Re: How does electric current flow?

Electricity flows a lot like water in some ways.

For instance, water flows because it has a lot of pressure behind it, or 
because it falls down a slope.  In the case of electricity, electrons flow 
because there is a potential difference between the place where the 
electrons are and where they are trying to go to.  The measure of how much 
force is behind the electricity is called the voltage.  The higher the 
voltage, the more the electrons want to flow.

If you have a skinny pipe or hose, only so much water can come out at a 
time.  Electrical current, measured in amperes, is the quantity of 
electricity that is flowing.  Imagine the water flowing out of Niagra falls 
versus the water flowing out of your faucet.  The height of the falls is 
the "voltage", the amount of water (thousands of gallons per minute) is the 
"current".  Your faucet has 100 psi of pressure, but the faucet will only 
let a few gallons per minute through.  That is because the pipe is a 
resistance to the flow.  Electricity behaves the same way.  A resistor, 
like a light bulb, will only allow so much current to flow.  If you have a 
big fat cable, like the one between the battery and the motor in you car, 
hundreds of amps of electricity can flow.

Metals conduct electricity easily.  Other things resist the flow, like 
plastics and rubber.

To get electricity to flow, you need a complete circuit, or loop, between 
the source with the higher potential and the place where the electricity is 
going.  One path going from the battery or wall plug to the object that 
is using the electricity, and a return path.  This is where the analogy to 
flowing water breaks down.  You only need one path for water to flow.  For 
electricity, you need two paths.