What was our task?
A Rube Goldberg machine is a machine that uses multiple steps and simple machines to complete a simple task in a complicated manner. We built a Rube Goldberg machine with a Christmas theme. There were two end goals, to lower a star onto a Christmas tree and to light up Christmas lights around the tree and the board. Some other Christmas themed items that were incorporated were a Christmas train, and Christmas ornaments. We had nine days to build this machine, as well as a few days for preparation and a few to decorate the board and create a presentation. It had to include at least four energy transfers, ten steps, and five different simple machines.
A Video of Our Machine
What Are Simple Machines?
Simple Machines- Any of the basic mechanical devices for applying a force.
Lever: Consists of a rigid bar resting on a pivot, or a fulcrum. When pressure is applied to one end of the bar, it helps move a load on another. We had a marble hit a lever, pushing the other side up and dislodging a second marble.
Pulley: A wheel with a grooved rim through which a cord passes. It can be used to lift weights. We had a pulley that lowered the star onto the Christmas tree when a marble fell into it.
Wedge: A piece of wood or metal that has a slanted edge. We had a wedge holding a marble in place.
Inclined Plane: A ramp that allows something to go up or down. We had a few inclined planes in our project that had marbles roll down them.
Wheel and Axle: A wheel with a rod through the center that rotate together. Our train had multiple wheels and axles.
Screw: An inclined plane wrapped around a cylinder.
Evidence of Work
Our machine had ten steps, which are listed below.
1) The train is turned on and chugs across the rails at 0.572 m/s.
2) The train pushes a 96.2g domino with 1.029 J of PE past its center of gravity, causing the domino to topple.
3) The domino takes 0.39s to hit a 19.2g marble at rest with 0.2055 J of PE, causing it to fall 0.2032m with a velocity of 0.58 m/s and 0.0032 J of KE.
4) The marble rolls down two ramps, one with an ideal MA of 1.84 and another with an ideal MA of 8.24, then loses velocity due to friction between two pieces of wood.
5) The marble falls on a tilted lever with an ideal MA of 2.923 and falls in the opposite direction.
6) The lever unhinges a 17g marble with 0.01 J of PE.
7) The 19.2g marble rolls down two ramps, one with an ideal MA of 4.416 and another with an ideal MA of 7.122 and collides with a 19.3g marble wedged at rest with 0.9511 J of PE.
8) The 19.3g marble falls 0.13335m at a velocity of 0.66675 m/s and a KE of 0.00428 J and collides with a 9.8g wood block that turns on the lights.
9) The 17g marble falls into a pulley with an efficiency of 46.81%.
10) The pulley lowers a star onto the Christmas tree.
1) The train is turned on and chugs across the rails at 0.572 m/s.
2) The train pushes a 96.2g domino with 1.029 J of PE past its center of gravity, causing the domino to topple.
3) The domino takes 0.39s to hit a 19.2g marble at rest with 0.2055 J of PE, causing it to fall 0.2032m with a velocity of 0.58 m/s and 0.0032 J of KE.
4) The marble rolls down two ramps, one with an ideal MA of 1.84 and another with an ideal MA of 8.24, then loses velocity due to friction between two pieces of wood.
5) The marble falls on a tilted lever with an ideal MA of 2.923 and falls in the opposite direction.
6) The lever unhinges a 17g marble with 0.01 J of PE.
7) The 19.2g marble rolls down two ramps, one with an ideal MA of 4.416 and another with an ideal MA of 7.122 and collides with a 19.3g marble wedged at rest with 0.9511 J of PE.
8) The 19.3g marble falls 0.13335m at a velocity of 0.66675 m/s and a KE of 0.00428 J and collides with a 9.8g wood block that turns on the lights.
9) The 17g marble falls into a pulley with an efficiency of 46.81%.
10) The pulley lowers a star onto the Christmas tree.
Construction Log
Day 1- We picked out our piece of wood, after deciding that we wanted an entirely vertical board. We started by sketching our blueprint onto the board, so it would be easy to see what step we needed to do next.
