Rube Goldberg Machine
The first project our class worked on was the Rube Goldberg Machine. Our group's project was themed as a trap for the famous cartoon character, road runner. The members in my group were Emma Rice, Tanner Spence, and Sam Scolvick. The story and description behind our project was that we were helping Wile E. Coyote to trap and kill the road runner. This was supposedly done using a machine that only took seven seconds to operate. This would ensure that the road runner was killed once and for all, but, like always, Wile E.'s trap fails and ends up crushing him under a boulder. In this project, many factors of physics and engineering were used, including concepts of physics and simple machines. The concepts and simple machines we used in our RG Machine are listed below.
Physics Concepts Used:
- Mechanical Advantage - Mechanical Advantage is the number of times easier (IE. 4x or 5x easier) it is to accomplish a task using a mechanism. We used mechanical advantage in almost all of our simple machines to make difficult tasks easier.
- Acceleration - Acceleration is the change in speed something has in a certain period of time. The balls accelerated when they went down the ramps and when they went through the spiral.
- Force - Force is the energy applied on impact between two objects. Force was applied on our Rube Goldberg Machine all over through-out the whole project. Some examples of these forces are when two balls collided and the Earth's gravity pulling down on the balls so they would push down against the inclined planes and roll.
- Velocity - Velocity is the speed and direction that something or someone is moving. Some examples of velocity are when the ball is on the straight plane. It ideally is moving at a constant speed and direction, with no acceleration if friction was not accounted for.
- Gravity - The pull Earth has on objects that causes them to accelerate towards the planet. Gravity causes objects to accelerate downward at 9.8 meters per second squared.
- Mass -
Simple Machines Used:
- Pulley - One of our most important simple machines was a pulley, used to lift objects by running a string or rope over a wheel and applying force to one side, lifting the load on the other. In our case, the force applied was the car landing in a cup, pulling the string downward and tilting a board, causing a ball to begin rolling down it.
- Incline Plane - Easily our most used simple machine, the incline plane is a tilted board using gravity to move an object. The steeper the incline is, the faster the ball will accelerate and vice versa. The reason this happens is because when a board is flat, the ball is being pulled straight into it, and no work is done, but when it is tilted, the ball is pulled straight down into the angle of the plane and is forced along with it's direction.
- Spiral - A spiral is a tube wrapped around itself in a circular, downward path. An example of this is a spring or slinky. This works like an incline plane in the way that it moves an object using gravity, but a spiral is a much more vertical based movement, rather than the incline plane's mainly horizontal movement.
- Lever - A lever is a bar that rotates on an axis, or pivot, so that when force is applied to one side, the bar rotates and raises one side while lowering the other. In our machine, our lever was secured by a nail and rotated when a marble fell off of an incline plane and applied a force to one side of the lever. On the opposite side, there was a ball balanced on the bar, so when it is rotated, the ball would roll off onto an incline plane.
- Wedge - A wedge is any point made by at least two flat planes used to split something or hold it in place. In our project, the wedge was used to hold the car in place to stop it from moving until we moved it. This was meant to give us a more consistent run so that the forces were never changed through human error, including putting the car on the wrong spot on the incline plane or using too much force when pushing the car down the ramp.
While doing this project, I had many things I was proud of, and some I was not so proud of. One example of one of my proud achievements in this project was that I learned to have a better work ethic, causing me to get a better collaboration rubric score. Another example is when my group was trying to decide how to make the pulley work and I pitched the idea of using the whole board as a movable platform, which ended up making it into the final draft. Though both of these are good changes I made to myself and my group, there were some mistakes along the way. When we were almost completely done with our project, I began to paint but through poor communication I misheard the color scheme and painted the wrong colors, which taught me to communicate better with my group members. Another mistake I made during the creation of our Rube Goldberg machine was that while screwing in the base, I put them way too high so it tipped over. Because of this, work was postponed so we could reapply the base. This taught me that I should think twice before I begin work. Overall, this presentation was a major learning experience.
Physics of Sports Video
During this project, my group and I made a video explaining the physics of a certain action in a sport of our choosing. The sport we chose was basketball and the action chosen was shooting a three pointer. We had to calculate different concepts of physics present in shooting a three pointer, including force of impact, velocity of the ball, and angling to get the shot just right. Below are the concepts that we used in this project:
- Force of Impact: The force of impact is the force at which two objects collide.
