Interactive surfaces are increasingly common in museums and other informal learning environments where they are seen as a medium for promoting social engagement. However, despite their increasing prevalence, we know very little about factors that contribute to collaboration and learning around interactive surfaces. In this paper we present analyses of visitor engagement around several multi-touch tabletop science exhibits. Observations of 629 visitors were collected through two widely used techniques: video study and shadowing. We make four contributions: 1) we present an algorithm for identifying groups within a dynamic flow of visitors through an exhibit hall; 2) we present measures of group-level engagement along with methods for statistically analyzing these measures; 3) we assess the effect of observational techniques on visitors' engagement, demonstrating that consented video studies do not necessarily reflect visitor behavior in more naturalistic circumstances; and 4) we present an analysis showing that groups of two, groups with both children and adults, and groups that take turns spend longer at the exhibits and engage more with scientific concepts.

In this paper we describe visitor interaction with an interactive tabletop exhibit on evolution that we designed for use in natural history museums. We video recorded 30 families using the exhibit at the Harvard Museum of Natural History. We also observed an additional 50 social groups interacting with the exhibit without video recording. The goal of this research is to explore ways to develop "successful" interactive tabletop exhibits for museums. To determine criteria for success in this context, we borrow the concept of Active Prolonged Engagement (APE) from the science museum literature. Research on APE sets a high standard for visitor engagement and learning, and it offers a number of useful concepts and measures for research on interactive surfaces in the wild. In this paper we adapt and expand on these measures and apply them to our tabletop exhibit. Our results show that visitor groups collaborated effectively and engaged in focused, on-topic discussion for prolonged periods of time. To understand these results, we analyze visitor conversation at the exhibit. Our analysis suggests that social practices of game play contributed substantially to visitor collaboration and engagement with the exhibit.

In this paper, we present the DeepTree exhibit, a multi-user, multi-touch interactive visualization of the Tree of Life. We developed DeepTree to facilitate collaborative learning of evolutionary concepts. We will describe an iterative process in which a team of computer scientists, learning scientists, biologists, and museum curators worked together throughout design, development, and evaluation. We present the importance of designing the interactions and the visualization hand-in-hand in order to facilitate active learning. The outcome of this process is a fractal-based tree layout that reduces visual complexity while being able to capture all life on earth; a custom rendering and navigation engine that prioritizes visual appeal and smooth fly-through; and a multi-user interface that encourages collaborative exploration while offering guided discovery. We present an evaluation showing that the large dataset encouraged free exploration, triggers emotional responses, and facilitates visitor engagement and informal learning.