Day 2- We stabilized the board by drilling wood blocks onto the bottom of the board. There are two on either side of the front and one in the middle of the back. The board can now stand up on its own. We also spent some time experimenting with different steps, to find out what would work and what wouldn’t.
Day 3- Today we drilled in the wood planks that the train will be on. Our first three steps our on that board.
Day 4- We started working on the screw today, by running multiple test trials. After attempting to hot glue the screw, we concluded that it wasn’t going to work, and came up with an alternate solution. Zach started working on a different design of screw.
Day 5- Today we drilled in another ramp. We wanted to make it half slanted and half horizontal, so we cut the board in half with the miter saw. We also started brainstorming ideas for the lever.
Day 6- We actually built the lever today, and also started designing the Christmas tree on a plank of wood. At the end of class we drilled in a piece of wood that the marble that activates the pulley could roll on.
Day 7- We cut the Christmas tree out and also started designing the star. We drilled in the ramp the leads to the button that activates the lights. It took a few test tries to be able to decide where we should secure pieces of wood that control where the marble falls. We came across a problem with the train. After it hit the dominoes, it would keep going. We needed to be able to stop or reverse it, so we glued in a ruler that hits the button and pushes it backwards.
Day 8- The screw didnt work so we had to drill in a ramp instead and start brainstorming ideas for another simple macine to incorporate in place of the screw. We also started working on the pulley and postioning the dominoes correctly. We had some trouble with that because they had to be hit in the exact right spot in order to fall correctly. The train hit the dominoe at the bottom, so it would fall backwards instead of forwards. To fix this, we glued a piece of wood on the top of the train the hits it at the top.
Day 9- We put colored paper on the star and Christmas tree. We also finished the pulley and made sure that the weight was balanced on both sides. The star had to be attached to the bottom of the pulley. We positioned and secured the train tracks correctly and used a wedge by positioning the marbles differently at the bottom. One marble is wedged using in place using a picee of wood, and another one knocks it. We added and took out a few dominoes in order to make the machine more reliable.
Day 1- We picked out our piece of wood, after deciding that we wanted an entirely vertical board. We started by sketching our blueprint onto the board, so it would be easy to see what step we needed to do next.
Day 2- We stabilized the board by drilling wood blocks onto the bottom of the board. There are two on either side of the front and one in the middle of the back. The board can now stand up on its own. We also spent some time experimenting with different steps, to find out what would work and what wouldn’t.
Day 3- Today we drilled in the wood planks that the train will be on. Our first three steps our on that board.
Day 4- We started working on the screw today, by running multiple test trials. After attempting to hot glue the screw, we concluded that it wasn’t going to work, and came up with an alternate solution. Zach started working on a different design of screw.
Day 5- Today we drilled in another ramp. We wanted to make it half slanted and half horizontal, so we cut the board in half with the miter saw. We also started brainstorming ideas for the lever.
Day 6- We actually built the lever today, and also started designing the Christmas tree on a plank of wood. At the end of class we drilled in a piece of wood that the marble that activates the pulley could roll on.
Day 7- We cut the Christmas tree out and also started designing the star. We drilled in the ramp the leads to the button that activates the lights. It took a few test tries to be able to decide where we should secure pieces of wood that control where the marble falls. We came across a problem with the train. After it hit the dominoes, it would keep going. We needed to be able to stop or reverse it, so we glued in a ruler that hits the button and pushes it backwards.
Day 8- The screw didnt work so we had to drill in a ramp instead and start brainstorming ideas for another simple macine to incorporate in place of the screw. We also started working on the pulley and postioning the dominoes correctly. We had some trouble with that because they had to be hit in the exact right spot in order to fall correctly. The train hit the dominoe at the bottom, so it would fall backwards instead of forwards. To fix this, we glued a piece of wood on the top of the train the hits it at the top.
Day 9- We put colored paper on the star and Christmas tree. We also finished the pulley and made sure that the weight was balanced on both sides. The star had to be attached to the bottom of the pulley. We positioned and secured the train tracks correctly and used a wedge by positioning the marbles differently at the bottom. One marble is wedged using in place using a picee of wood, and another one knocks it. We added and took out a few dominoes in order to make the machine more reliable.
