Rube Goldberg:The execution of pearie Antoinette
Group:Ben D. LEo Bouncristiani Elise Chassman
If you are wondering what a Rube Goldberg is, I will quickly summarize it. A Rube Goldberg is a machine made of many simple machines (pulleys, inclined planes, wedges, etc.). These machines make a chain reaction leading to doing a simple result at the very end. These usually are rolling dice, pouring water, or in my case, chopping a pear with a guillotine.
The master plan
The first step of any Rube Goldberg tends to be a plan or schematic. We drew out all of our simple machines and steps on a piece of paper. We had trouble coming up with an end result for our Rube Goldberg, we thought and thought till Leo Bouncristiani decided we should make a guillotine. Hence i named our Rube Goldberg The Execution of Pearie Antoinette since our end goal was to cut a pear with a guillotine.Our plan involved 12 steps and 5 simple machines. Over the course of constructing, we had to only adjust some minor parts of our schematics. We decided to add an alternate end result for our Rube Goldberg which was to let a marble hit the spacebar of a computer activating an audio clip of cheering. Now that the time of planning is over, the first steps of construction shall begin.
The construction phase
On the very first day Leo had already constructed his guillotine and all we needed to decide was what materials we needed to build this rube goldberg. On our first day we got to work on our first several steps including the inclined plane and the pulley system. We also added supports to the base of our board to provide stability and the ability to prop it upright. Originally we wanted to nail the inclined plane directly into the board but found that difficult,instead we put nails beneath the plane so we could rest it on top of the nails. The pulley was still not completed at the end of this day.
On the second and third day we focused primarily on the pulley system and the second inclined plane. We attached the pulley above the second inclined plane and added an indentation on the plane to fit a marble in it. The plan was to have the pulley system displace the marble from the indentation. Unfortunately, the pulley system would not hit the marble at all and we had to spend 2 day tweaking it until it worked 90% of the time. We found that we needed more mass on one side of the pulley to have it land more accurately.
During the fourth and fifth days of work we glued a funnel onto the end of our second inclined plane which acts as a screw. This did take half of the fourth day.While Ben and Elise worked on the funnel, Leo and I began work on the lever below the pulley. This part of the rube goldberg was crucial: if it didn't work the two end results wouldn't work either. Leo and I had to balance out both sides and insert the lever. The lever was two sided. One end released a ball that activated the pin of the guillotine which cuts the fruit, and the second catches the marble in a cup and drops it down to continue with the end result.
On the sixth and seventh work days we did tweaking on the lever and proceeded to ad two inclined planes at the end of each side of the lever. This was to allow the ball and marble to continue to other parts of the goldberg. We also added some side guards to prevent the ball falling off the plane (this was only for the inclined plane leading to the guillotine).
During the final days of building the rube goldberg, we only had to finish the second end result which included adding several small inclined planes that resemble something you would see in a pinball machine at the end of the inclined plane leading down to the alternate end result. Ben brought in his computer to play the cheering noise and at first the marble didnt have enough force to press the spacebar. To fix this we added a wood block beneath it to increase surface area in hope that it would work. And so it did.......well....half the time. The construction phase has now been completed and my group moved onto the physics aspect of this deceivingly simple machine.
On the second and third day we focused primarily on the pulley system and the second inclined plane. We attached the pulley above the second inclined plane and added an indentation on the plane to fit a marble in it. The plan was to have the pulley system displace the marble from the indentation. Unfortunately, the pulley system would not hit the marble at all and we had to spend 2 day tweaking it until it worked 90% of the time. We found that we needed more mass on one side of the pulley to have it land more accurately.
During the fourth and fifth days of work we glued a funnel onto the end of our second inclined plane which acts as a screw. This did take half of the fourth day.While Ben and Elise worked on the funnel, Leo and I began work on the lever below the pulley. This part of the rube goldberg was crucial: if it didn't work the two end results wouldn't work either. Leo and I had to balance out both sides and insert the lever. The lever was two sided. One end released a ball that activated the pin of the guillotine which cuts the fruit, and the second catches the marble in a cup and drops it down to continue with the end result.
On the sixth and seventh work days we did tweaking on the lever and proceeded to ad two inclined planes at the end of each side of the lever. This was to allow the ball and marble to continue to other parts of the goldberg. We also added some side guards to prevent the ball falling off the plane (this was only for the inclined plane leading to the guillotine).
