88th Annual Meeting (20-24 January 2008)

Sunday, 20 January 2008
Constant Proportions in the Ocean: A Constructivist approach to teaching seawater compostion
Exhibit Hall B (Ernest N. Morial Convention Center)
Andrew C. Muller, United States Naval Academy, Annapolis, MD
Concepts in ocean chemistry, such as chemical composition and salinity definitions can often be confusing and difficult to master for non-science majors in large introductory oceanography courses. In these large section classes where the number of students typically exceeds 80, instructors often tend to lecture rather than giving the students the opportunity to analyze real data.

This workshop will present a ‘hands on” approach to teaching Marcet's principle, better known as the principle of constant proportions using real data. In this exercise, participants will examine the major ion's contributions to the total salinity from several locations. From this data, students will be able to discover the ratio of these major ions, general salinity patterns in the ocean, how the term chlorinity came about to define salinity, and where Marcet's principle is not applicable.

Mastery of these concepts using real data leads to a deeper understanding of ionic residence time and steady state of the oceans.

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