This study investigated how question prompts and feedback influenced knowledge acquisition and cognitive load when learning Newtonian mechanics within a web-based multimedia module. Participants were one hundred eighteen 9th grade students who were randomly assigned to one of four experimental conditions, forming a 2 x 2 factorial design with the presence or absence of question prompts as one factor and types of instructional feedback as the other. With regard to knowledge acquisition, the findings revealed a significant main effect of question prompts and a significant interaction between question prompts and feedback. With regard to cognitive load, the results found a significant interaction between question prompts and feedback. Students who received problem-solving question prompts and corrective feedback achieved better performance and perceived less cognitive load. Implications for designing web-based science learning are discussed.