Traditional high school physics instruction often comes across as a mere extension of the mathematics classroom to many of our students. Solving numerical physics problems using structures such as the GUESS method (given, unknown, equation, substitute, solve) doesn't help students with conceptual understanding. With the advent of physics education research (PER), problem solving in physics has taken a supporting, rather than starring, role, and modern PER-based physics instruction focuses chiefly on students having to write to explain their predictions and thought processes.