Service-learning and undergraduate research experiences are high-impact practices that have become more common in the sciences, but the benefits of short-term experiences have not been thoroughly investigated. The purpose of this study was to compare within-semester gains for students in a short-term service-learning (SL) or short-term research project (RP) in terms of students’ (i) motivation to learn biology, (ii) scientific literacy, (iii) perception of the relevance of biology to their lives, and (iv) learning gains associated with course learning outcomes. The impacts of brief service-learning and research project experiences were compared using direct and indirect assessments, including qualitative coding of open-ended response questions and quantitative analysis of exams and Likert-type items. We found few differences between students in the two projects regarding their changes in motivation (both slightly negative), scientific literacy (both gains), and their ability to connect biology to their lives (both gains). Emergent themes revealed that both projects influenced students' plans for future research and service-learning. Both projects helped students build relationships; however, RP students built relationships with classmates, while SL students built relationships with community members. The positive experiences highlight the need for engaging science students through service-learning in addition to research.