The author investigated the interaction effect of immersive virtual reality (VR) in the classroom. The objective of the project was to develop and provide a low-cost, scalable, and portable VR system containing purposely designed and developed immersive virtual learning environments for the US Army. The purpose of the mixed design experiment was to compare lecture-based and immersive VR-based multimedia instruction, in terms of declarative knowledge acquisition (i.e. learning) of basic corrosion prevention and control with military personnel. Participants were randomly assigned to the control group (N = 115) or investigational group (N = 25) and tested immediately before and after training. The author accessed learning outcomes from the pre-exam and post-exam scores and VR system usability from exit questionnaires. Results indicate that both forms of instruction will increase learning. VR-based did produce higher gain scores and there was a statistically significant interaction between instruction type and time.