The presented research study investigated the effects of computer-supported inquiry-based learning and peer interaction methods on effectiveness of learning a scientific concept. The stellar parallax concept was selected as a basic, and yet important in astronomy, scientific construct, which is based on a straightforward relationship of several components presented in a simple mathematical equation: d = 1/p. The simplicity of the concept allowed the researchers to explore how the learners construct their conceptual knowledge, build mathematical skills and transfer their knowledge beyond the learning settings. A computer-based tutorial "Stellar Parallax Interactive Restricted and Unrestricted Tutorial" ("SPIRUT") was developed for this study, and was designed to aid students' knowledge construction of the concept either in a learner-controlled or a program-controlled mode. The first investigated method in the study was enhancing engagement by the means of scaffolding for inquiry, which included scripted prompts and called for students' predictions and reflections while working in the learner-controlled or the computer-controlled version of "SPIRUT." A second form of enhancing engagement was through peers working cooperatively during the learning activities. The students' level of understanding of the concept was measured by (1) the number of correct answers on a conceptual test with (2) several questions that require knowledge transfer to unfamiliar situations and (3) their ability to calculate the stellar parallax and find distances to stars. The study was conducted in the University of Missouri among 199 non-science major students enrolled in an introductory astronomy course in the fall semester 2010. The participants were divided into two main groups: one was working with "SPIRUT" and another group was a control group and utilized a paper-based tutorial. The "SPIRUT" group was further divided into the learner-controlled and the program-controlled subgroups. Students' learning achievements were measured by two post- tests and compared to the students' results on a pre-test. The first post-test was administered right after the treatment with aim to measure the immediate effect of the treatment. The second post-test was administered eight weeks later and was aimed to elicit how much of the constructed knowledge students retained after the treatment. Results of the study revealed that students who learned the concept with "SPIRUT" constructed greater conceptual knowledge and were able to better transfer it to another situation while their mathematical skills were equally improved as those students who worked with the paper-based tutorial. It was also evident that there was no difference between students' performances after their engagement with the learner-controlled or with the program-controlled version of "SPIRUT." It was also found that students who worked independently constructed slightly greater knowledge than students who worked with peers. Albeit, there was no significant difference found of retention of knowledge after any type of treatment. [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.]