DESCRIPTION: For our first STEM project of year, we were assigned to build a Rube Goldburg project, a complex machine that in the end does a very simple task. Rube Goldburg was a cartoonist who would draw cartoons about outrageous gargets that would perform various tasks, such as sharpening a pencil or pulling an olive out of a bottle. In my group, (Mackenzie Elmhirst, Michelle Frid, Quinton Graybeal), we decited to stamp an "A+" on a piece of paper. For this project, we needed to have at least five out of six simple machines, four energy transfers, calculations using Potential energy, Kinetic energy, work, Mecanical advantage, Force, and Velocity, a building log, a schematic (aka blueprint) and at least ten steps. Below is a video of our project working for the first time after many days of building:
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Physics concepts: Force- a push or pull, and it can be calculated by multiplying mass times acceleration. For example, the weight exerts a force on the marble when it goes down the zipline in our first step. Velocity- The rate of distance covered in a direction, calculated by dividing distance by time. When the marble rolls down the inclined planes, it has a certain velocity. Mechanical Advantage- How much easier it can make the machine work. It is calculated by dividing the input distance by the output distance. Our pulley had a mechanical advantage of 1, so it had no advantage. Work- The amount of energy applied to something. It is calculated by multiplying force and distance. When the marble goes down the last ramp, and it hits the car, it has done some work. Potential energy- the energy an object has due to its position, and it can be calculated by multiplying the mass, the acceleration due to gravity, and the height of the object. The weight coming down the zipline has potential energy, right before it hits the marble. Kenitic energy- kenitic energy is the energy an object has due to motion. It is calculated by multiplying 1/2 of the mass and the velocity squared. The potential energy of the weight is transferd to the marble, which then becomes kenitic energy. Acceleration- the rate of change of an objects motion, which is calculated by dividing the change in velocity and the change in time. When the marble goes down the screw, the acceleration rate slows down.
Daily log;
Day 1: Attached 2 ft x 4 ft pieces of wood together for the base of the machine Day 2: built the zipline and the first ramp. Day 3: built the second and third ramp, as well as pulley. Day 4, 5, & 6: built the lever, and worked on the screw. This took us a while, since we kept finding problems with the screw. Day 7: used a wooden pole to support the screw, which worked the best for our group. Day 8 & 9: built the final two ramps, and the wooden stand. Then we just kept perfecting the final product.
Simple Machines: Pulley Lever Screw-tube Inclined planes-rams wedge-knife
energy transfers
1.Kinetic energy is transferred from the weight on the zipline to the marble on impact. 2.Marble falls into the cup transferring kinetic energy to potential energy.
3.The pulley transfers energy to the lever.
4.The marble the lever transfers kinetic energy to the car as it hits the car. Calculations
Potential Energy of the Zipline
PEg=0.2kg(9.8 m/s²)(0.1m)
PEg=0.196 J
Kinetic Energy Transferred to the Marble
KE=PE
KE=0.196 J
Work of Marble moving down Fourth Ramp
W=0.052m/s(0.33m)
W=.017 J
Mechanical Advantage of Pulley
1 pulley
MA=1
Force of Marble Moving through Screw
F=0.2m(2.29m/s)
F=0.46 N
Velocity of Marble Down Last Ramp
V=1.12192s/2.8
V=0.44 m/s
Steps Step 1: Pulley and mass go down the zipline, and the mass hits the marble off of the platform. The marble jumps off to the next ramp.
Steps 2,3,4: The marble rolls down the ramp switching from the first ramp to the second and third ramps.
Step 5: The marble rolls down ramp and it falls into one of two cups that are attached to a pulley. The weight of the cup then sends the other cup on the other side of the pulley up, hitting the lever. Step 6: cup hits lever, which releases another marble down the next ramp.
Step 7: marble goes down the ramp,and then goes on another ramp which goes into the tube.
Step 8: marble goes through the tube, and goes on the next ramp.
Step 9 and 10: marble goes on a ramp, then lands on another ramp which rolls to hit a car, which then hits the knife.
step 11: knife falls down and cuts string, that was suspending a weight in air.
Step 12: weight that was suspended in air falls down.
Step 13: weight lands on stamp, which then stamps an A on the piece of paper.
Reflection: I thought that our group in the end worked well, but we could have done much better. We were not very efficient, and we did not know how to work together well as a group. I think that my other groupmates thought that only one person should work on one step at a time, which meant that I ended up finding pieces of wood or other supplies instead of actually working. This really slowed us down, and I think that I was really underestimated in my group in terms of what I could offer. We were constantly finding different problems with our machine everyday, and one of our most major problems with the machine was the screw. For the screw, We thought that we could drill four holes into the wooden wall and then twist the tube into the holes, but the marble would not go through, because the tube was too tight. Then, one of our group members decited to cut the tube in half without letting the rest of the members know, and then we had to duct tape it back together, because his idea didn't end up working. We then thought that the screw could be duct taped to a stand, but the stand was not strudy enough. We then decided to have a wooden pole holding the screw, which worked the best. I feel that towards the end is when we really started working together more. Overall, I think that I learned about leadership and time management in this project. I felt that I should have tried harder to express my ideas and to make sure that I was constantly contributing to the group, instead of just following whatever someone else tells me to do. Also, I think that next time, everyone should be working on the machine at the same time, instead of waiting for one step to be finished. This would have saved us a lot of time, and then we would have had less problems with every step. This was a very good first project, and I hope to improve in the next project.