Considerable research has compared how students learn science from computer simulations with how they learn from "traditional" classes. Little research has compared how students learn science from computer simulations with how they learn from direct experience in the real environment on which the simulations are based. This study compared two college classes studying introductory oceanography. One class learned using an interactive computer simulation based on a dynamic, three-dimensional model of physical oceanography. The other class learned by spending a day on a research ship using scientific tools and instruments to measure physical properties of the ocean directly. In classes preceding and following the simulation or field experience, students performed the same exercises regarding currents and salinity, had the same instructor presentations, and did the same homework. The study found that the field experience helped contextualize learning for students with little prior experience of the ocean while the simulation made it easier for students to connect what they learned from it to other content they learned in class. These and other findings shed light on what computer simulations can and cannot help students learn, and what concepts are best learned in the real environment.