During the final days of building the rube goldberg, we only had to finish the second end result which included adding several small inclined planes that resemble something you would see in a pinball machine at the end of the inclined plane leading down to the alternate end result. Ben brought in his computer to play the cheering noise and at first the marble didnt have enough force to press the spacebar. To fix this we added a wood block beneath it to increase surface area in hope that it would work. And so it did.......well....half the time. The construction phase has now been completed and my group moved onto the physics aspect of this deceivingly simple machine.
Behind the scenes:calculations
You may be wondering how physics are involved in a rube goldberg. Well to be honest virtually everything involves physics!
Step 1:Blowing through straw. Well Ben blows through a straw 19 centimeters long to dislodge the marble from the starting point.All we did here was calculate the length of the straw.
Step 2:Inclined plane. The marble rolls down the inclined plane. My group and I calculated the velocity of the marble by dividing the length and the time the ball took to roll down the plane. So we divided .4 meters by .22 seconds and got a velocity of 1.82m/s.
Step 3: Pulley:The ball rolls into the pulley causing it to fall and hit the second marble. First off we decided to measure the force of the pulley. The pulley's mass was .162kg which transfers into .162N of force.
Step 4: Inclined plane....another one. The pulley dislodges another marble down an inclined plane. We calculated the speed of the marble and divided it by the mechanical energy which was the plane length 36cm divided by the height 4cm which gave us a mechanical advantage of 9m/s squared. We divided the speed by the mechanical advantage and got 1.1m/s squared.
Step 5:Funnel...almost half way there! The marble spins around the funnel as if it where a screw. For this one we calculated the mechanical advantage which was 5.14 by dividing the length by the height.
Step 6:Lever:Releases ball to guillotine and marble to alternate end result. In this simple machine we calculated the distance from which the weight is applied 19cm from the distance the weight has moved 16cm we divided 19cm by 16cm giving us an mechanical advantage of 1.187.
Step 7: Inclined plane (guillotine):Ball follows inclined plane to push pin.For this one we decided to find the force it takes to push the pin. Using the formula of F=MA (force=mass x acceleration) The ball weighed 156.2 grams, it took half a second for the ball to strike the pin, length of plane is 45cm and height is 12cm. F=156.2 x 9.8 which leads to F=1530.76 N.....wowza!
Step 8: Inclined plane (alternate end result):Marble from funnel lands in cup on the lever dropping it onto this inclined plane. My group decided to find the potential energy of this step. We found that the plane was 10cm long and 1.5 high. We used formula PE=mgh using data we already know. PE=.0162 x 9.8m/s x .015 which equals a PE of .0023814 Joules.
Step 9:Series of inclined planes: Marble enters a series of inclined planes in a pinball like motion. We calculated these planes as a whole which where roughly 11cm long and 3 cm high. Then we found the mechanical advantage by dividing 11 over 3 which gave us an MA of 3.67.
Step 10:Tube: marble exits the inclined planes into a tube that leads to the spacebar activating the cheering noise. We solved this one for its force and it was 17cm high and 0cm long. using F=MA F=.0162 x 9.8 we got F=.16N
Step 11:Guillotine pulley: Going back to the guillotine area of the goldberg the clip is released by the ball which also releases the pulley That we calculated to have a force of 10 newtons (N)
Step 12:The wedge of doom (wedge not wedgie): The pulley (step 11) releases the wedge which slams down upon the victim killing them instantly. We calculated the mechanical advantage which we found to be a whopping 2200. We found this by measuring the thickness of the wedge .00005m, and the length .11m. We divided the length by the width of the wedge and got 2200.
By now you must be puzzled that there arent any pictures...well i suppose you did read quite a bit (or just scrolled down looking for something colorful) and therefore i reward you with a video of our functioning rube goldberg!
Step 1:Blowing through straw. Well Ben blows through a straw 19 centimeters long to dislodge the marble from the starting point.All we did here was calculate the length of the straw.
Step 2:Inclined plane. The marble rolls down the inclined plane. My group and I calculated the velocity of the marble by dividing the length and the time the ball took to roll down the plane. So we divided .4 meters by .22 seconds and got a velocity of 1.82m/s.
Step 3: Pulley:The ball rolls into the pulley causing it to fall and hit the second marble. First off we decided to measure the force of the pulley. The pulley's mass was .162kg which transfers into .162N of force.
Step 4: Inclined plane....another one. The pulley dislodges another marble down an inclined plane. We calculated the speed of the marble and divided it by the mechanical energy which was the plane length 36cm divided by the height 4cm which gave us a mechanical advantage of 9m/s squared. We divided the speed by the mechanical advantage and got 1.1m/s squared.
Step 5:Funnel...almost half way there! The marble spins around the funnel as if it where a screw. For this one we calculated the mechanical advantage which was 5.14 by dividing the length by the height.
