Rube Goldberg Machine

Taylor McWey;William Mueller;Daniel Tuck

Mr. O'Neill

Physics, Period 3


Our machine would help people who have up set stomachs or who need to put tablets in water.  The example that we will use in our experiment will be putting Alka-Seltzer tablets into a glass of water.  Our goal is to be a complex way by using simple machines to launch Alka-Seltzer tablets into a glass of water.

Description of Model

            Our machine will put tablets into a glass of water.  We are starting of by rolling a marble down a maze.  The marble then rolls into a funnel.  Then it rolls through a tube and knocks over a domino that starts a chain reaction of falling dominoes. The dominoes then knock over a weight that releases a pendulum that will collide with another row of dominoes.  The dominoes will then hit another weight, which will cause a lighter to ignite. The flame will sever a string holding another weight.  The weight will fall and land on a small catapult launching tablets into the glass of water.

Theoretical Background

            Most of the energy transfers taking place in our machine are from one object transferring its momentum to another as it falls.  However, there is one step in our machine that sends a marble into a funnel and as it spins the marble is acted upon by centripetal force.   Another step has a pendulum hanging with stored potential energy, but when a block is moved by a row of falling dominoes the potential energy is transferred into kinetic energy.  After that, a weight drops and pulls down the switch on a lighter, converting the energy form the weight into thermal energy.  As the flame burns a string it releases another weight to fall on a small catapult.

Data Section



1. On our original design we were going to have a flame burn through a rope to drop a weight, but we couldn’t find a way to ignite the lighter.

2. We attempted to use a pendulum to knock over dominoes.


3. The tablets were originally going to be launched into the glass by a catapult, but the direction of the tablets was too unpredictable.



4. The original weight we used to cut the scissors was too light, and could not get enough force to close them.

1. We attached scissors to our project and had a weight fall from a board to tighten the scissors and cut the string.


2. We connected a tube to the end of a funnel so the marble would hit the dominoes.

3. We set up a domino at the end of the catapult and attached a piece of paper to the rim of the glass.  The tablets were on top of piece of paper inside the glass.  The domino then launched up and hit the paper causing the tablets to slide into the glass. 

4. We made the weight bigger so there would be more force.



Discussion of Results

The final model of our project consisted of a maze of marble works that led to a funnel. The funnel directed a marble into a row of dominos.  The dominos collided with one another until they collided with a small weight.  That weight was connected a pair of scissors which clamped shut over a string releasing a weight.  The weight then fell onto a small catapult launching a domino into the air.  The domino collided with a piece of paper that was attached to a glass of water.  On top of the inside edge of the paper were two Alka-Seltzer tablets, which slid into the cup of water producing our final product.  The most difficult part of this machine would be the dominos.  If not set up correctly at the end they will not knock the weight off.  Other than that the machine works very well.  Over time the paper might need to be changed, and the weight that closes the scissors.  Also, the string that holds the weight that falls on the catapult must be reset after every use.  Otherwise it is very durable.


The process of completing this project began, for the most part, over winter break and officially ended the night before the presentations.  Building the project and getting everything to work correctly and consistently was a combined effort on all our parts.  There were times when several hours would be spent just trying to figure out how to make one thing work.  One example of this was how to get the scissors to cut the string.  Half of one day was spent on just this, and in all actuality our solution came about by accident.  We had meant for the scissors to be pulled together by a weight falling, but what we didn’t see coming was the swinging motion that came from only one nail holding the scissors to the board.  This worked out to our advantage in the end, and was just a total accident.  Another challenge was getting everyone together at one place, at the same time.  As far as successes are concerned, every time a part of the machine worked it was a success.  Specifically, the greatest successes would have to be the scissors and the final phase involving the domino launcher.  The project was great, we all agree on the scissors vicious cut to be our favorite part, however, the domino launcher was a close second.  Just working with a group of people that you know and enjoy being with was great.  In order to improve the project, I suggest a simpler and more easier to understand write-up.  Building the machine was much easier than the write-up.  Looking back our overall opinion would be that this was an enjoyable project and a welcome break from the note packets and review sheets. 


Physics Video!


Rube Goldberg

Simple Machines