Connecting chemistry concepts with environmental context using student-built pH sensors

Educational research supports incorporating active engagement into K-12 education using authentic STEM experiences. While there are discipline-specific resources to provide students with such experiences, there are limited transdisciplinary opportunities that integrate engineering education and technological skill-building to contextualize core scientific concepts. Here, we present an adaptable module that integrates hands-on technology education and place-based learning to improve student understanding of key chemistry concepts as they relate to local environmental science. The module also supports disciplinary core ideas, practices, and cross-cutting concepts in accordance with the Next Generation Science Standards. We field-tested our module in three different high school courses: Chemistry, Oceanography and Advanced Placement Environmental Science at schools in Washington, USA. Students built spectrophotometric pH sensors using readily available electronic components and calibrated them with known pH reference standards. Students then used their sensors to measure the pH of local environmental water samples. Assessments showed significant improvement in content knowledge in all three courses relating to environmental relevance of pH, and to the design, use and environmental application of sensors. Students also reported increased self-confidence in the material, even when their content knowledge remained the same. These findings suggest that classroom sensor building and collection of environmental data increases student understanding and self-confidence by connecting chemistry concepts to local environmental settings.