Step 6:Lever:Releases ball to guillotine and marble to alternate end result. In this simple machine we calculated the distance from which the weight is applied 19cm from the distance the weight has moved 16cm we divided 19cm by 16cm giving us an mechanical advantage of 1.187.
Step 7: Inclined plane (guillotine):Ball follows inclined plane to push pin.For this one we decided to find the force it takes to push the pin. Using the formula of F=MA (force=mass x acceleration) The ball weighed 156.2 grams, it took half a second for the ball to strike the pin, length of plane is 45cm and height is 12cm. F=156.2 x 9.8 which leads to F=1530.76 N.....wowza!
Step 8: Inclined plane (alternate end result):Marble from funnel lands in cup on the lever dropping it onto this inclined plane. My group decided to find the potential energy of this step. We found that the plane was 10cm long and 1.5 high. We used formula PE=mgh using data we already know. PE=.0162 x 9.8m/s x .015 which equals a PE of .0023814 Joules.
Step 9:Series of inclined planes: Marble enters a series of inclined planes in a pinball like motion. We calculated these planes as a whole which where roughly 11cm long and 3 cm high. Then we found the mechanical advantage by dividing 11 over 3 which gave us an MA of 3.67.
Step 10:Tube: marble exits the inclined planes into a tube that leads to the spacebar activating the cheering noise. We solved this one for its force and it was 17cm high and 0cm long. using F=MA F=.0162 x 9.8 we got F=.16N
Step 11:Guillotine pulley: Going back to the guillotine area of the goldberg the clip is released by the ball which also releases the pulley That we calculated to have a force of 10 newtons (N)
Step 12:The wedge of doom (wedge not wedgie): The pulley (step 11) releases the wedge which slams down upon the victim killing them instantly. We calculated the mechanical advantage which we found to be a whopping 2200. We found this by measuring the thickness of the wedge .00005m, and the length .11m. We divided the length by the width of the wedge and got 2200.
By now you must be puzzled that there arent any pictures...well i suppose you did read quite a bit (or just scrolled down looking for something colorful) and therefore i reward you with a video of our functioning rube goldberg!
Reflections....like a mirror but not
I never thought that a rube goldberg can teach a person so much about physics....even one that seems as simple as mine is filled with calculations and error at every turn. I appreciate my group (Leo,Elise,and Ben) for doing such a great job working together 95% of the time. In the time I've spent working on this project, I discovered that i work better in groups than i do alone....probably because it is more fun and engaging than doing things alone. I also discovered i am not very bad at presenting in front of crowds (Though i often am nearly scared to death). During presentation night my group and I started off a bit shaky but after each presentation we all improved bit by bit which i found great.I sometimes get off task...occasionally I would wander off and not pay attention to what is happening on our project.This is something I need to work on....oh yet it is fun to see what other groups are doing. I also need to work on leadership skills, on my collaboration rubrics i scored relatively low in that area. I'm often the one who follows...not the one who leads. My groups greatest attributes would definitely be our collaboration and our work ethic nearly all the time. We finished our project before most of the other groups since we all quickly agree on a plan and carry it out step by step as a team. Sometimes we would occasionally branch into pairs and work on two different parts of the goldberg to increase productivity. All in all we find it better to work on something as a team rather than individuals working on multiple concepts or parts. I also noticed we always come up with a solution quickly and effectively if something doesn't go according to plan. Though we had some great moments we also had a few bad ones.
First of all most problems came from the project itself and not from my group. First of all the lever seemed like a great idea.....until after we built it. The hole we inserted it in had too much friction, and the sides of the lever where uneven. If we would have balanced and tested the lever as we built it, there wouldn't have been as many setbacks which took up quite a bit of time. Secondly our alternative end result was a pain since we expected it to work when we planned it but didn't work at all when we put it into action. We spent so much time trying to fix it a certain way instead of trying different ways to solve the problem. This also took up lots of our time. We seemed to have problems when it came to things we did not expect, though we eventually worked around it together. Overall, i never could have asked for a better group.
First of all most problems came from the project itself and not from my group. First of all the lever seemed like a great idea.....until after we built it. The hole we inserted it in had too much friction, and the sides of the lever where uneven. If we would have balanced and tested the lever as we built it, there wouldn't have been as many setbacks which took up quite a bit of time. Secondly our alternative end result was a pain since we expected it to work when we planned it but didn't work at all when we put it into action. We spent so much time trying to fix it a certain way instead of trying different ways to solve the problem. This also took up lots of our time. We seemed to have problems when it came to things we did not expect, though we eventually worked around it together. Overall, i never could have asked for a better group.