# Electromagnetism images

Electromagnetism

What is electricity?

What is magnetism?

How are they related?

Static electricity:

Friction rubs some electrons off leaving a charge.

The other two ways of charging something:

Terms you need to know about moving elevtricity: Voltage, Resistance, and Current

Voltage is the driving force; measured in Volts (V)

Resistance is the opposition to flow; measured in Ohms (R or ____)

Current is the actual flow of electrons; measured in Amps (I)

Mathematically is looks like this:

For electrons to move, there must be a source of electrons (i.e. battery) and something for them to conduct through (i.e. wires).  Add a load that converts the moving electrons into some other form of energy and you have a circuit.  Remember, the wires must connect back to the power source.

Circuits may be in series or parallel:

Those moving electrons may move in one direction (direct current) or back and forth (alternating current).

Batteries are DC and outlets are AC.

So, how do we generate electricity?

Chemical reactions (like in batteries) can make electrons flow.  Sunlight (like in solar panels) can make electrons flow.  But most electricity in the world is made by making a magnet move inside a coil of wires:

If you move a magnet in a coil of wires, you generate electricity.  You may use steam to move that coil as in this picture, or wind, or water, or just about anything.  If you move it using something that does not get used up, we call it renewable.  If you move it using something consummed (oil, gas, coal, wood, etc.), we call it non-renewable.

This works in reverse as well.  If you move electrons through a wire in a magnetic field, you generate movement:

Here is how the US makes its electricity: