The Challenges of Fluid Density (Petrosino and Mann 2017)

The following is some research that has been conducted over the past few semesters with preservice STEM teachers' understanding of fluid density. Density is a concept taught in almost all elementary, middle, and secondary schools across the nation and is a central concept in the physical sciences. It is also historically a difficult concept to understand since it involved mass as well as volume and is multidimensional. Even more difficult in many respects is fluid density (fluids in fluids). The fluid density of a liquid is determined by its consistency with respect to its state in temperature and pressure. The temperature and pressure play an important role individually in determining the density of a fluid. Therefore, oil based drilling fluids and water based drilling fluids have different densities. In this paper a doctoral student and myself explore some of the especially difficult ideas embedded within fluid density and some efforts we have made to address this conceptual understanding for preservice teachers (n= 140).

1. Paper Title: The challenges of fluid density.

2. Authors and author affiliations
Dr. Anthony J Petrosino is a learning scientist and is an associate professor in the Department of Curriculum and Instruction at The University of Texas at Austin.
Michele J Mann is a doctoral candidate in the program of STEM Education within the Department of Curriculum and Instruction at The University of Texas at Austin

3. Abstract < 250 words

Teacher’s understanding of science concepts must be deeper than just factual knowledge. They need to understand how the facts are connected and relate to the natural world. Weather, ocean currents and tectonic movement are all phenomena listed in the NGSS. While understanding density of fluids within fluids is not directly mentioned in the NGSS, students need to understand fluid density in order to explain the common yet complex phenomena mentioned above. We extended a familiar science activity of making a density column in order to help the teachers understand the expectations of NGSS. Having an understanding of the causes of the phenomena is critical for teachers. We found when students don’t understand density it increases their tendencies to substitute concrete or active causal factors, such as weight or force. We issued to our teachers the following challenge: “Make a density column with these four mystery liquids.” As our students were in the process of determining the correct order to add the liquids, we noticed they confuse mass and viscosity with density. In light of the expectations of the NGSS, we need to change the way we are preparing our teachers. They need time and space to practice connecting the concepts in practice. Therefore, we need to help them connect the concepts to past experiences and providing time to reflect and revise. The teachers need to develop a mindset as a lifelong learner powered by their reflections and drive to help students understand science.

4. Keywords: up to 8
Professional Development, Density, Next Generation Science Standards, Science Concepts, Fluid Density, Domain Knowledge