Why am I writing this personal entry? Well, it is not an attempt to gain any sympathy. It attempts to show what is possible if a clear intention and goal serve the learner's needs. In May of 2022 just near the end of another fantastic school year, I do not remember what happened. But, I was unable to finish the school year and was unable to teach the following year. Why? On May 21st, 2022, I fell down a flight of 16 stairs (luckily carpeted) from the 2nd to 1st story of our home. I was found at the bottom of the stairs. I was found foaming at the mouth. This would lead to a 2-month hospital stay which included an induced coma because my seizures would not stop, several rounds of lumbar punctures, and relearning basic physical movements like something as simple as being able to roll in the hospital bed. Simply put, when I was admitted to the hospital, I was diagnosed as being “critically ill.” Please take a moment and read those words: critically ill. They are not terms...
Last year we took a big risk in our physics classroom and decided to take on a huge project in which students fabricated chariots for Spheros. The project incorporates science and engineering standards as a part of the process and the project required students to have a chariot which had a piece that was fabricated using a 3D printer and one piece that was laser cut. Last year students collaborated on their designs with a Project Lead the Way engineering class so they weren’t required to build the 3D digital models that would be printed. This year, we didn’t partner with an engineering class and groups had to do all the work on their own from design through fabrication.
Now that this 10 day project is finished, I am able to look back on the successes and challenges of the project in hopes of building on it when I have a new group of physics students in 3 months.
Here’s the overall scheduling of the project. On days 4-6, groups rotated through the print and cut process. Those not printing or cutting were working with momentum content pieces via lecture, practice problems, and labs.
The project was originally scheduled for fewer days but the major factor for it being longer than planned was the bottleneck of 3D printing that will be discussed below.
Step 1: Introduction and Initial Design Work
The goal of the project for the students is for them to design and build a chariot that will carry a 50 g passenger safely around a course in the shortest amount of time. The constraints are that they need to have at least one 3D printed piece and at least 1 laser cut piece.This forces them to think of designing in 3D for the printing and 2D for the laser cutting. The first day we introduced the project and had some designs from last year that students could drive around and get ideas from. They then reflected on what they’d like to include in their design and what they should not include in their design. Finally, they sketched out their designs with measurements.
While it was great to have past year’s designs for students to test out, the 3D models were built by engineering students who were very familiar with the software and could make complex ideas a reality. Our students had no previous experience designing 3D models. So the may have seen a design that they liked, but may not have had the ability to reproduce it without a huge amount of time dedicated to the process.
In addition, I quickly learned that sketching out models was not the best way to communicate a true representation of what they hoped to make as it didn’t communicate all of the dimensions that they would need to know.
What to consider for next time
First would be the communication of the goal. To be honest, many of our groups failed to have a true “rider” in their chariot. Rather than having it be about the mass of the rider, I’d just like it to be about the rider itself and have a little fun with it. Some students brought in Lego figures some stuffed animals. But groups who forgot about needed a rider, just taped some pennies together. I feel that took a little away, but that’s a small nit pick.
The bigger concern is having students think in 3D about their design and the required measurements. I feel that while it is a good idea for them to have a sense of the dimensions, they don’t make as much sense until students are designing in 3D. I’m not sure if there is a way for students to do this physically before we jump to the digital tools.
Step 2: Digital Models
Students needed to build their models to be 3D printed and laser cut on their Chromebooks. So, we used TinkerCad. TinkerCad is a piece of software I knew very little about. To be honest, I know very little about the 3D printing and laser cutting process. TinkerCad has some nice tutorials to deal with the navigation. One of the biggest issues we had with TinkerCad were the dimensions. Students had major issues translating dimensions in the real world to the digital world. Building a check system into the process before students move to actually print their pieces.What to consider for next timeHaving students move to TinkerCad as soon as possible I think would help with the design process. Including check points for designing the look and the dimensions of their pieces would be essential before allowing them to move on to the printing stage. Having a detailed series of checks in which teacher and groups could check their designs to be sure it is what they wanted is key.
Step 3: Printing & Cutting
In TinkerCad, files can be exported at .stl if 3D printing or .svg if laser cutting. While I know how to get that far on my own, the next steps are still a mystery. Our Fabrication Lab Coordinator Tina Berna needed to handle all of these duties of helping students import .stl files into Astroprint in order to slice them and print them. We have a 2 large bed printers and a handful of smaller bed printers. What ended up happening was a lot of waiting for prints to be done because so many jobs were in the queue for the larger printers. Mind you, we had 30 different groups trying to print on about 7 machines. And, some of those groups were just waiting for the larger printers to be done. Because those are larger jobs, they take longer. So finding some way to stagger the project or pad the post print time is key. The laser cutting is fast. It’s the printing that creates a bottleneck.
What to consider for next time
First off, I need to learn more about the process. That way, I can get students to the stage where all they need to do is put their printable file in the queue. To help ease the print time issue, I could do a couple of things. One is staggering classes so we aren’t all trying to print at the same time. Another could be just building more content instruction into the time between printing and assembling.
Another possibility is limiting all groups to a single piece to be 3D printed that has size constraints. That would ensure that all prints could be done on any machine and that the jobs would be shorter in time. So when students go to create their 3D print model in TinkerCad, there is a set size for the workspace that they can’t design bigger than.
