Rube Goldberg Machine

Step 9

The machine was done and ready for presenting! To zip a zipper, the user must first cut a string under tension with scissors, a wedge (two inclined planes shoved together to cut a material). The tension is released, and the button to activate the "catapult" was pressed. That activated a lever which would release a marble down the track. After the marble went through some simple machines, it fell into a ketchup cup attached to a weight on the edge of the table. The marble caused the weight to fall off the table. The weight was attached to a string, which was wound around the pulley, which zipped the zipper!

Step 4

Step 6

I also got a zipper for the group to use for the objective. The zipper mount was first blueprinted and constructed using fence boards left over from the birdhouse project. I hammered nails through the zipper into the upright piece of the mount, but they didn't go in all the way. The zipper was pulled out slightly to make it a bit easier to zip. Meanwhile, a teammate made a pulley (A wheel with a string around it to make lifting easier), a wheel with string wrapped around it to make lifting easier, and a mount for the pulley. The pulley mount was mounted onto the zipper mount. A string was then wrapped around the pulley to complete the assembly.

Step 5

Even more problems resulted from my rubber band fix. The catapult arm would now lift up properly, but it wouldn't go down all the way because the motor couldn't fight the power of the rubber band! Not only that, but it STILL wouldn't catapult! To fix the lifting problem, I had to reprogram the RCX to drive the motor backwards when it was resetting the arm. For debugging purposes, I also made it beep when the switch was pressed. It didn't work perfect, but it did what it needed to. Now that this is done, I took my design into class.

In my opinion, my major contribution to the group was my should-have-been catapult. The big Lego catapult went through about 4 to 5 designs before the final version was done. It is powered my a Lego Mindstorms RCX, which, if the sensor attached to it is triggered, will turn on a motor to make a leverage arm attached to the motor turn. This in turn would make the lever rotate along it's end. To my disappointment, the Lego "E" motor I used had very very little turning power, and it wouldn't catapult things, let alone lift the catapult lever itself! A lever is an arm that rotates around a point. To fix the lifting problem, I attached a Lego rubber band to the leverage arm and the catapult arm.

Step 3

A bit more understanding of the simple machines and energy was needed! I already knew that Kinetic Energy is energy in motion, a ball falling onto your foot. I also knew that Potential Energy is stored energy, someone holding a ball above your foot. It has the potential to become kinetic energy if the person lets go of the ball. Once I knew what I was doing, I got to work.

Step 7

Meanwhile, some of my group helped me, but some worked on the marble run portion of the machine. The marble run pieces included a wheel and axle, and many inclined planes and screws. A wheel and axle is a circle that revolves around a center point, like the wheels in a car. A screw is an inclined plane wrapped around a cylinder. In the case of this project, a swirly-motion of an object was fine. An inclined plane is a slope.

Step 1

Step 2

The only requirements for our machine were to use a minimum of all six simple machines, and in the end, to zip a zipper. The pulley, inclined plane, wedge, screw, wheel and axle, and lever. My team (Group Delta) went to work thinking up ideas for our machine. We then took a few ideas from each team member to create our plan. In the end, the idea board was just a basic guide, and not all of the ideas were used.

Here is another construction project!!! This time, we made a Rube Goldberg Machine (A really complex way to perform a simple task)! The entire thing can demonstrate Newton's 3rd Law of Motion (For every action, there is an equal and opposite reaction.) We first were put into teams of four. For the first step, we took a peek at what we got, which was JUST a box! Everything else was supplied by either the scrap box, or ourselves! This wasn't a problem at all, as my team was very creative and had cool stuff at home.

Rube Goldberg Machines

David Goar

Period 4

Step 10

Step 8

The few days before the day in which we would present our machine we started running into a few problems. First off, after days of being turned on, my catapult was running low on battery power. I replaced the batteries the next day, however it wasn't that simple. Warning: geek mode activated - all programs on the RCX are stored in it's RAM memory, which, if it loses power at any time, will be deleted (requires re-download of firmware and any programs that were on it, but I fixed this the same night). Also, the weight getting knocked off the table by the marble was pretty inconsistent. After a few ideas were thrown around, our group glued a ketchup cup onto the weight for the marble to land in. For the most part, this worked!

In the end, team Delta got a 98%, really good! However to get that really good grade, a few ideas, marble run tracks, and hot wheels cars needed to be dropped from the original plan we made.

* One idea was to have the start be a Hot Wheels car that rolled down a track to hit the "catapult" button.

* Another idea was to use a round piece of plastic from the scrap box as our wheel, and have it roll along a track, the wheel supported by a dowel (axle). The track was slightly difficult to make and mount, and the wheel was hard to get to start moving.

* Our first attempt at zipping the zipper involved marbles falling into a box to pull the zipper up. The marbles proved to be too light-weight, and we used the weight we used in the final design.