Density Driven Flows
Summary
This hands-on lab activity is designed to teach students about how density differences, due to salinity, drive the flow of currents in the ocean. It also helps develop skills in performing and designing simple laboratory measurements; data entry, calculations and graph plotting in a spreadsheet; and comparing experimental data with a theoretical equation.
Key words: ocean circulation; density driven flows; salinity; ocean density; thermohaline circulation.
Key words: ocean circulation; density driven flows; salinity; ocean density; thermohaline circulation.
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Context
Audience
Introductory earth systems science course for majors and non-majors
Skills and concepts that students must have mastered
Key concepts that the students need to understand beforehand include: density, buoyancy and salinity in terms of the ocean; basics of ocean circulation and structure; and how to use spreadsheets for data entry and calculations.
How the activity is situated in the course
This activity is taught in a two-hour laboratory session, following a week of lectures and short activities on the ocean and its circulation.
Goals
Content/concepts goals for this activity
Understanding salinity and density driven flows in the ocean and thermohaline circulation. Performing and designing simple laboratory experiments, including data handling and collection, and the comparison of theoretical equations to experimental data.
Higher order thinking skills goals for this activity
Designing simple experiments to test hypotheses. Using experiments to replicate and measure natural phenomena. Comparing theoretical and experimental results.
Other skills goals for this activity
Working in groups, using spreadsheets, collecting accurate experimental data, following a method.
Description and Teaching Materials
The files here include a student handout, teacher's guide, blank data sheet and sample of the assessment used.
Density Driven Flows - Student Handout (Microsoft Word 2007 (.docx) 31kB May31 17)
Blank Results Sheet (Excel 2007 (.xlsx) 15kB May31 17)
Oceans Assessment (Microsoft Word 2007 (.docx) 65kB May31 17)
Density Driven Flows - Teacher's Guide (Microsoft Word 2007 (.docx) 451kB May31 17)
Density Driven Flows - Student Handout (Microsoft Word 2007 (.docx) 31kB May31 17)
Blank Results Sheet (Excel 2007 (.xlsx) 15kB May31 17)
Oceans Assessment (Microsoft Word 2007 (.docx) 65kB May31 17)
Density Driven Flows - Teacher's Guide (Microsoft Word 2007 (.docx) 451kB May31 17)
Teaching Notes and Tips
Tips for teachers, along with more details regarding some equipment are found in the Teachers guide. Safety guidelines can be found in both the student handout and teachers guide. The Oceans Assessment file shows the assesment related to this activity.
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Assessment
Assessment of the activity varies from year to year, but takes place in a follow-up assignment. For part 1 students are asked to complete the data analysis for their own experiments and some class data for comparison. For Part 2, they are asked to write up their experiment in a short formal report style (aim, method, results, discussion). See the Oceans Assessment file for more details.