Do you know what a film canister is? It’s a small plastic container that used to contain film. Do you know what film is? If you don’t, chances are you were born after 2003, which is about the time when digital photography overtook film photography. It’s interesting that the container that was used to store film has actually outlived the film itself; you can buy packs of film canisters on Amazon for about $0.50 a piece. They are useful for storage, art projects and film canister rockets.
At first, it may seem odd that Amazon recommends that you buy Alka-Seltzer along with a pack of empty film canisters, but if you head over to a website such as sciencebob’s (no relation) you’ll see that the “micro precision fitting lids” of film canisters make for fun rocket demonstrations. Add a quarter tablet of Alka-Seltzer along with a small amount of water, snap on the lid and watch the rocket shoot up several meters. (Try this outside, please.)
While it’s a fun demonstration of gas and pressure, I wanted to add a 21st century engineering component to it. So I put my research students to work on designing film-canister-like rockets that could be 3D printed and launched by a couple dozen 4th graders who happened to be visiting my lab. The rockets are designed to fit a #4 rubber stopper, which when clean, provided an adequate seal for pressure to build up within the rocket. Needless to say, the kids had a blast…
When writing the activity, I relied on the Next Generation Science Standards for engineering design.
- 3-5-ETS1-1. Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.
- 3-5-ETS1-2. Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.
- 3-5-ETS1-3. Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.
The problem was that my students had created a set of rockets and it was the 4th graders’ jobs to evaluate their performance (and improve upon them if possible). We identified the 1 meter mark as a specific criteria for a successful launch. They performed three (at least) replicate trials before discussing what changes could be made and what variables they could control. Finally they implemented one new change (how tight the stopper was fitted, amount of Alka-Seltzer, amount of water) and observed whether or not the changes made resulted in a positive change in the rocket performance.
What surprised me greatly was how well the children worked in groups (unlike my college students who passionately resist group work unless it is in the laboratory). I had the students work in groups of three, with each student playing a particular role: the data engineer was in charge of recording results; the fuel engineer decided the amounts of materials to use and the launch engineer stoppered the rocket and set it on the launchpad.
One group of girls was able to launch their rocket over 3.5 meters in the air, which is pretty close to what the traditional film canisters could do (and exceeded what I was able to achieve when piloting the lesson). During our reporting out stage, one of the girls responded, “now I am officially a scientist“. I consider that a great way to spend a Friday afternoon.
All photos are copyright 2019 Shauna Zurowski. I couldn’t have put this project together without the help of my colleague Kelly Roe and current and former students Dailianny, Sharlita, Calli and Megan.