This exploratory mixed methods study addressed the types of gains students made when engaged in one of two forms of inquiry. Gains were measured on three levels: conceptual understanding, the process of scientific investigation, and use of practical reasoning skills. One hundred-thirty 8th grade students from a rural public school in East Texas participated in this study. Classes of students were randomly assigned to one of two treatment groups: guided inquiry or authentic student research learning. Non parametric statistical analysis and constant comparative qualitative analysis were used to triangulate pre-tests and post-tests, student journals, and student drawings to address the research questions. Findings support greater gains in conceptual understanding of domain specific content in a highly scaffolded guided inquiry. Further authentic scientific research learning was more effective for developing understanding of scientific investigation as a process and application of knowledge through practical reasoning skills.