Rube Goldberg Project:

Explanation:  A lacrosse ball rolls down a tube.  The ball hits one action figure and the action hits the one in front, like dominos.  The line of about 15 action figures turns in front of the stairs and the last one hits a water bottle.  The water rolls down the stairs and hits another action figure. The action figure hits a small metal weight which rolls down a game board and rips the blue tape holding up the dumbbell.  The dumbbell falls and hits the drum pedal causing it to hit the ping pong ball in the tubing.  The ping pong ball rolls down the tube and hits a cowbell.

Simple Machines used: First tube with lacrosse ball- Incline Plane. Action Figures - Lever The stairs that the water bottle rolled down – Incline Plane The game board that the small weight rolled down – Incline Plane The drum pedal – Lever Cardboard tubing with ping pong ball – Incline Plane

Forces Used: The lacrosse ball has potential energy due to gravity in the top of the tube and turns to kinetic energy when it is rolling down the tube. It also has momentum which acted on the action figures and continued through the domino effect of action figures. On the stairs, when the action figure hits the small weight, its momentum and the force of gravity from the incline plane rolls the weight down the game board. This is also an Elastic Collision The dumbbell is being held up by the friction of the tape and has potential energy. When the small weight breaks the tape and the potential energy turns into kinetic energy due to the acceleration of gravity. The kinetic energy is transferred into the drum pedal and then transferred into hitting the ping pong ball, gravity is also present in moving the ping pong ball since it is on an inclined plane.

Problems and Solutions There were two problems we ran into during our trials: 1.When we rolled the lacrosse ball down the tube is kept missing the action figure so we had to keep retrying it until we had it just right. 2.When the water bottle has hit by the last action figure it either wasn’t enough to push it down the stairs or the water bottle didn’t hit the other action figure three steps down. The ways we fixed these problems were by repositioning the tube and the action figure on the stairs. We also added and took away some water from the water bottle to see exactly how much we needed. We wanted not too much to the point where it was too heavy to get pushed down the stairs by the action figure but also enough so that it would make a straight path down the stairs and effectively hit the other action figure.