Bridge Builders

Challenging middle and high school students to building bridges out of toothpicks or Popsicle sticks is a time honored activity in science classrooms the world over, but this is the 21st century! With 3-D printing we can now take that same lesson to another level of understanding, infusing it with design, by replacing wood and white glue with PLA filament.
How I Designed This
I created all things on Tinkercad, but any modeling program should suffice.


Standards



NGSS


Overview and Background
Bridge building seems tailor made for a 3-D printing project. Beginning with research on bridge types (see link below in Reference section), transitioning to the design process, considering dimensions and amount of material used, and concluding with display and presentation, every step along the way will build an authentic and meaningful learning opportunity for your students.
Objective:
Students will explore the principles of bridge design while expanding their experience with 3-D modeling and desktop fabrication. Lesson Plan and Activity
Audiences
This lesson is intended for middle and high school students in physics, engineering, design, or general science classes. This lesson can be modified for younger students if given appropriate support with the design process.
Lesson/Activity:
Assign partners or teams the task of designing and printing three different types of bridges. I recommend that conducting research on the bridge styles available be part of the assignment.
Give an introduction to Tinkercad (if students are unfamiliar with 3-D design), and cut them loose on creating their designs. The bridge stand serves as a measure of roadbed accuracy, as it will only accommodate roadbeds with the following dimensions: 150mm (l), 25mm (w), and 2.5mm (h).
Print bridges and display on bridge stand as teams explain the design features of each bridge style and under which circumstances that particular style is used.
(Optional) Take the lesson to a dramatic, and destructive, conclusion by challenging students to design weight mounts and test maximum tensile strength. (See example Bridge Weight Mount file above)
Extension Activities:
-Increase the challenge of the assignment by requiring a maximum weight of each model, forcing students to not only design carefully, but to become familiar with the slicer program settings, and in a sense, operate within a budgetary constraint.
-Have a team that wants even more? Assign them to build a better bridge stand! Duration of Lesson
3-5 sessions for research and design 5-10 sessions for printing and redesign 3-5 sessions for testing models Preparation
This project can be a conclusion to, or part of, a larger unit on design, engineering, or bridges. Rubric and Assessment
See the included guidelines above for assessment recommendations.An additional requirement for project completion can include student's sharing designs on Thingiverse! References
Common Bridge Types:
http://www.pbs.org/wgbh/nova/tech/build-bridge-p3.html
Project: Bridge Building Project