representing a magnetic field, has both a direction and a magnitude. These can be used to figure out the magnets' interactions and help to determine how they will behave in a certain environment.

By rotating magnetic fields or polarities, certain mechanical advantages can be attained. This is precisely how generators and electric motors work, creating energy or movement trough the reverse polarization of magnets and by utilizing the law of magnetic poles.