Ranney School Science Department Chair Dr. Roxanne Spencer was selected to be a member of the American Association of Chemistry Teachers Chemistry & Sustainability Content Writing Team after submitting a lesson plan from her Chemistry Honors classes at Ranney School.
“We were extremely impressed with the lesson plan idea that [Dr. Spencer] submitted in her application, and are excited to have her as a member of the team,” said Monica Wixon and Jennifer Fees from the American Association of Chemistry Teachers.
“It is great that Dr. Spencer is doing such important professional work outside of Ranney, and that she is recognized by her academic peers,” said Head of School Dr. John Griffith. “Her outreach into the community of chemistry and broader STEM teachers provides amazing opportunities for Ranney. Our faculty are experts in their fields, and Dr. Spencer exemplifies that.”
"This summer, the AACT selected three teachers to each create a lesson plan related to the seven Sustainable Development Goals (SDG)
identified by the American Chemical Society (ACS) as foundational to the work of chemistry," said Dr. Spencer. "I wrote a multi-part lesson plan based on the seawater project from my Chemistry Honors classes that covers solution concentrations and properties, acid-base chemistry, and a passive solar still. The great thing about the content writing opportunities from AACT is the chance to share ideas with other chemical educators and receive meaningful feedback. These are valuable professional development opportunities."
Dr. Spencer’s lesson plan submission is outlined below:
My lesson plan idea relates to Sustainable Development Goal 6: Clean Water & Sanitation (and tangentially Goals 13 & 14). I have a seawater project that I have been refining in my Chemistry Honors classes for the past few years that I want to expand to include an engineering component.
To prepare, students read about their water footprint and drought conditions, then conduct lab analyses to determine the composition of artificial seawater (for example, calculate the molarity of different salts used in the recipe, use qualitative analysis to test for different ions in solution, measure conductivity and total dissolved solids). Colligative properties are introduced by having students measure the freezing and boiling points of seawater and deionized water. Finally, students will design a passive solar still to desalinate seawater.
Students will understand how solutes affect the properties of solutions, calculate molal and molar concentrations, write net-ionic equations and predict precipitates. Further, this project addresses HS-ESS2-5 (conduct an investigation of the properties of water) and HS-PS1-3 (conduct an investigation to gather evidence to compare the structure of substances).
In an extension activity, the buffering behavior of seawater is explored by monitoring the pH changes when dilute HCl and NaOH are added to deionized water and seawater. The effect of carbon dioxide absorption on the pH of seawater provides an illustration of buffer capacity, as the pH remains constant until the buffer is exhausted and pH declines.