Cells and Homeostasis: Structured Talk

Today we revisited the concept of structured talk, with students thinking about and discussing why the membrane of a shell-less egg placed in distilled water ruptured, while a shell-less egg placed in corn syrup shriveled up.  After some private think/write time, students shared their understanding with their lab partner, comparing and contrasting their ideas.  Partners then shared with their table, after which the table groups represented their ideas visually on a white board.  By the end of the exercise, students had practiced structured talk and better understood the concept the water moves across the cell membrane toward the higher concentration of solute (a vocabulary word students will learn tomorrow).  After filling out a data capture tool for the UW, students then had time to analyze their graphs from yesterday and answer the following questions:

  • What patterns or trends do you see in your graph?
  • How did your choice of graph reveal patterns or trends in the data?
  • Given your understanding of the movement of water across a cell membrane, explain the egg mass results.
  • What questions do you still have?

Cells and Homeostasis: Graphing

Yesterday students analyzed the results of all of the Eggsperiment data from my five class periods.  They calculated the average change in egg mass for two or more experimental conditions and then graphed the results.  Each student is responsible for making their own graph, and the graph must include the condition of their egg, along with one or more relevant control conditions, or conditions that can used as a basis of comparison when writing the discussion section of their lab report.  The graph must include a title, labeled x-axis and y-axis with appropriately labeled increments, and a key explaining the groups on the graph.  Most students made a bar graph.