Particle geometry effects on clustering dynamics: a study by primary school scientists*

Microplastic pollution, algae growth, and pollen deposition are natural examples of particle-laden fluid surfaces. Dynamics of these particles can be further complicated by the presence of waves, which is often the case in these natural settings. Two types of forces influence the movement of these particles, and the tendencies to cluster; capillary flotation forces, and capillary immersion forces. The former is due to gravity, and the latter force is dictated by the particle's wettability. The work discussed here is a collaborative effort between Portland State University (PSU) and The Portland Montessori School (TPMS) investigating the effect of particle size and shape on the clustering dynamics at the surface of an externally vibrating fluid. Students from TPMS were introduced to the fundamental fluid dynamic lessons that build the foundation for particle-laden fluid surface studies by PSU students. Motivation behind why PSU studies particle-laden fluid was shared with TPMS students. TPMS students concluded this instructional period by designing and performing particle-laden fluid experiments of their own, focusing on different particle sizes, shapes, wave frequencies and amplitudes. Analysis was performed by PSU with particle tracking software. The discussion of results was led by the observations of TPMS students aided by PSU.