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

Abstract

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 problemsolving 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.

Measurement report: A comparison of ground-level ice-nucleating-particle abundance and aerosol properties during autumn at contrasting marine and terrestrial locations

“…The lowest calculated n INP was reported at each 0.5 °C increment to prevent overestimation of n INP (Vepuri et al, 2021). Our HPLCgrade water is virtually INP-free at −25 °C (Wilbourn et al, 2023a). Data from WT-CRAFT have a minimum INP detection limit of 0.001 L −1 .…”

Measurement Report: A comparison of ice-nucleating particle and cloud condensation nuclei sources and properties during autumn at contrasting marine and terrestrial locations

“…Samples were diluted with HPLC-grade water 10 times or 100 times as needed, and the lowest calculated nINP was reported at each 0.5 °C increment to prevent overestimation of nINP (Vepuri et al, 2021). Our HPLC-grade water is virtually INP-free at -25 °C (Wilbourn et al, 2023). Data from WT-CRAFT has a minimum INP detection limit of 0.001 L -1 .…”

“…As well, the data from SGP can be compared with previously collected nINP(T) data as reported by DeMott et al (2015) for April-June 2014 and Knopf et al (2021) for October 2019, where it becomes apparent that the data collected in this study is comparable to data collected in the spring to early summer season 2014 and measurements of nINP(T) made by other online instrumentation in Fall 2019. 440 Although there are no previous studies reporting long-term nINP(T) at ENA, in Figure 4 we have compared the data to all other studies reporting nINP(T) in locations with strong Atlantic Ocean influence (Wilbourn et al, 2023;Figure S1 and references therein). The nINP(T) range for these studies is much larger than the range reported at SGP, potentially due to either difference in sample techniques or differences in nINP(T) between the seven locations.…”