Seton Hall Prep (SHP) launched its inaugural Introduction to Engineering Honors course in the summer of 2015 with eight motivated SHP students. Their first opportunity for design was that of a projectile and launcher. The Edison Innovation Foundation was there to support the testing phase. Teachers out there reading this … what a great student activity!

Project teams of two or three students completed the design using Tinkercad (free online software) and printed the projectiles and launchers in biodegradable PLA (polylactide) plastic with SHP’s 3-d printer, a 5th Generation Makerbot Replicator. Each team was given a small bungee cord for propulsion, which needed to be factored into the launcher design. The projectiles were launched horizontally from a height of one meter using only one finger to fire the device, necessitating a trigger mechanism for each design. Students used their mastery of kinematics (the geometry of motion) to model the flights of the projectiles.

Teacher Kelly Searfoss prepares to launch a test projectile as a student holds the launching apparatus steady (check out the math on the whiteboards … no math-o-phobia here!)

The goal for each team was to maximize both the accuracy (how close projectiles landed to the target) and precision (how close multiple launches landed to one another) of ten launches aimed at a target on the ground five meters away. Each of the landing sites was marked on the floor as the testing proceeded, and then their x- and y- distances (perpendicular to and parallel to the launch direction) from the target were measured.

Students gather around to take stock of their hand-held videos of each launch to enthusiastically record just where the projectiles landed. Competition is fun!

The relative accuracy of each group’s design was evaluated in each direction by calculating the average distance from the target. Students calculated the standard deviation of the measurements in each direction to provide a measure of the relative precision of each design. As expected, the groups generally found that their launches displayed better accuracy and precision in the x-direction, as it was more difficult to ensure that the projectiles traveled 5 meters each time than to keep the launches straight.

Students concluded the design project with a formal report outlining the physical concepts of projectile motion and kinetic and elastic potential energy, their mathematical evaluation of their design strength, and their experience with the trial-and-error nature of the design process.

Some student quotes about this engineering design experience-

“We came out of this activity realizing the importance of communication in engineering.”

“We learned first-hand what teamwork feels like; and will use this skill as we move on to college and professional careers.”

“The way Edison invented a whole new way to invent made us realize how great an innovator he was, serving as a role model for all of us in our engineering careers.”

Contact Kelly Searfoss directly at SHP if you want more details.

Go Pirates!

Thomas Edison said, “I find out what the world needs. Then I go ahead and try to invent it.”

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