This study explored the use of a dichotomous key as a scaffolding tool in the museum setting. The dichotomous key was designed as a scaffolding tool to help students make more detailed observations as they identified various species of birds on display. The dichotomous key was delivered to groups of fifth and seventh graders in two ways: on a mobile platform and by museum educators. Data was collected in the forms of pre- and post-testing and observations to compare the two methods. Findings suggest the Mobile Dichotomous Key (MDK), developed by educators at the Bean Life Science Museum at Brigham Young University, was equally as effective as a teacher (museum educator) in assisting students in a learning activity designed to improve or develop scientific observation skills. While both groups' outcomes were the same, data from observations made during the learning activity showed that there were significant differences in the experience for the students. Students using the MDK were more engaged, could work at their own pace, and were more likely to work with their peers than students working in groups led by a museum educator. In contrast, students in the educator-led group were able to receive immediate feedback during the learning activity, as museum educators were able to make assessments and answer questions or expand the learning experience. A feedback mechanism is suggested for a future version of the Mobile Dichotomous Key app.