Saturday, February 18, 2017
Exhibit Hall (Hynes Convention Center)
Joan Horvath, Nonscriptum LLC, Pasadena, CA
3D printers have created a dilemma for teachers. They, or their students, can just download things to print from existing databases of objects, but that is not a lot different from just buying a model from a catalog. Alternatively they can take on the task of learning a computer-aided design program so that they can create their own objects, but this can be time-consuming. We decided that for math and science at least there was a middle way: the creation of “starter sets” of parameterized models in the open-source programming language OpenSCAD (available at www.openscad.org.) We discovered that creating such models was harder than it had first appeared, particularly because many classic textbook illustrations all use the same cartoonish 2D projections of a concept. For example, we wanted to create accurate trusses for students to explore compressive and tension forces. However, an ideal truss is supposed to rotate freely at its joints, which is difficult to achieve with 3D printing alone. It became a complicated philosophical discussion to think about what it meant to create a 3D flexible version of an idealized 2D truss. We further realized there are two broad classes of math or science model: visualizations and experiments. Visualizations are models that will not be varied and that show a physical system (or, perhaps, something very big or very small, like molecular structures.) A lot of existing models that hobbyists have made fall into this category. Experiments, though, are where we feel the technology has particular promise. In this case a base model is parameterized, and the student or teacher using it can explore a discipline by chaning parameters. For example, we encoded a set of airfoil cross-sections and wing parameters which allowed the student to create a wide range of realistic wings to use in explorations of aerodynamics. The model also had an option to add a wind tunnel sting to the back of the wing, so that it could be used to do simple force measurements. Our original set of models was created as part of a book project; we are exploring how to expand this vision. Obviously it has particular promise for tactile learners, who may not aways do well from the traditional ways of teaching science with markers on a whiteboard. We have also started a community for teachers of visually impaired students to request model creation help from others looking for a good science project to do.