  We describe a way to introduce physics high school students with no
background in programming to computational problem-solving experiences. Our
approach builds on the great strides made by the Modeling Instruction reform
curriculum. This approach emphasizes the practices of "Developing and using
models" and "Computational thinking" highlighted by the NRC K-12 science
standards framework. We taught 9th-grade students in a
Modeling-Instruction-based physics course to construct computational models
using the VPython programming environment. Numerical computation within the
Modeling Instruction curriculum provides coherence among the curriculum's
different force and motion models, links the various representations which the
curriculum employs, and extends the curriculum to include real-world problems
that are inaccessible to a purely analytic approach.
