An important element to any PBL (Project Based Learning) is the kickoff. This is the time to capture the interest of students and enthusiasm for the upcoming project. What better way to launch a spring project on catapults and trebuchets than encouraging students at STEM High School in Chattanooga, Tennessee to take aim at a teacher, launching rubber balls from giant rubber tubing slingshots! The students, in groups of 4, had one chance to hit their target. They had a great time, not even realizing the collaboration and critical thinking that were taking place as groups strategized, made adjustments and encouraged other groups.
After a successful launch, the real work began for students, but to get to this point required a well coordinated effort from content area teachers, fab lab instructors and the guidance of Fab Foundation partners. The catapult unit supports the study of quadratic functions and Newton’s Laws as students research, design and build either trebuchets or catapults. Digital fabrication is incorporated using design software, a laser cutter and a 3D carving machine or “Carvy”. The benefit of digital fabrication is that it allows for multiple iterations in prototyping, and enables students to make adjustments to their launching device with better precision. Our ninth graders at STEM School Chattanooga had largely not had much experience using digital fabrication tools, so the challenge was to not only create an engaging academic unit but also to provide instruction in fab tools.
This is a project that could easily be completed in a math or science class, but at STEM School Chattanooga, we embrace cross curricular PBL’s and among the 9th grade teachers our attitude is to “go big or go home”! The benefit of including all core classes in the unit is encouraging students to build connections between the math and science as well as consider the historical purpose and construction of these devices.The culmination of the month long project was a celebratory series of challenges, where students tested their devices for accuracy and precision.
After the completion of the challenge, we brought together several student groups for a design review discussion. Each had varying success so it was interesting to hear their perspective of the project. We have never had small group debriefs at the end of our PBL’s, but we realized the power in allowing teams to present and and provide feedback to each other in a smaller , less intimidating setting than in a large whole group gathering.
As we celebrate the success of the unit, we have already begun reflecting in order to refine and improve the experience and student outcome. In order to capture the interest of our diverse student population, we have considered offering choice in the type of launching device. For instance, rather than just research and design a medieval trebuchet, students interested in sports could research and design a free throw or t shirt launcher. This was a lengthy project with many moving parts, so we created a pacing guide to help students stay on track throughout each iteration.. Next year, we would add a series of challenges at each stage to ensure that students really test their prototype for accuracy and precision, and adjust their design based on the results of the challenge.