- Momentum: The difficulty at which an item would be to stop because of it's push to continue moving.
- Impulse: The length in time and force used to push an object.
- Vertical Velocity: The distance covered on the vertical (y) direction or plane in a specific amount of time.
- Horizontal Velocity: The distance covered on the horizontal (x) direction or plane in a specified amount of time.
- Total Velocity: The total diagonal and vertical distance together during a certain amount of time.
Reflection: Reflecting on how well I did on this project, there were some moments where I truly shined, and some where I was not as bright. One example of a shining moment from me was that I organized the whole team together and knew what we needed to do and when fairly well throughout the creation of the video. Another, is that I kept the team focused throughout most of the shooting and editing of the video. This brings us to our negatives throughout the project. One negative I had during this project was that once in a while on shooting days, when I was shooting hoops, I would get distracted and stop taking my time on the three pointers. This required us to re-shoot the video a couple of times, and it taught me to always stay on track and focus on the task at hand. Another negative effect I had was on the voice-overs, when I would occasionally begin talking and mess up the whole recording, which taught me to always wait until an appropriate time to speak and interact with people. This lesson has taught me many life lessons and valuable skills.
Our First Draft Video
Our Final Draft Video
Note that we included more of the physics work, which we used to calculate the perfect shot, and added subtitles for more visual representation of our words in our final draft.
Fire Away!
Our Trebuchet has a black, wooden arm held up and rotating on a PVC pipe with a two centimeter diameter, which is held up by two arms that attach to the trebuchet’s wood base. There are three pairs of two knotted rubber bands wrapped around the base on one side and around a nail on the arm on the other, which applies the force needed to launch our projectile. Our projectile is a clay ball molded around an eight centimeter string, and is hooked onto a nail so that when the arm launches it, it unhooks and flings at maximum momentum, therefore maximum distance.
To try to improve the firing distance of our trebuchet, we made eight modifications that my fellow classmates proved to increase the efficiency of our class trebuchets. The eight modifications we made were:
- We made the projectile almost exactly ten grams because this was shown as the perfect inbetween of too heavy and too light. If the projectile was too light, it would be inaccurate and would not go very far, and if it was too heavy, it would have fallen to the ground faster due to its weight and, therefore, would not make it as far.
- We made the string exactly 8 cm long because this was shown to give the most momentum and be the most accurate of all the string lengths.
- My group and I made the hook nail that the ball and string attaches to a 60 degree angle because this was shown to launch the ball at its maximum height and momentum, causing it to be fired farther than a straight nailed trebuchet.
- Another modification we made was keeping the base sturdy because if the base is not sturdy, it is easier for the trebuchet to break or come apart during firing or when loading the projectile.
- We made the base flat with no wheels so that it would not move during firing because this was proven to increase the distance that the ball fired from the trebuchet.
- We made our trebuchet with no stopper because one group proved it to increase the firing range of their trebuchet, so we decided to try it on ours.
- We also kept the legs spaced out because it was proven to be more effective than having them close together.
- We also changed the amount of rubber bands to six because that is supposed to give the perfect medium of accuracy and distance.
To try to improve our trebuchet, my group and I tested where on the base the rubber bands give the most pull. It is uncertain whether or not the positioning of the rubber bands affects the launch in any way. To test our theory of rubber band position affecting launch distance, we used some rubber bands and continued to move them to different spots on the base and fired the trebuchet. What we got from this was four different positions’ averages. When the rubber bands were 10 cm from the axle, the average distance was 19m, when they were 12 cm off it was also an average of 19m, when they were 14 cm off, the average was 15m, and when the bands were behind the axle by 5 cm, the average distance was 17m. The problem with this data is that there is no best average distance since there are two equal averages. The furthest our projectile went was 22m and it fired this far from 10 cm, 14 cm, and -5 cm. The only problem with this data is that because it goes the maximum distance in three of the four different positions, we can’t tell which one actually fired it the furthest.
