We began with a fairly classical Egg Drop.
Decisions had to be made due to a budget and the criteria and constraints were pretty simple. Drop the egg from 5 meters, no additional materials and no guts. Well, we got plenty of guts though a few successes. This launched our project which was tucked into the theme of drone delivery systems. (An eye opener for me as I learned more about the big idea was how much drone work is actually being done right now.) Students had to design a delivery system that would allow an object to be dropped from a drone from a height of up to 10 meters.
This project was nestled into a slot between winter break and a week-long Chinese New Year break. Hit it and quit it! As such, we settled into the idea of covering some basic concepts of force and motion and focusing heavily on the iterative process of design.
For this project, we really wanted students to zoom in on the process of developing a testing plan and using data to inform their decisions. A big challenge was that collecting force data on items inside a falling package did not seem to be a possibility. Oh the planning meetings that took place as we went round and round. If you have a great solution, please let me know! Ideally, we could measure the force of the collision on an object inside a falling box but this did not happen.
The next idea was to drop items onto a force plate and measure the force on the outside of the box. Then, we could use that value as a design target.
Using a Vernier force plate, we began dropping “unprotected” boxes. The data was horrible – completely unreliable and through some research we came to the conclusion that due to the super short impulse / contact time of the package and the force plate, coupled with different parts of the package making contact that the data was expected to be unreliable. Back to the drawing board…
Finally, we landed on the idea of using LoggerPro to measure the velocity of the package as it fell. If the velocity just before hitting the target was reduced, then the force on the contents would also be better.
That was happening “behind the scenes”. In the meantime, what were the students dropping and what all were they measuring. To get the students into the project, we decided to open it up for them to decide upon what would be delivered and what would be their metrics for success. Products ranged from coffee to clothing to first aid containers to fast food to electronics…The ideas were everywhere which made it a lot of fun. Groups then met to discuss what would be a successful design. Two metrics continued to repeat: a “soft landing” and accuracy. The landing was measured using the video analysis and the accuracy measured in distance from the force plate.
Goals were set for each group to make it through at least a couple of design iterations though after a slow start, many groups began iterating like crazy. It was as if a certain amount of tinkering time was needed before essential pieces were put together and then projects quickly moved forward. The final exhibition was scheduled for an audience of high school students and parents of our students. This exhibition would include a pitch where groups talked to “potential investors” about their designs and an 8 meter drop.
A few take aways on the project:
- Students were super into the act of iterating. In reflections at the end, it was voiced over and over how important this process is to a final design.
- Students wanted more time to work on their projects. Yep – it was a quick one!
- Students wanted access to more materials. At the beginning, I did not provide students with many materials. My hope was that students would search about a bit and have more creativity in their projects based upon gathered materials. This did not work out. More thought needs to be put into materials in the future.
- Groups can either excel or sink. It was a quick project and so apparent as to which students do not do their part.
- Dropping mechanisms that more simulate being released from a drone would be nice.
- Being up 8 meters on the machine can get a bit sketchy!