Our first project as part of STEM Marin was to build a Rube Goldberg machine for a small group of judges. A Rube Goldberg machine is an overly complicated machine built to accomplish a very simple task. The team was given 3 planning days, 9 building days , and 3 presentation days to pull the project together. The machine starts with a marble going down a screw and jumping a ramp that leads to a Newtons Cradle. On the other side of the Newton's Cradle is a Nerf ball which gets hit down a ramp into a cup that is suspended by a pulley. The pulley then pulls a wedge that is holding back a car and the car rolls down another ramp.. Next, the car pulls down a cup and a cup on the corresponding side hits a lever that knocks over a marble into a tube that leads to two ramps. In the last two steps, the marble goes down a long ramp and knocks over a cup holding the weights that pulls the curtain across a rod. The name of our machine was Newton's Fourth Law.
Construction log We spent our first build day picking out the boards that we needed for our frame and the large pieces of wood that we could get out of the shed. On the second day we designed and measured out how much space we had and if we had to change anything from our original schematic . The next couple days were spent working on our scaffolding and stabilization. At first we were going to put the scaffolding on the front, but later, we decided to move it to the back. After that, we put on our inclined planes, ramps, and pulleys. On day 6, we painted and put on the removable parts of the machine..that last two days were putting up the curtain and testing the machine.
Original vs. New Schematic Our first change in our design was instead of using a DIY wheel and axle w used a toy car because its smaller and could fit in the cup easier. Our second change was a big one. Originally we were going to have a big ramp at the beginning. but when it wouldn't work, we changed it to a second class lever so when a cup hit one side it hit the lever and knocked the marble over into our next change. After the marble comes off the lever it was supposed to fall into a funnel but the funnel we got was to big so we instead made it fall into a tube and a cup . In our original schematic we didnt have an ending so after a while we decided on a type of see saw ending so when the marble hit the see saw it knocked the cup over and pulled the curtain across.
Formulas
We used multiple formulas when putting together our machine
Force:Force is how hard something is hitting something. We used force in many parts of the machine including the marble hitting the newtons cradle, the newton cradle hitting the nerf ball,the second pulley hitting the second class lever,and the marble hitting the see saw at the end. You solve for force by doing mass times acceleration.
Mechanical Advantage: Mechanical advantage is how many times easier it is to do something. It is used in our screw at the beginning, all of our ramps, and our pulleys. The formula for MA is force with the machine over force without the machine
Potential Energy: Potential Energy is energy an object has due to its height and position in a gravitational field. This is used in our machine in places like in our screw,any time something goes down a ramp,or ending, and our pulleys.The formula for potential energy is mass times acceleration due to gravity times height.
Things we could improve on
Next time we could improve on making a more realistic first schematic which means scaling better.Next we need to spread our work out more in between each other .Lastly we could have done our presentation a little more smoothly.
Things I learned
With this project i learned how to work better in a group,manage time,and how to use power tools to an extent.Obviously some things didn't go perfectly like we couldn't get it to work 100% of the time,it wasn't a perfect looking machine,and our presentation wasn't great.Lastly I learned that maybe next time i work with a group i should let others share before we do what i say because from feedback i got apparently i don't hear others out.