This goal is aligned with the National Science Education Content Standards for K-4 Physical Science (NRC, 1996). Specific NCSCOS objectives taught during the two-week set of lessons included the following: 3.03 Design and test an electric circuit as a closed pathway, including an energy source, energy conductor, and an energy receiver. 3.05 Describe and explain the parts of a light bulb. 3.06 Describe and identify materials that are conductors and nonconductors of electricity. 3.08 Observe and investigate the ability of electric circuits to produce light, heat, sound, and magnetic effects. 3.09 Recognize lightning as an electrical discharge, and show proper safety behavior when lightning occurs. This pilot study examined the following research questions: • Is PBL more effective than a direct instruction/experiential model in increasing content knowledge? • Does PBL result in increased retention of information over time? • Does PBL affect students’ stereotypical images of scientists? • Does PBL result in higher levels of time-on-task than a direct instruction/experiential model? • Does PBL facilitate the transfer of problem-solving skills to other situations?