The purpose of this study was to examine the effects of captioning on undergraduate students' learning within a typical classroom environment. Based on guidelines associated with Universal Design as well as limitations imposed by classroom acoustics and noise levels, it was hypothesized that captions would increase students' recall and understanding of video-based information. Nine undergraduate introductory geology and geography classrooms were shown a 10-minute TED Talk about climate change. Five classes saw the video with captions. The other four classes saw the same video without captions. Students who saw the captioned video demonstrated significantly better comprehension and recall of information compared to students watching the same video without captions. Recommendations for further study are provided.