Rube Goldberg Machine
BEFORE READING THIS OR ANY OTHER ARTICLE ON MY PROJECTS: GO TO THE "ALL ABOUT PHYSICS PAGE"
What is a Rube Goldberg?
First of all, Rube Goldberg was a cartoonist, famous for his depictions of overly-complicated machines designed to perform a simple task. These machines became known as ¨Rube Goldberg Machines¨. Rube Goldberg Machines are contradictions to Ockham's Razor, which states that the only answer to a problem is the simplest one. Instead, Rube Goldberg Machines display the most complex, convoluted solution to a simple task.
What was our task, as STEM students?
Our task was to create a Rube Goldberg Machine to perform any simple task, so long as it fit the following requirements:
- Must be no more than 1*1*0.75 meters
- Minimum of 5 simple machines
- Minimum of 10 steps
- Minimum of 4 energy transfers
- Completes a simple task
All about my project:
My project incorporates all of the simple machines and 10 steps, as shown in the video above. First, I will explain the steps.
Step One: Inclined Plane 1
The first step incorporates the simplest simple machine: the inclined plane. An inclined plane is a slope that allows masses to be raised or lowered a certain height with less work required. We used this simple machine to get the ball rolling, so to speak. Our first inclined plane had a vertical leg of 24.5 cm, a horizontal leg of 54 cm, and a hypotenuse of 59.5 cm. This inclined plane had a mechanical advantage of approximately 2.43.
Step Two: Inclined Plane 2
The second step is a second inclined plane. We calculated the rolling purple marble's acceleration down this plane to be approximately 4.52 m/s^2. We used railings in this step and the last to ensure that the ball stays on track and does not fly over the edge.
Step Three: Dominoes
Our third step was a chain of dominoes. This allows us to cover a large space in little time. Between each domino, one domino transfers its kinetic energy to the next. I calculated the acceleration of a domino to be 8.875 m/s^2.
Step Four: Hammer
The final three dominoes strike a hammer, which swings down 180 degrees. The hammer has a counterbalance weight of 20g to prevent it from constantly falling over. We calculated the hammer's potential energy (after the swing) to be 0.0882J. How come this is such a low number? The remaining potential energy is lost in heat, friction, sound and more.
Step Five: Wheel and Axle
When the hammer swings down, it converts its kinetic energy into rotational kinetic energy. This helps propel the wheel and axle down the groove in the board. A wheel and axle takes a force on either the wheel or axle and adds it to the other component. I calculated the wheel and axle's acceleration to be approximately 0.1372 m/s^2.
Step Six: Screw-Like Formation
The weights on the wheel and axle serve two purposes: Add more mass to the wheel and axle, and hit a marble down a screw. A screw allows our marble to both descend compactly and gain energy while doing so. We had a large error with the screw. If you view the video above, you will notice that it has very sharp angles. These angles often caused the ball to become stuck. We tried tampering with the angles, and even filing parts down, but to no avail. By finally adding a Popsicle stick at the bottom, the ball was able to hop up and perform it's next task: hit a weight.
Step Seven: Pulley System
The ball, which fell down the screw, hits a weight. The weight falls out of the end and tugs on a string. The string is attached to a pulley "system", which allows the next task to be completed. The reason I placed quotation marks around the word 'system', was because our pulley wasn't exactly a system. Typically, pulleys are used to decrease the force or work required to move an object. Our pulley just requires the same amount of work, it only reverses the direction of energy. For this, the mechanical advantage of our pulley is 1.
Step Eight: Class 1 Lever
There are three different classes of levers. Class one consists of a fulcrum (where the lever balances) between two ends, one with a load and another with effort (or force to balance the load). Class two consists of a fulcrum at one end, a load in the middle, and effort at the other end. The third class is a fulcrum at one end, the effort in the middle, and the load at the other end. Because our lever has the fulcrum in the center, it is a class one lever. The string used in the pulley system pulls one end of the lever up, causing the other to fall. The mechanical advantage of the lever is 1, meaning it is exactly the same force required to move one end as it is without the lever itself. Once again, this step reverses direction.
Step Nine: Wedge
A wedge is an acute angle used for splitting something, akin to a knife cutting bread. Our wedge is a blade, used to split to parts of a string. The force that the wedge exerts on the string is only 0.25N.
