A Rube Goldberg machine is a machine that takes a simple task and makes it into a very complicated task. For our Rube Goldberg Machine, my group and I started out with our end product: taking a picture. We made a rough sketch of what we wanted the machine to look like, and started building. We built a screw for our first step, and added a pulley for our second step. The pulley was especially hard, because everyone in my group had a different idea of what we wanted the pulley to do. Eventually we settled on decision, and moved onto our third step. We then put the two boards on top of each other to give us more space and height to work with. We attached the two boards using PVC pipe to hold the top board up. We soon realized though, that the PVC was too unstable to support the board, so we took the pipes off and replaced it with wood. It then became much more steady. As we kept pushing through our build days, we realized we had a lot of difficulties with our machine, because of our lack of planning. One of our biggest issues was the end result; it would be too hard and unrealiable to have a stylus swing down and hit the button on the iPhone. We threw away that idea and changed our end product to stapling a piece of paper. Our 2nd problem was making our hammer stay up and balanced. The block that was holding the hammer was too light, so we added another piece of wood behind the block to give it some more weight. On our bottom level, we had to redo every step, because we had changed our end. We had the most trouble with our dominoes, inclined plane, and lever(see the slideshow to the right). We couldn't get the marble to roll off the inclined plane and hit the lever just right. We also didn't realize that the nail acting as the pivot point for the lever was getting bent every day when we stored the machine. Once we realized this, our lever became much more accurate.
In our machine we had to use 5 of the 6 simple machines. The simple machines are: a screw, a pulley, a wheel and axle, an inclined plane, a lever, and a wedge. My group did not use the wedge. We calculated velocity, speed, mechanical advantage, potential energy, kinetic energy, work, force, and energy transfer of our steps. To see my calculations of each step, see the slideshow above. Overall, I think my group and I worked really well on this project! Our machine worked most of the time, and I had a lot of fun making it. In this project, I learned that if I want something to happen or be done, I have to really speak up. A lot of the time, I would ask a question, and no one would answer, so I learned to ask the question louder and to make sure someone answers. Another skill I learned during the building of this project, was how to operate power tools. I had used a drill before, but it had always been with someone helping me along and keeping a close watch of my every move. During this project, I had to figure it out by myself, which really helped me understand what I was doing with the drill. I had never used a power saw before, but in these past four weeks, I learned how to use one. I really like that in STEM we have a lot of freedom; this means that we also have to figure out a lot of things ourselves. It forces us to use our brains and come up with ideas--instead of having an adult there to hold our hand the whole way. Some things that my group and I could have done better, is our time management and planning. Some days we got almost nothing done, or we spent the whole day on something that should have taken 15 minutes. For example, one day we spent the whole class attaching PVC pipes to the boards to hold up the 2 levels. We spent so much time on this part of our machine, but ended up taking it off because they were too unstable. Another thing that we should work on is our planning. We didn't plan out our machine, and started building our Rube Goldberg, with only a vague idea of what we wanted. This led to a lot of setbacks in our design. For example, we had originally wanted our end result to be taking a picture, but we realized in the middle of our 4 weeks, that this was going to be very hard to accomplish. For my future projects, I will use the time I am given to get things done, and I will be sure to plan things out before starting.
Here are the concepts that we used: Velocity: the rate of distance covered in a direction Mechanical Advantage: how much easier a machine makes a task Work: the amount of energy put into something Kinetic Energy: energy due to motion Potential Energy: energy an object has due to its position at a height or in a gravitational field Speed: the rate at which something is able to operate Downward Force/Gravity: the force that pulls an object downward towards the center of the earth or to any other physical body having mass
Here are the steps of our machine and the physics we calculated: 1.The marble rolls down the screw - acceleration due to gravity, velocity 2.The big marble falls in the cup and pulls up on block of wood on the other side - mechanical advantage 3.The hammer falls and hits another marble - energy transfer=work 4. The marble rolls down the inclined plane - kinetic energy 5. The marble hits the lever and the lever hits the dominoes - ideal mechanical advantage 6. The dominoes fall over - toppling due to gravity 7. The dominoes start the pendulum - potential energy 8. The pendulum hits the cup which has a car under it - speed 9. The car hits the string of weights - downward force 10. The big weight falls onto the stapler - potential energy