this is we project. The name gardan machine
At the beginning we used the gravity of the ball to move it down，We use the foam on the corner of the first pipeline, shall be the bubble will slow to let the ball, also can let the ball perfect falls in the location specified by us, the last step of the way we use to let the ball down, hit the bottom of the ring.
In this project, we used kinetic energy, friction force and sound energy