Electromagnetic Spectrum

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.

The "electromagnetic spectrum" of an object is the distribution of electromagnetic radiation emitted or absorbed by that particular object.

Basically, it is the entire frequency range of electromagnetic waves.

Maxwell's Equations

Maxwell's equations relate the electric and magnetic fields to their sources.

Basically, the equations show that light is an electromagnetic wave.

ELECTROMAGNETISM.

So after reading about electricity and magnets, we can now join the 2 together to lern about electromagnetism.

Electromagnetism is one of the four fundamental reactions of nature. (The other forces are the strong nuclear force, the weak nuclear force and the gravitaional force.)

It is the force that causes the interaction between electrically charged particles. These particles are in electromagnetic fields.

The two ideas of elctricity and magnetism are interdependent because a changing electric field generates a magentic field, and a changing magnetic field produces an electric field.

The unification of this was a giant step forward in scientific discovery!

Basically, electromagnetism describes the interactions of light (that is electric fields and magnetic fields) on matter and charged particles.

The basics of electromagnetism were developed by physicists in the 19th century, mainly by James Clerk Maxwell who primarily unified the idea.

Electromagnetism obeys a set of equations called "Maxwell's equations" (http://en.wikipedia.org/wiki/Maxwell%27s_equations) and the electromagnetic force is given by the "Lorentz force law".

According to Maxwell's equations, the speed of light in a vacuum is a universal constant, dependent only on the electrical permittivity (permittivity is the measure of how much resistance is encountered when forming an electric field in a vacuum) and magnetic permeability (permeability is the measure of the ability of a material to support the formation of a magnetic field within itself) of free space.

There are also things called electromagnets. An electromagnet is a type of magnet whose magnetic field is produced by the flow of electric current. The magnetic field disappears when the current ceases.

Unifying the ideas :D

Let's Learn Magnets

To read more, click the heading above to link to wikipedia :)

Understanding magnets are also key to learning about electromagnetism.
They work in a particular way that also links in with electricity.

A magnet has a positive and negative charge to it and creates it own 'magnetic field'. These are called poles and every magnet has them. There magnetic strength is the most powerful at the poles.

Magnestism, as in electromagnetism, is the force where objects are attracted or repelled to one another. Usually these objects are metals such as iron.

Interesting fact: When a magnet is broken into little pieces, a north pole will appear at one of the broken faces and a south pole. Each piece, regardless of how big or small, has its own north and south poles.

Franklin's Kite Experiment

Discovering Electricity

• Benjamin Franklin (1706-1790) – His kite experiment demonstrated that lightning is electricity. He also was the first person to use the terms positive and negative charge.

• William Thomson, Lord Kelvin (1824- 1907) –They calculated after a lot of mathematics that the lowest temperature possible for any state of matter to reach is -273° C. This relates to electricity because when objects are at very low temperatures, they become ‘super conductors’, meaning they can conducts large amounts of electricity.

• Thomas Seebeck (1770-1831) – He discovered thermoelectricity.

• Michael Faraday (1791-1867) – He worked on how electric currents work and was one of the most successful scientists in the field of electricity. His work helped scientists even one hundred years later. He was never set back by failure. He would say; "the failures are just as important as the successes." He felt failures also teach. The farad, the unit of capacitance is named in the honor of Michael Faraday.

• James Maxwell (1831- 1879) – He used Faraday’s work to turn it into a mathematical expression. The unit used for electromagnetism was named in his honor.

• Albert Einstein (1879 – 1955) – Arguably one of, if not the most famous, scientist of all time, Einstein proved that one gram of mass can be converted into an amount of energy. E=MC^2.


Discovering electricity could not be done without all of the work from these noted scientists and many others. There work all helped each other to excel in a related area.