This study investigated the impact of technology-based advance organizers (TBAOs) on the academic performance of 240 4th grade English learners (ELs) participating in a science class in School in the Park (SITP), a museum-school collaboration. While SITP provides a rich, hands-on learning environment, ELs face significant linguistic challenges in their ability to access the dense academic language and concepts provided in SITP's English only curriculum, thus negatively impacting ELs' engagement and learning. The TBAOs were designed in response to this issue. The study investigated two forms of treatment: TBAOs viewed on individual handheld mobile devices (HMDs), specifically iPods; and, TBAOs viewed as a whole class on DVD. The study utilized both qualitative and quantitative data sources, including a pre- and posttest, hands-on and performance-based assessments, as well as focus interviews. Results showed a "significant" interaction effect between group assignment, language status and application assessments, indicating ELs performed significantly better in the treatment groups. Students who used the HMD instead of the DVD or no treatment improved their total scores significantly on hands-on, performance-based measurements. Differences between treatment and control groups' performance on pre-/posttests approached significance. Furthermore, students reported TBAOs supported learning by introducing new material, introducing and reviewing daily academic vocabulary, and helping them anticipate behavioral and procedural expectations of hands-on activities. Classroom and museum educators reported an increase in the treatment groups' motivation and engagement. The study provided important implications in the use and power of learner-controlled technology in supporting ELs' linguistic and academic success.