Rube Goldberg Machine

What is a Rube Goldberg Machine?

A Rube Goldberg machine is an apparatus that includes a complicated series of events and its goal is to achieve a simple task. Each step leads to the next one, performing a chain reaction, until the last step and ending task is accomplished. The first machine was invented and named after a man named Rube Goldberg, an American cartoonist and inventor.

Simple Machines

We included all of these simple machines throughout our project:

• inclined plane
• pulley
• lever
• wedge
• wheel and axle
• screw

Physics and Calculations

To find and calculate for the physics of our simple machines, we used the following equations:

• acceleration- change of velocity/change of time
• force- (mass)(acceleration)
• mechanical advantage- distance of effort/distance of load
• work- (force)(distance)
• velocity- change of distance/change of time

Velocity

Velocity is the rate of covered distance in a direction. Since it is a vector quantity, it includes magnitude and direction. In my project, one of the steps I calculated the velocity of was a ramp. I first measured how long the ramp was, then timed how long it took the ball to roll down it. The ramp was 0.58 meters long and it took the ball 1.26 seconds to roll down it. I substituted these numbers into the formula for velocity (change of distance/change of time) and ended up finding that the ball rolled down the ramp with an average velocity of 0.46 meters per second.

Acceleration

Acceleration is the rate of change of velocity, which means how much the object is speeding up or slowing down. In our machine, I calculated the acceleration of a marble down a ramp. I first found the ramp's length and height. The length was 43 centimeters and the height was 8 centimeters. I divided the length by the height to get an answer of 5.4. I then divided 9.8 meters per seconds squared (which is the acceleration due to gravity) by 5.4. I ended up finding that that the acceleration was 1.8 meters per seconds squared. This is another method of finding acceleration besides the basic formula of change of velocity/change of time.

Force

Force is the push or pull on an object, and causes a change in motion. I calculated the force of our marble falling into our pulley cup. What I first did is I weighed the marble and found that its mass was 0.0057 kilograms. Since the marble free falls into the cup, I know that its acceleration is 9.8 meters per seconds squared. (This is the acceleration due to gravity). I substituted these numbers into the formula for force, which is (mass)(acceleration), and calculated a force of 0.05 newtons.

Mechanical Advantage

There are two different types of mechanical advantage. Mechanical advantage real is how much easier a tool makes a task or how much less force you have to put in. This can be calculated by dividing the force the load exerts by the force of the effort being put in. The other type is mechanical advantage ideal. This is how much further, or more distance you have to push due to using a tool. To find this value, you divide the distance of the effort being put in by the distance of the load. Since mechanical advantage is a ratio, units are not used. I used the equation for mechanical advantage ideal to find the mechanical advantage of our wedge (a toy car with a sharp nail attached). I measured and found that the distance of the effort was 0.006 meters and the distance of the load was 0.003 meters. After I divided these numbers, I was able to find that the wedge had a mechanical advantage of 2.

Work

Work is the amount of energy put into doing something. I decided to calculate the work of when a marble hits our toy car (wedge), allowing it to start to roll. First, I had to calculate a force. I did this by using the formula for force I already knew which is (mass)(acceleration). I found the mass of the marble, which was 0.0166 kilograms and multiplied it by the acceleration due to gravity (9.8 meters per second squared) because the marble free falls. I got a product of 0.16 newtons. Now I was ready to plug this number into the equation for work along with the distance the marble travels before hitting the car. The distance was 0.03 meters. So, I multiplied 0.16 newtons and 0.03 meters and ended up finding that the work was 0.0048 joules.

Energy

There are two main types of energy, potential and kinetic. Potential energy is the energy an object has due to its position at a height or in a gravitational field. Kinetic energy is the energy due to motion. Potential energy and kinetic energy equal each other and are the same. The formula is mass of the object, multiplied by acceleration due to gravity, multiplied by its height. Potential energy is when the ball hasn't fallen yet. The higher the object, the higher amount of potential energy there is. Another way to calculate for kinetic energy is multiplying the mass of the object by 1/2 and then multiplying that by the velocity of the falling object squared. An object has the most kinetic energy right before it hits the ground (when the potential energy is 0). I wanted to find the kinetic energy of a marble that rolls down a ramp to then run into a larger marble waiting at the end. I found that the mass of the small marble was 0.0083 kilograms. I also found the velocity the marble has as it traveled down the ramp. The velocity was 0.92 meters per second squared. I multiplied these values together and multiplied that product by 1/2 to give me my final answer. The small marble had a kinetic energy of 0.003 joules. Another step I took was to find that when the small marble hits the large one, a semi-elastic collision occurs. This means almost all the kinetic energy from the small marble was transferred to the larger marble.

Our blueprint of our machine is shown below. We definitely made changes from our original plan and blueprint of our project to improve the quality and effectiveness of it while we worked on this project, but this is our final outline:

Shown below is our construction log. It shows the progress we made over the course of the time we had to complete our Rube Goldberg project:

Reflection

Looking back at our first project of the year, I can definitely say that some things went very well and some did not. Some things I know I could have done better was take more control on some things, but also take less in some. For example, I could've taken more leadership when it came to building our project. And I could've taken less leadership on the calculation and presentation aspects. Playing a more active part in building and a little less active part in the physics and presentation work would be an improvement.

But reflecting on this project, I can see that it allowed me to do a lot of things I don't normally do or haven't done before. I previously did not have a lot of experience with construction aspects such as drilling, sanding, and sawing. But over the course of our building time, I was able to learn and take part in executing these new skills. This project also increased my knowledge and understanding of physics and certain calculations. Being able to repeatedly practice and apply the physics formulas to real life and hands on things really helped me. I believe it helped me grow as a student.

I also think I was able to grow as a team member. Working with two other group mates on a challenging project for four weeks really made me feel that my collaboration skills improved. It wasn't always easy, but it overall did help me (and my team mates) become better collaborators.

My group members and I were able to divide the work well. When it came to painting and decorating, we let our most artistic team mate take the lead while we worked on another part of the project. We did the same for construction. Our member with experience with building took the lead while, similarly, I took the lead on calculating and working on the presentation. Splitting our work this way allowed us to be very efficient. We managed our time very well and did not feel too much stress towards the deadline date because of this.

My group and I all felt that our presentation ran smoothly and overall went very well. Since we had rehearsed many times and performed practice presentations, we were well prepared and all set to showcase our project in front of many judges, parents, and other spectators. Our machine worked every time and this, along with our presentation, made for impressed judges and happy parents. Also, since our project was brightly painted and greatly decorated, we were able to receive some very excited reactions from the young children who watched. It was very pleasing to not only watch our hard work run smoothly, but bode so well with our audience.

Overall, I would say this project was definitely a learning experience. It truly expanded my knowledge and deepened my understanding on several aspects we worked on throughout the course of this project. I can definitely say that I feel better prepared and skilled for the next project. Obviously there are things that could've gone better and things I can improve on in the future, but i'm very proud of my group, our work, and our success.