Many students experience difficulties in solving applied physics problems. Researchers claim that the development of strategic knowledge (analyze, explore, plan, implement, verify) is just as necessary for solving problems as the development of content knowledge. In order to improve these problem-solving skills, it might be profitable to know at what time during problem solving is the use of instructional support most effective: before, during or after problem solving.
In an experiment with fifth-year secondary school students, one experimental group (n = 18) received hints during and worked examples after problem solving, and another experimental group (n = 18) received worked examples only after problem solving. Both groups used versions of a computer program to solve a variety of problems. The control group (n = 23) used a textbook. There was a pre-test to estimate the measure of prior expertise of the students in solving physics problems. The results of a problem-solving post-test indicated that the version of the program providing hints during and examples after problem solving was the most effective, followed by the version which only supplied examples afterwards. There was no difference in effect for students with more than average prior knowledge or less prior knowledge. (c) 2007 Elsevier Ltd. All rights reserved.