Disclaimer: No Red-eyed tree frogs named Otis were harmed in the making of this marble run.
I think the power of this concept is in the timing. If you print a few pieces in advance you can spend a day or two exploring on a bulletin board or blackboard. Spend a week and change the objective each day (timing, speed, accuracy, collaboration...). Or just 'run' with it and spend two months and counting designing custom pieces and perfecting the design.
A long term, multidisciplinary collaborative project. Students experience the engineering design process from start to finish. The OVERWHELMING enthusiasm from the students has been the single driving force behind the development of this project and, indeed, the creation of it. There might just be an uprising (thumbtacks and marbles O my!) if I dare interrupt this project with a quiz or test. The students have been more focused than I could have hoped.
The goal of the project, simply stated, is to create a marble run that mounts entirely on a large bulletin board. The bulletin board is divided into equal sections and each student is randomly assigned to one section(after much collective practice). Students are required to create their own custom pieces that demonstrate the mechanical advantage of one of the six classical simple machines.
In addition to the physical marble run students conduct experiments and create presentations about simple machines as the project progresses. They record audio presentations that discuss the design process and, of course, teach visitors about simple machines. The audio presentations are triggered by various buttons controlled by a raspberry pi. The audio box and other electronic components are being designed and built by my high school engineering class.
In addition to the included pdf here is a link to the document that will update in real time as we continue to develop the project:
You can drag the center bar so you don't have to look at the code. If you download the PDF from the link the hyperlinks/references are clickable and will take you directly to the site.
The project is in its final phase. Students are perfecting their custom pieces and the board is sectioned off so each student is responsible for their own section. Students must communicate with their neighbors in order for the entire marble run to work seamlessly.
Straight Track Section
The STL included is a modular straight track section. This piece was designed in OpenSCAD using a linear extrude of a 2D outline. Track length and size of the peg hole are easily manipulated. The default is 130mm length and 7mm diameter holes to fit the VMR 6mm standard pegs. 6mm was chosen because it fits the K'nex sets we have used in class.
The set of 12 takes about 9 hours to print at default speed on our flashforge creator pro.
The folder with all the design files and pieces for this project has reached over 600 mb and according to our printer we have used over a mile of filament.
Some notes about the variables:
track_length, peg_radius and track_width are easily adjustable. Some of the other variables need to be clarified. track_radius has to do with the curvature of the track itself in creating the 2D outline for extrusion. track_height also concerns the 2D outline. You can play with the variables but proportions are not built into the script.
Other pieces (all customizable) include 90 degree bend, 180 degree bend (good for reversing direction), inverted 90, inverted 180 and others types of pegs will be posted separately. The idea: Combined together you can create all kinds of curves and bends. The system is not perfect yet. The pieces will be made to interlock so that no shifting is possible. The pegs also need to be tweaked and threaded so a cap can be screwed on to hold gears and such in place.
I think every teacher would agree that the most rewarding affirmation of their hard work is the resonating sound of disappointment when the bell rings ('gong' in our case). Since we started this project (initial phases started way back in December) there have been many occasions where I have had to 'shoo' the kids out of the room so they are not late for their next class.
This project is being done by the fifth grade but my twelfth grade engineering students will tell you it's fun (and challenging) for all ages. The engineering class has been following this project closely and has helped shape the rapid design of the system with their valuable feedback. Their encouragement and support should be recognized.
Students should have some previous 3D modeling experience. Students in this class did the 'chess piece challenge' earlier in the year.
Phet simulations were used to introduce students to conservation of energy and balancing torques. Various mini challenges and assignments have been inserted in between phases to allow time for printing.
Printing time is immense. To get started quickly look up 'VMR rapid deployment' system to use cheap PVC pipes.
- Patience, patience, and more patience
- Large bulletin board or magnetic surface
- 3D printer (we have a flashforge)
- Incredibly motivated students and supportive faculty who will tolerate marbles and thumbtacks popping up all over the building
- Thumbtacks or pushpins (lots!)
- Marbles (lots!)
- Multiple storage containers (trust me)
- Take care of Otis
- Check on the plants
- Rinse (aka discuss)
For a detailed write up please see the attached pdf or follow the link in the summary.
I will let the students speak for themselves:
*I have made no edits to these responses and the survey was optional. Thank you those who responded.
How has having access to a 3D printer in school impacted your educational experience?
- "Having a 3D printer in school has made learning science more engaging. Instead of just doing worksheets all of the period, we get to use the 3D printer and print objects that we have created on either OpenSCAD or Tinkercad and incorporate them in whatever we are learning or projects."
- "It is helping us learn more about geometry and the challenges of making things we take for granted."
- "Yes, in many ways because it gave science class a whole new concept."
Do you think hands-on projects are more effective than pad & paper learning when it comes to studying physical science?
- "Yes, they are by far more important because we learn as we do something and that is superior. We see the results as we make them. We may fail and that is also part of learning. We may be frustrated in the beginning, but the more hand-on projects we are involved in, the better our chances to improve our learning skills and be ready for the ready for the challenges in the world."
- "Definitely more fun and effective."
- "Yes. I believe that when students do hands-on work, they have a greater interest in the project. The students are more likely to have a good time and learn new things when doing projects like this. I think 3D modeling is a great way to start. It can also help students to become curios about new technologies and perhaps future careers."
What is your opinion on the marble run project? What have you learned so far?
- "The marble run is extremely fun to build. I am glad we're doing it. I am learning about speed and a little bit of accuracy."
- "When I learned that my class would make a marble run, I was overjoyed. I love marble runs and wanted to get right to work. I have learned much more about 3D modeling and I am continuing to do so."
- "I learned how to use the 3D printer better. The project is fun but I would like to do more coding on the buttons. It's a fun way to learn about simple machines."