Our Rube Goldberg machine was only a distant idea on the first day, when we started brainstorming. We drew a random, last minute drawing, just because we were running out of time; the class period was almost over. Who knew that image we drew would be almost identical to our final outcome? Of course we ended up making a few slight tweaks and changes, but nothing drastic.
Our original design was lacking many essential energy transfers and steps. Looking back at our original illustration, I’m not exactly sure how we thought our machine was going to work, based off of the insufficient drawing we created. Our project starts with two steal balls rolling out of a cup and down several ramps. At first we used only one small marble on this step, but we realized that it was not heavy enough. We tried using five or six of these marbles, but they ended up bumping into each other and the walls, and bouncing out of the whole machine. We borrowed some clay from the group next to us, to try to cover the holes created where pieces of wood met. We concluded that using all of these marbles just gave is an inconsistent outcome. Luckily, we found the two steal balls that worked perfectly with the layout of our project.
After the balls roll down the ramps, the are supposed to drop into a cup, which will give the cup weight, causing the pulley to take action. We had lots of trouble with this step, because the balls would always hit the strings of the pulley and not fall in the cup The balls would also sometimes roll past the cup. We nailed a piece of wood behind the cup so that the balls would not roll out, and we also used popsicle sticks to hold the strings out of the way, so the balls would easily roll right into the cup. Before the balls rolled into the cup, we had to be sure that the cup was filled with just enough weights, that when the balls rolled in, it would be just heavy enough to work.
The pulley caused bb pellets to roll into a funnel, and through a tube. This step was also very troublesome, because we were not sure which size bb’s would work best. If we used to many. or bb’s of to large of size, they would just get clogged inside of the funnel. We had to cut the narrow part of the funnel, giving more space for the bb’s to roll through. We found that a small amount of the bigger size bb’s worked best. When the bb’s rolled through the twisting tube, the would often get stuck at places in the tube that were too steep for the bb’s to roll through. This was easily fixed through slight adjustments in the tube layout.
The bb’s exit the tube into a little truck, that rolls down a ramp after it is given weight, by filling up with bb’s. The bb’s never seemed to land perfectly into the truck, and would always shoot right off of our project. This step required many adjustments. We ended up adding a little cup that they roll into, causing it to shoot down because of the weight. This causes the truck to roll down a track and into a little bucket.
After the truck rolls into the bucket, a pulley system is activated. The only problem we faced on this step was placing enough weight inside the bucket, prior to the arrival of the truck. We experimented, putting different objects in the bucket , until we found the one that worked perfectly.
When the bucket is weighed down, the pulley system pulls a cup forward, releasing crickets into the cage. Our objective is to feed a leopard gecko crickets, so we made our theme very forestry with lots of nature added on to our project as decoration. We used fake, plastic leaves, as well as real leaves which we retrieved from outside. I am hoping that by the Rube Goldberg night that our leaves are not all dead.
This is Ethan's gecko, Jet. The objective for our Rube Goldberg project was to feed him a cricket. On the night that we presented our project, he ate very well. Jet got to eat a cricket every time that our project worked successfully (which was most of the time).
This was our project on day one of building. It's crazy to think of how far we have gone in such a short amount of time.
We began to put all of the general steps on our project. We also painted it.
Concepts of our Machine Inclined plane- A plane inclined at a horizontal angle Pulley- A wheel with a groved rim which changes the direction of a cord Lever- A rigid bar that moves about a pivot Screw- A screw is similar to an inclined plane with the exception of its cylindrical shape Wheel and Axle- a cylindrical shape and shaft that are joined to provide mechanical advantage
copy and paste the following link to watch our machine in action:
This project has taught me many many things. I have gotten better at finding the force, mechanical advantage, and work of things. I have also gotten better at collaborating with others to create. My group worked very well together. We worked very efficiently and we were always on task. I learned a lot about my group mates, and I also learned a lot from them. By creating the Rube Goldberg Machine, I learned how to use power tools, and this project also gave me a better idea about how things work, so to speak.