SPICE incorporates C2STEM, a computational modeling environment developed by Vanderbilt University. Students use a block-based programming interface to develop a computational runoff model and use it to investigate the runoff phenomenon for different surface materials, and test engineering design solutions that may combine the use of different materials to construct a playground. C2STEM is built using NetsBlox, a Snap! extension that supports the creation of custom programming blocks. These custom blocks make system variables such as hourly rainfall, water absorption by surface materials, and surface runoff explicit for students. In addition to the domain-specific constructs are computational blocks that specify mathematical relationships (e.g., arithmetic, algebraic) and computational constructs (e.g. conditionals, loops) to support model building. The underlying model is based on the Rational Equation, a widely-applied method in hydraulic engineering to estimate the peak discharge of a small watershed.

Students develop a model that provides a choice among seven surface materials. Each material has a unique cost, water permeability, and wheelchair accessibility factor. Student use the model they develop to test a variety of surface designs. The model computes the total runoff for a specified amount of rainfall at one hour time intervals.

A section of code from a computational water runoff model. Custom programming blocks decrease studentsâ€™ need to focus on syntax and highlight key scientific concepts that are essential to the model.