TERC, in partnership with the Boston Museum of Science, will investigate deaf and hard-of-hearing museum visitors' use of App-based signing math and science dictionaries delivered on the iPod Touch. The project is employing a mixed-methods design to study how and the extent to which family visitors, ages 5-12+, and classroom visitors in grades K-12 use the dictionaries to access and communicate about exhibit content and engage in activities. Study participants will visit one of two preselected exhibit areas and do several activities that have Word Lists posted on the activity panels. The Word Lists include key terms for the activity that are also included in at least one of the dictionaries. They will then do several activities that do not have Word Lists posted. A coin toss will be used to randomly assign the first group of visitors to a starting Word List condition. The second group will then begin with the alternate Word List condition. From this point on, subsequent groups will continue to alternate the starting point. Data collection will include observation, videotaping, interviews, and surveys. Results of the study will be disseminated through a report of findings, presentations and publications.