Rube Goldberg Machine
What is a Rube Goldberg Machine? A Rube Goldberg Machine is a complex machine that accomplishes a very basic task. The original idea of such a task was sketched up by a 1950's cartoonist named Rube Goldberg. He illustrated a very elaborate machine to wipe his face with a napkin after taking a sip of soup.
Our Task
My group chose our main theme of our Rube Goldberg Machine to be cars. We chose cars as our theme because we thought it would be interesting to do for a Rube Goldberg Machine and because cars are fast and have many parts that we can represent throughout our board. To help represent our theme we added cars at the beginning and end, a screw to represent a car doing donuts, and a slow wheel and axle to represent a car wheel doing a burnout.
Our Final Project
Our final project consisted of 10 steps with the final step causing cars race down a track and raise a checkered flag. One main principle of physics that we used throughout our whole project was gravity. In our project something is always going down and without gravity none of the steps for our project would work. We had five simple machines in our project being an inclined plane, a screw, a lever, a wheel and axle, and finally a pulley that is not shown in our video from the camera angle because it is underneath our racetrack with the cars causing them to start their race.
Physics Concepts in Our Project
Velocity - the rate of distance covered in a direction. We calculated this in our marble step when it goes down the tube by taking the change in distance over the change in time and we got a velocity of 9.2m/s²
Mechanical Advantage Ideal - how much further or more distance you have to push due to using the tool. We calculated our Ideal Mechanical Advantage for our wheel and axle we divided the radius of the wheel over the radius of the axle and got a Ideal Mechanical Advantage of 13.5.
Potential Energy - energy of an object due to its position. We calculated the potential energy of our truck in our first step by taking its mass multiplied by its height and acceleration due to gravity to obtain that the car had 7.4 J of potential energy.
Kinetic Energy - energy due to motion. We calculated the trucks kinetic energy after the top of the screw to be 0 J, but at the end to be 4.1 J by multiplying 1/2 by our mass times velocity squared.
Force - push or pull of an object. We calculated the force of the marble hitting the wood by multiplying the marbles mass by its weight to get a force of 0.45 N
Acceleration - rate of change of velocity. We calculated the acceleration of our cars at the end by taking our cars change in velocity divided by the change in time giving us a velocity of 9.8m/s²
Acceleration due to Gravity - energy an object has due to its position in a gravitational field. Gravity is calculated by 9.8m/s² so if our machines all had a mechanical advantage of 0 the velocity of all our steps would be the same at 9.8m/s²
Simple Machines - basic mechanical devices for applying a force. In our project we used an inclined plane, a screw, a lever, a wheel and axle, and finally a pulley
Reflection
I feel I did a pretty good job of contributing to the project. I mainly contributed by building the project and doing problem solving for it. One example of problem solving and building the project was shown by myself in the end of our time period working together as a group. We were puzzled on how to trigger our final step by having the cars race down the track. I decided we could tie a string below the race track and have it pull on the release mechanism to release the cars to race. I also attached a weight to this string put this through the underside of a pulley and put it in the tube. Due to the weight going through the under side of the pulley and back up. the weight wanted to go down and release the cars but it couldn't because of the tube not allowing it to go down. However, when the marble has a collision with the weight it hits it out causing the string to be pulled down releasing the cars.
While I had my strengths in the project, there were a few areas of improvement for myself. One area that I didn't help my group with that much was the calculations of the project because we had two designated people doing that already. I also could have given my group more tools to help practice more for our presentation night.
Overall, it was very fun and was my very first STEM project at San Marin.