Project Description
A Rube Goldberg machine is a series of complicated steps that leads up to do a simple task. My group's simple task was to staple a paper. We were required to have at least 10 steps and five of the six simple machines. We were given nine building days and three days to work on our presentation. The presentation was expected to include the basic physics behind each step, a building record, and a run-through of the machine. Our powerpoint can be viewed here. We were provided with a four foot by four foot piece of plywood. We chose to use a horizontal platform on two levels, each one 2 feet by four feet. For the simple machines, we decided to use the screw, pulley, lever, inclined plane, and the wheel and axle.
The machine was kicked off by one of us dropping a marble down a tube, which counted as our screw. The marble then rolled out of the tube and knocked a separate, larger marble, into a cup hanging underneath out board. This cup was connected to a pulley, and the string pulled up on a sort of lever, releasing another lever to swing down to our bottom level. This so called "hammer" then released a ball down a copper wire extended from the side of a plank of wood. The ball dropped down to another inclined plane, and rolled to hit another lever. This lever began a series of dominoes that became increasingly larger. The last domino fell onto a pendulum that swung around a post repeatedly before sending a cup flying. Underneath this cup was a small car, which was our wheel and axle, that accelerated into a small weight on the edge of the table. This weight pulled a string of weights off of the table, which in turn pulled out a block of wood holding a 1,000 gram mass. This mass fell onto the stapler and stapled a paper.
The machine was kicked off by one of us dropping a marble down a tube, which counted as our screw. The marble then rolled out of the tube and knocked a separate, larger marble, into a cup hanging underneath out board. This cup was connected to a pulley, and the string pulled up on a sort of lever, releasing another lever to swing down to our bottom level. This so called "hammer" then released a ball down a copper wire extended from the side of a plank of wood. The ball dropped down to another inclined plane, and rolled to hit another lever. This lever began a series of dominoes that became increasingly larger. The last domino fell onto a pendulum that swung around a post repeatedly before sending a cup flying. Underneath this cup was a small car, which was our wheel and axle, that accelerated into a small weight on the edge of the table. This weight pulled a string of weights off of the table, which in turn pulled out a block of wood holding a 1,000 gram mass. This mass fell onto the stapler and stapled a paper.
Physics Concepts
Force- Force is defined as a push or pull. It can be found by multiplying the mass of an object by its acceleration. We used this to help find the kinetic energy of the falling lever in another equation.
Kinetic Energy- Kinetic Energy is how much energy an object has because of its movement. We can calculate it by taking one half of mass times velocity squared. Another way is to use the equation work equals force times distance, because kinetic and potential energy are equal to work. We found the kinetic energy of the marble on the inclined plane.
Potential Energy- Potential energy is identified as how much energy an object has the potential to generate. It is found by multiplying height, acceleration, and mass. We found the potential energy of the pendulum and of the one kilogram mass.
Mechanical Advantage- This is how much easier a tool or machine makes a task. For example, if the mechanical advantage of a lever was 2, than it would require half as much force to do the task at hand. We found the mechanical energy of the pulley and of the lever that follows the inclined plane.
Toppling- Toppling is a chain reaction that happens when the center of gravity of an object if pushed over the edge of its base. This is the idea behind the dominoes.
Velocity- Velocity is essentially the rate that an object in a specific direction. This is different than speed itself, because speed is simply how fast something is moving.For instance, if someone walks in a circle, they may maintain their speed, but their velocity will be constantly changing. Velocity can be found by dividing the distance covered by the time it took to cover that distance. We found the velocity of the marble in the screw.
Kinetic Energy- Kinetic Energy is how much energy an object has because of its movement. We can calculate it by taking one half of mass times velocity squared. Another way is to use the equation work equals force times distance, because kinetic and potential energy are equal to work. We found the kinetic energy of the marble on the inclined plane.
Potential Energy- Potential energy is identified as how much energy an object has the potential to generate. It is found by multiplying height, acceleration, and mass. We found the potential energy of the pendulum and of the one kilogram mass.
Mechanical Advantage- This is how much easier a tool or machine makes a task. For example, if the mechanical advantage of a lever was 2, than it would require half as much force to do the task at hand. We found the mechanical energy of the pulley and of the lever that follows the inclined plane.
Toppling- Toppling is a chain reaction that happens when the center of gravity of an object if pushed over the edge of its base. This is the idea behind the dominoes.
Velocity- Velocity is essentially the rate that an object in a specific direction. This is different than speed itself, because speed is simply how fast something is moving.For instance, if someone walks in a circle, they may maintain their speed, but their velocity will be constantly changing. Velocity can be found by dividing the distance covered by the time it took to cover that distance. We found the velocity of the marble in the screw.
In this video, the bottom half actually started a little bit early, but it is the best video we have.
My Relection
The rube goldberg machines were very fun to build with solid wood and nails instead of duct tape and cardboard. My group worked together really well and the presentation was interesting. I learned a few things during the process about myself and about working in groups. One thing I learned about myself working in groups is that I need to explain my ideas better. I found it difficult to communicate some of my plans for steps in the machine. I had to draw everything out so that the other members in my group could understand. Now I know how to communicate better. One example of this during the project was my idea for the pulley. I had a very difficult time explaining it until I drew a diagram and very slowly exlained it. Another helpful tip that I figured out is to be really encouraging, no matter how badly someone has messed up. This helped keep us working together well, because we did our best to stay positive. It was already hard enough when we were all in a good mood, and if we had been angry at each other it would have been nearly impossible. One weakness that I noticed our group had was planning. What I mean by this is that while working on a project, the planning should not be rushed, because although it may seem like a good idea to try to get stuff done right then, it will probably end up taking longer. One example of this in our project was that we used narrow PVC pipes to support the top level at first because they were readily available and there was plenty of it. We ended up wasting almost three of our building days attempting to install them, then decided that it was too unstable, and that it would be worth it to just cut a few pieces of wood to use. That only took us about thirty minutes. If we had planned better, we would have used wood right from the start and not have been so far behind for the rest of the time. Something that we began to do fairly well was dividing tasks. This helped us get a lot more work done. Before we had been having the whole group work on one step, but we realized that the number of people working on a step really didn't speed up the process, because only one person can really be on a step at a time. Once we assigned specific steps to each of us, it noticeably accelerated the process and helped us catch up to the rest of the groups.