So while assembly was easy for some groups, those that made errors in design had to use some of the supplies we had in class to help re-engineer their original design. While some were able to roll with this without too much stress, some needed much more help from us in ideating.
First off, I need to learn more about the process. That way, I can get students to the stage where all they need to do is put their printable file in the queue. To help ease the print time issue, I could do a couple of things. One is staggering classes so we aren’t all trying to print at the same time. Another could be just building more content instruction into the time between printing and assembling.
Another possibility is limiting all groups to a single piece to be 3D printed that has size constraints. That would ensure that all prints could be done on any machine and that the jobs would be shorter in time. So when students go to create their 3D print model in TinkerCad, there is a set size for the workspace that they can’t design bigger than.
Step 4: Assembly
After all the parts were printed and cut, we began assembly. Some groups did fine with this part. Their pieces turned out exactly as they had planned and worked to a tee. It was just a matter of some hot gluing pieces together and drilling a few holes. Other groups ran into lots of problems here. The main reason was in their 3D models. In most cases, they failed to accurately size their holder for the Sphero and it was too small. Again, this is a step that could be addressed in the design stage in terms of a quality control check with the teacher before being allowed to move on to the printing phase. While we were easily able to prototype the laser cutting with a piece of cardboard, there wasn’t time to print low quality models before going to a higher quality print. Maybe even using Play-dough for initial dimensions could work. I would love ideas for this.So while assembly was easy for some groups, those that made errors in design had to use some of the supplies we had in class to help re-engineer their original design. While some were able to roll with this without too much stress, some needed much more help from us in ideating.
What to consider for next time
I’ll go back and reiterate the need for quality checks before printing, but I think there are a couple of other things I can do. While we 3D print and laser cut the pieces in the Fabrication Lab, the pieces are all put together in our physics space. Hot glue guns were limited so groups did have to share them. But, a big supply that I need to order are scissors! Over the years my 20 scissors have gone walking and I now only have 2. So, I’ll be sure to stock up on those. But, having supplies like popsicle sticks went a long way to help in body construction. The best supplies were actually straws and wooden skewers to build the axles. One of the teachable moments for many groups was that the axle and wheels need to be attached so when the axle rotates. Also the axle should be free to rotate and not glued to the body. Straws glued to the body worked great for allowing an axle to freely rotate.
Step 5: Programming
In order to program the Sphero chariots, students use the SpheroEDU app on iPads. It’s basic block programming so it is easy to learn and tweak for students. Last year, we ran chariot races in the hallway.
This year to reduce disruptions, we ran them in our classroom. The one downside to this was that the width of the course was decreased. This reduced the allowances between slight errors in aiming and some random acts of variation due to slight differences in how the Sphero runs or the chariot design.
The biggest issue we run into during this phase is ensuring everyone has an equal opportunity to program on our one course. There may not be a fix to this considering our space limitations, but I think I just need to design a more organized testing queue. Regardless, it was lots of fun watching as students troubleshooted designs and programs in this stage of the process. As they were able to watch other chariots perform, they quickly realized what worked and what didn’t.
But grading…
Ultimately the goal of the project is to design and race a chariot. Students then use their chariot to collect, analyze, and present data on velocity, acceleration, force, and momentum. So while the chariot itself is not a major grade, it is the vehicle through which students can be assessed on content standards. So even if the chariot doesn’t finish the course, it doesn’t affect the students grade. So there is no chariot rubric. There is a data collection sheet that I am tweaking and will continue to tweak. But one option students have at the end of the unit is to use the chariot as a way to collect and present data towards our unit assessment. Here is a link to the slideshow. The instructions for what students need to do on each slide is found in the speaker notes.
So moving forward, I hope to implement some changes in each step of the process.
Step 1: Intro & Initial Design
Race Day
On race day, we used Flippity to create a randomized bracket and race chariots 2 at a time.
But grading…
Ultimately the goal of the project is to design and race a chariot. Students then use their chariot to collect, analyze, and present data on velocity, acceleration, force, and momentum. So while the chariot itself is not a major grade, it is the vehicle through which students can be assessed on content standards. So even if the chariot doesn’t finish the course, it doesn’t affect the students grade. So there is no chariot rubric. There is a data collection sheet that I am tweaking and will continue to tweak. But one option students have at the end of the unit is to use the chariot as a way to collect and present data towards our unit assessment. Here is a link to the slideshow. The instructions for what students need to do on each slide is found in the speaker notes.
So moving forward, I hope to implement some changes in each step of the process.
Step 1: Intro & Initial Design
- Provide more constraints based on number of total groups (only 1 3D printed piece)
- Have group members ID themselves as part of 3D print team or laser cut team
- Have students bring in their chariot rider on second day
- Begin working in TinkerCad as part of first design to draw rough shape of chariot
- Require each member of team to design something in TinkerCad
- Set size constraints for 3D printed pieces
- Teacher quality control required before advancing to print phase with any design
- Possible Play-dough prototype before printing
- I need to learn how to do this stuff
- Schedule content related activities that can be completed while students are waiting for pieces to be printed or chance to laser cut.
- Get more glue guns and scissors in the classroom.
- Design a system for students to practice. (A structured lineup or perhaps 3-5 minute testing windows)
This project is constantly in revision and I would love to hear your thoughts, ideas, and questions.
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