A large number of undergraduate students have naive understandings about the processes of Diffusion and Osmosis. Some students overcome these misconceptions, but others do not. The study involved nineteen undergraduate movement science students at a Midwest University. Participants' were asked to complete a short answer (fill-in the blank) test, and if possible participate in a follow-up interview. The researcher constructed short answer test that consisted of a three-tier structure that required students to generate answers, diminishing the influence found in two-tiered instruments such as "recognition" of correct answers and test taking skills More importantly, each level built upon knowledge demonstrated in the previous tier; this allowed the researcher to determine where the breakdown occurred. Part one of the test consisted of 9 questions that prompted students to provide short answer definitions. Part two of the exam consisted of 7 questions that contained two parts. The first question required a true or false answer and the second required a brief explanation. The final part of the test consisted of 12 questions related to three scenarios. After each question students were also asked to record how confident they were with their answers on a three point scale. This helped to determine whether students had "confidence" in their answers, or if they were just guessing. A total of three students agreed to participate in audio-recorded interviews. Descriptive and correlational data was used in the analysis of this study. This data included: (1) test; (2) interview; (3); Point biserial correlation coefficients; (4) Cronbach's alpha correlation coefficients; (5) Kendall's Tau-b correlation coefficients; (5) and error pattern analysis Evidence from this study demonstrates that students do have misconceptions, about the processes of diffusion and osmosis. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]