  Identifying the relevant physics principles is a central component of problem
solving. A major goal of most introductory physics courses is to help students
discern the deep similarities between problems based upon the physics
principles so that they can transfer what they learned by solving one problem
to solve another problem which involves the same principle. We conducted an
investigation in which 251 calculus- and algebra-based introductory physics
students were asked explicitly in the recitation quiz to learn from a solved
problem and then solve another problem that has different surface features but
the same underlying physics principles. We find that many students were able to
discern the deep similarities between the problems. When the solved problem was
provided, students were likely to invoke the correct principles; however, more
scaffolding is needed to help students apply these principles correctly.
