Model that demonstrates conservation of mechanical energy

[furia]

My physics class is currently invovled with a project regarding conservation of mechanical energy.

I will need to choose or create a model that will demonstrate conservation of mechanical energy, then analyze the model and explain it.

Does anyone know of any model that can be made easily and can demonstrate conservation of mechanical energy in a simple way, such as the balance ball, or pendulum.
( The balance ball and pendulum are restricted models of this project)

[Pseudo Statistic]

How about a spring and a ball?

[berkeman]

Or maybe those cool toys with several metal balls suspended on V-strings all lined up and touching, where you pull one out at one end and let go, and when it hits it knocks out the ball on the other end out to the same max height? Those are fun, and may be different enough from a standard 1-ball pendulum that your instructor will allow it.

[furia]

spring and ball, please go in abit further on that. the balls on v string is also known as the balance ball, so i cant use that

[berkeman]

By spring and ball, I think Pseudo means a mass on the end of a spring. If you can't use the balance ball, how about a roller coaster? Once you get towed to the top of the first big hill, it's all PE<-->KE from there on down. Maybe even add in some of the upside-down corkscrew sections....

[furia]

maybe something like that, not too complicated or i wont be able to make it out of normal house stuff