Step Ten: Car On Inclined Plane 3
A third inclined plane is used to let a car travel downward. The car is carrying a carrot to activate a surprise on my iPhone. The kinetic energy just before the carrot hits the phone is 0.074J.
Why Use A Carrot?
Touchscreens use bio-electricity, which allows organic substances to activate it. A stylus uses bio-electric silicon. As it turns out, vegetables you can buy at a supermarket (for cheaper) are more effective than a commercial stylus!
My project incorporates all of the simple machines and 10 steps, as shown in the video above. First, I will explain the steps.
Step One: Inclined Plane 1
The first step incorporates the simplest simple machine: the inclined plane. An inclined plane is a slope that allows masses to be raised or lowered a certain height with less work required. We used this simple machine to get the ball rolling, so to speak. Our first inclined plane had a vertical leg of 24.5 cm, a horizontal leg of 54 cm, and a hypotenuse of 59.5 cm. This inclined plane had a mechanical advantage of approximately 2.43.
Step Two: Inclined Plane 2
The second step is a second inclined plane. We calculated the rolling purple marble's acceleration down this plane to be approximately 4.52 m/s^2. We used railings in this step and the last to ensure that the ball stays on track and does not fly over the edge.
Step Three: Dominoes
Our third step was a chain of dominoes. This allows us to cover a large space in little time. Between each domino, one domino transfers its kinetic energy to the next. I calculated the acceleration of a domino to be 8.875 m/s^2.
Step Four: Hammer
The final three dominoes strike a hammer, which swings down 180 degrees. The hammer has a counterbalance weight of 20g to prevent it from constantly falling over. We calculated the hammer's potential energy (after the swing) to be 0.0882J. How come this is such a low number? The remaining potential energy is lost in heat, friction, sound and more.
Step Five: Wheel and Axle
When the hammer swings down, it converts its kinetic energy into rotational kinetic energy. This helps propel the wheel and axle down the groove in the board. A wheel and axle takes a force on either the wheel or axle and adds it to the other component. I calculated the wheel and axle's acceleration to be approximately 0.1372 m/s^2.
Step Six: Screw-Like Formation
The weights on the wheel and axle serve two purposes: Add more mass to the wheel and axle, and hit a marble down a screw. A screw allows our marble to both descend compactly and gain energy while doing so. We had a large error with the screw. If you view the video above, you will notice that it has very sharp angles. These angles often caused the ball to become stuck. We tried tampering with the angles, and even filing parts down, but to no avail. By finally adding a Popsicle stick at the bottom, the ball was able to hop up and perform it's next task: hit a weight.
Step Seven: Pulley System
The ball, which fell down the screw, hits a weight. The weight falls out of the end and tugs on a string. The string is attached to a pulley "system", which allows the next task to be completed. The reason I placed quotation marks around the word 'system', was because our pulley wasn't exactly a system. Typically, pulleys are used to decrease the force or work required to move an object. Our pulley just requires the same amount of work, it only reverses the direction of energy. For this, the mechanical advantage of our pulley is 1.
Step Eight: Class 1 Lever
There are three different classes of levers. Class one consists of a fulcrum (where the lever balances) between two ends, one with a load and another with effort (or force to balance the load). Class two consists of a fulcrum at one end, a load in the middle, and effort at the other end. The third class is a fulcrum at one end, the effort in the middle, and the load at the other end. Because our lever has the fulcrum in the center, it is a class one lever. The string used in the pulley system pulls one end of the lever up, causing the other to fall. The mechanical advantage of the lever is 1, meaning it is exactly the same force required to move one end as it is without the lever itself. Once again, this step reverses direction.
Step Nine: Wedge
A wedge is an acute angle used for splitting something, akin to a knife cutting bread. Our wedge is a blade, used to split to parts of a string. The force that the wedge exerts on the string is only 0.25N.
Step Ten: Car On Inclined Plane 3
A third inclined plane is used to let a car travel downward. The car is carrying a carrot to activate a surprise on my iPhone. The kinetic energy just before the carrot hits the phone is 0.074J.
Why Use A Carrot?
Touchscreens use bio-electricity, which allows organic substances to activate it. A stylus uses bio-electric silicon. As it turns out, vegetables you can buy at a supermarket (for cheaper) are more effective than a commercial stylus!