Integrated Science Teaching in Atmospheric Ice Nucleation Research: Immersion Freezing Experiments

This paper introduces hands-on curricular modules integrated with research in atmospheric ice nucleation, which is an important phenomenon potentially influencing global climate change. The primary goal of this work is to promote meaningful laboratory exercises to enhance the competence of students in the fields of science, technology, engineering, and math (STEM) by applying an appropriate methodology to laboratory ice nucleation measurements. To achieve this goal, three laboratory modules were developed with 18 STEM interns and tested by 28 students in a classroom setting. Students were trained to experimentally simulate atmospheric ice nucleation and cloud droplet freezing. For practical training, this work utilized a simple freezing assay device called the West Texas Cryogenic Refrigerator Applied to Freezing Test (WT-CRAFT) system. More specifically, students were provided with hands-on lessons to calibrate WT-CRAFT with deionized water and apply analytical techniques to understand the physicochemical properties of bulk water and droplet freezing. All procedures to implement the developed modules were typewritten during this process, and shareable read-ahead exploration materials were developed and compiled as a curricular product. Additionally, students conducted complementary analyses to identify possible catalysts of heterogeneous freezing in the water. The water analyses included: pH, conductivity, surface tension, and electron microscopy-energy-dispersive X-ray spectroscopy. During the data and image analysis process, students learned how to analyze droplet freezing spectra as a function of temperature, screen and interpret the data, perform uncertainty analyses, and estimate ice nucleation efficiency using computer programs. Based on the formal program assessment of learning outcomes and direct (yet deidentified) student feedback, we broadly achieved our goals to (1) improve their problem-solving skills by combining multidisciplinary science and math skills and (2) disseminate data and results with variability and uncertainty. The developed modules can be applied at any institute to advance undergraduate and graduate curricula in environmental science.