The process of designing an experiment is a difficult one. Students often struggle to perform such tasks as the design process places a large cognitive load on students. Scaffolding is the process of providing support for a student to allow them to complete tasks they would otherwise not have been able to complete. This study sought to investigate backwards-design, one form of scaffolding the experimental design process for students. Students were guided through the design process in a backwards manner (designing the results section first and working backwards through typical report components to the materials and safety sections). The use of reflective prompts as possible scaffold for metacognitive processes was also studied. Scaffolding was in the form of a computer application built specifically for this purpose. Four versions of the computer application were randomly assigned to 102 high school chemistry students and students were asked to the design of an experiment, producing a report. The use of backwards-design scaffolding resulted in significantly higher performance on lab reports. The addition of reflective prompts reduced the effect of backwards-design scaffolding in lower-level students.