For all you evil geniuses...

I have come up with a possibly already devised concept of a gauss gun.

It utilizes a Pipe, an Iron ball, alot of magnet wire, a huge battery or power source, and a control circuit

You take a small pipe, preferably pvc, and seal off one end. you then wind a LARGE coil on the other end of the pipe, and connect that to a circuit. you add some kind of trigger mechanism that will tell the circuit when the intended projectile is near the coil, and you put an Iron ball (or any other magnetic projectile) down the muzzle.

the way it works is, the coil generates a large magnetic field theat causes the Iron ball to move towards the coil, accelerating as it does this.when the trigger mechanism is, well, triggered, the coil is turned off, leaving the ball to exit the pipe and hurl towards the intended target.

the circuti would be extremely simple, consiting of possibly a transistor circuit that turns off when triggered.

I would have put an MS paint conception of the idea, but bmp files are not allowed and this school is a great example of technological ignorance, so, no picture

You've described an electromagnet and I'd guess that you know that or will eventually make that discovery. Given your interest you might try to understand the physics of the situation to see if you can actually make it work. Maybe your physics or science teacher can help out. The amount of force it takes to accelerate your projectile is easily determined. The amount of force available should also be quantifiable.

For what it's worth, a solenoid operates on this principle. The solenoid is pushed out or in with the application of current to the coil that surrounds it.

I do know what an electromagnet is, Im just wonering if it would work or not. just imagine, never having to buy ammunition again, just picking something up from the ground or the nearest junkyard and shooting that...

This is a commonly explored concept around the web, and it can work, but it is not practical as an actual weapon due to the size and charging times required. Good fun to experiment with though, so long as your careful. Heres some reading for you:

http://www.powerlabs.org/coilguns.htm

Yeah, people do that all the time.

Another, most likely better way, is to have a couple of coils along the barrel. They turn off aftter the projectile passes them.