Red Onions, Elodea, or Decalcified Chicken Eggs? Selecting & Sequencing Representations for Teaching Diffusion & Osmosis

Abstract

This study focused on the knowledge of six outstanding science students who solved an osmosis problem meaningfully. That is, they used appropriate and substantially accurate conceptual knowledge to generate an answer. Three generated a correct answer; three, an incorrect answer. This paper identifies both the accurate ana inaccurate conceptions about osmosis of each correct and incorrect solver. The investigation consisted of a presolving clinical interview, think-aloud solving of the problem, and retrospective report of the solving. Of the 12 accurate conceptions identified here, 2 were especially important in enabling these solvers to generate a correct answer. Of the eight inaccurate conceptions, either of two blocked a correct answer. Four, however, accompanied (and could therefore be concealed by) a correct answer. Teachers could use this information to make a meaningful solving of this problem accessible to more students and to identify more effectively students' inaccurate conceptions about osmosis. (Contains 23 references.) (Author) *********************************************************************** * Reproductions supplied by EDRS are the best that can be made * * from the original document. * *********************************************************************** That is, they used appropriate and substantially accurate conceptual knowledge to generate an answer.

Food Webs: Implications for Instruction

“…Teacher awareness of students' previous ideas related to food webs and how they make sense of these visual representations is essential for guiding deeper conceptual understanding. Diagrams are perhaps the most frequent type of representation, forming concrete models to support students' learning of abstract processes (Lankford & Friedrichsen, 2012). Biology concepts are frequently represented visually through different types of diagrams…”

Immersive 3D Experience of Osmosis Improves Learning Outcomes of First-Year Cell Biology Students

“…Understanding how molecules move across the cell membrane is a crucial concept in biology and is one that students need to master to acquire broader and more advanced concepts ( Sanger et al. , 2001 ; Lankford and Friedrichsen, 2012 ; Sung et al. , 2017 ).…”

“…Teachers have used different activities and approaches to teach osmosis and diffusion, such as coin-tossing exercises to show the random processes that are central to the process ( Haddad and Baldo, 2010 ), red onions and decalcified chicken eggs to depict net water movement ( Lankford and Friedrichsen, 2012 ), and dialysis bags and potato slices to show the process on a macro scale ( Odom et al. , 2017 ).…”

“…Understanding how molecules move across the cell membrane is a crucial concept in biology and is one that students need to master to acquire broader and more advanced concepts (Sanger et al, 2001;Lankford and Friedrichsen, 2012;Sung et al, 2017). Knowledge of diffusion and osmosis is required to understand normal and abnormal cellular functions, as well as life processes, such as water movement into the roots of a plant; photosynthesis; cellular respiration; and the swelling of brain cells in cerebral edema.…”

“…Teachers have used different activities and approaches to teach osmosis and diffusion, such as coin-tossing exercises to show the random processes that are central to the process (Haddad and Baldo, 2010), red onions and decalcified chicken eggs to depict net water movement (Lankford and Friedrichsen, 2012), and dialysis bags and potato slices to show the process on a macro scale (Odom et al, 2017). In addition, with advances in technology, there is increasing use of multimedia simulations and dynamic visualizations to complement the traditional methods used to teach osmosis and diffusion (Rundgren and Tibell, 2009;Odom et al, 2017;Sung et al, 2017).…”