The Physics Principles and Equations That We Used
Velocity- Rate of covered distance in a direction. You can find velocity by dividing the distance by the time. The units for velocity are m/s^2. The train had a velocity when it was in motion.
Ideal mechanical advantage- How much farther you have to push due to using a tool. Higher mechanical advantage means that you can due more work, put over a longer distance. You can find the mechanical advantage by dividing the effort by the load. The pulley had a mechanical advantage.
Kinetic energy- Energy due to motion. Found by multiplying mass times velocity squared, and dividing by 2. The unit for kinetic energy is joules. The marble has kinetic energy when it is rolling.
Potential energy- energy an object has due to its position at a height or in a gravitational field. An object has more potential energy if it's higher up. You can find potential energy by multiplying mass, acceleration due to gravity, and height. The unit is joules. The marble had potential energy when it was sitting still.
Acceleration- Rate of change of velocity (speeding up or slowing down). Acceleration is found by dividing the change in velocity by the change in time. Unit is m/s^2. The marble had acceleration when it was moving.
Mass- Amount of matter in an object. Mass is not affected by gravity, and the units are kilograms. The marbles that we used all had different masses.
Force- The push or pull on an object. Force is found by multiplying mass and acceleration, and is labeled with newtons. The train exerts force on the domino when it hits it.
Work- Amount of energy put into something. Work can be found by multiplying force and distance. The units are in joules.
Acceleration due to gravity- gravity is a force between objects in proportion to their masses and inverse to the distance between them. Acceleration due to gravity is always 9.8 m/s^2.
Momentum- tendency of a moving object to keep moving, or how hard it would be to stop it. The marble had velocity when it was rolling down the ramp.
Ideal mechanical advantage- How much farther you have to push due to using a tool. Higher mechanical advantage means that you can due more work, put over a longer distance. You can find the mechanical advantage by dividing the effort by the load. The pulley had a mechanical advantage.
Kinetic energy- Energy due to motion. Found by multiplying mass times velocity squared, and dividing by 2. The unit for kinetic energy is joules. The marble has kinetic energy when it is rolling.
Potential energy- energy an object has due to its position at a height or in a gravitational field. An object has more potential energy if it's higher up. You can find potential energy by multiplying mass, acceleration due to gravity, and height. The unit is joules. The marble had potential energy when it was sitting still.
Acceleration- Rate of change of velocity (speeding up or slowing down). Acceleration is found by dividing the change in velocity by the change in time. Unit is m/s^2. The marble had acceleration when it was moving.
Mass- Amount of matter in an object. Mass is not affected by gravity, and the units are kilograms. The marbles that we used all had different masses.
Force- The push or pull on an object. Force is found by multiplying mass and acceleration, and is labeled with newtons. The train exerts force on the domino when it hits it.
Work- Amount of energy put into something. Work can be found by multiplying force and distance. The units are in joules.
Acceleration due to gravity- gravity is a force between objects in proportion to their masses and inverse to the distance between them. Acceleration due to gravity is always 9.8 m/s^2.
Momentum- tendency of a moving object to keep moving, or how hard it would be to stop it. The marble had velocity when it was rolling down the ramp.
Reflection
There were many difficult parts of this project, and not all of them were about physics. One thing I struggled with a lot was getting frustrated. I would get easily frustrated with my teammates when they were distracted or not doing their work. I had to learn to calm down and be more understanding. I would also get frustrated with our project when it didn’t work and we couldn’t find a way to fix it. I had to learn how to find alternate solutions. Another thing I had to control was my urge to do all the work myself. I found it incredibly stressful trusting other people to do all the work, so I tended to be a bit controlling. I had to learn how divide up work evenly, and trust my teammates. I think I improved a lot in my team communication skills, and learned a lot about group work. One thing I was good at was completing tasks on time and working hard to get things done. I came in at lunch to finish and decorate the machine, and was always on task in class.