Below are the technical specifications of our trebuchet:
- Mass of Projectile = 10g
- Distance Horizontal = 25m
- Time in Air = 2.6 seconds
- Vertical Distance = 30m
- Velocity Horizontal = 10 m/s
- Velocity Vertical = 12.25 m/s
- Velocity Total = 15.81 m/s
- Spring Constant = .00392 N/m
- Potential Energy of Spring = 3.61J
- Kinetic Energy of Ball = 1.25J
- Percent of Energy Converted = 35%
- Angle of Release = 45-50 Degrees
Our Trebuchet is able to fire up to twenty-five feet, and can shoot up to thirty feet vertically. It is fairly small and not incredibly heavy, so it is mobile as well. It has a very simple design, which means it would not be very expensive to build.
Move it - Hybrid Car
The Move It project was one pitched by the popular car company Hyundai, in which the S.T.E.M Marin students had to create a prototype for an alternative energy vehicle. So, we each had to create a vehicle that could move five meters using some other method, preferably a more economic one, than the conventional, gas powered motor that cars use. We would need to keep two "people" alive, which were shown as two rolls of pennies, and if they broke the passengers "died." The purpose of this activity is to be creative, but at the same time simple, so your vehicle isn't too costly to build. This teaches us that some of the most inventive ideas can be some of the most simple. There were many different vehicle ideas in the class including some that run off of solar power, tension(or rubber band) powered, and even some vehicles that were propelled by ramps.
For my group's vehicle, we used a ramp propelled vehicle. It had a rectangular frame an a base, with three wood pillars holding up a T shaped roof. The T shaped roof was used to hold the penny rolls in place by firmly strapping them to the bottom of the T. Two of the wheels were PVC pipe with a wood cylinder filling the center of the pipe. These wheels had a metal axle holding them to the car and turning them when the car moved. The front wheel was a small, golf ball sized whiffle ball with a wood axle holding it in place and letting it rotate. Because of the ball wheel we named our car the Ball.
For the first meter that our car drove, the velocity is 2.2 m/s. The second meter is 1.82 m/s. Third is 1.35 m/s. Fourth is 1.02 m/s. And the last meter is 0.43 m/s. The velocity slowly decreases as the number of meters traveled increases because the friction between the ground and the wheels slows the car down and causes it to stop, which means the kinetic energy was transferred into thermal energy. The car’s potential energy is 3.18 Joules when it is on the ramp, and when it reaches the bottom, the potential energy becomes 0.
During this project, I believe that I worked fairly well over all. When my group members finished the section of the vehicle they were working on, I believe that I did a good job at helping them find another task to complete to help perfect our vehicle. I also helped pitch ideas for what our vehicle would look like, and many of the ideas made it through to the final draft. Though I did many great things during this project, there were some time when I got upset with my group and/or stopped working for a few minutes, but eventually continued work. Overall I believe I worked well on this project.
For my group's vehicle, we used a ramp propelled vehicle. It had a rectangular frame an a base, with three wood pillars holding up a T shaped roof. The T shaped roof was used to hold the penny rolls in place by firmly strapping them to the bottom of the T. Two of the wheels were PVC pipe with a wood cylinder filling the center of the pipe. These wheels had a metal axle holding them to the car and turning them when the car moved. The front wheel was a small, golf ball sized whiffle ball with a wood axle holding it in place and letting it rotate. Because of the ball wheel we named our car the Ball.
For the first meter that our car drove, the velocity is 2.2 m/s. The second meter is 1.82 m/s. Third is 1.35 m/s. Fourth is 1.02 m/s. And the last meter is 0.43 m/s. The velocity slowly decreases as the number of meters traveled increases because the friction between the ground and the wheels slows the car down and causes it to stop, which means the kinetic energy was transferred into thermal energy. The car’s potential energy is 3.18 Joules when it is on the ramp, and when it reaches the bottom, the potential energy becomes 0.
During this project, I believe that I worked fairly well over all. When my group members finished the section of the vehicle they were working on, I believe that I did a good job at helping them find another task to complete to help perfect our vehicle. I also helped pitch ideas for what our vehicle would look like, and many of the ideas made it through to the final draft. Though I did many great things during this project, there were some time when I got upset with my group and/or stopped working for a few minutes, but eventually continued work. Overall I believe I worked well on this project.