Ocean currents and overflows

This lesson is suited for middle to high school students in a natural science, physics, or geography class.

It is beneficial if students already have an understanding of the concept of density, but this can also be one learning outcome of this classroom activity.

This session is designed to stand on its own as is, but could also be included in instruction about ocean- and climate-related topics.

Students learn about the formation and origin of ocean currents, density, 3D ocean circulation, water mass transformation, overflows, and subsea topography (bathymetry). We also explain how researchers come to an understanding of the ocean (in this case through measurements and the discovery of an ocean current).

Students interpret horizontal maps and vertical sections of the ocean to understand the 3D ocean circulation. By conducting the experiment, they make and interpret observations, and transfer mechanistic understanding from the experiment to the real world. The students may formulate, test, and discuss hypotheses by modifying the experiment.

Students gain experience in following protocols to conduct laboratory experiments and in working in groups.

- Slides for presentation including teacher's notes, additional explanations, and experiment instructions
- Slides for presentation (student-friendly, without quiz answers and teacher's notes)
- "ABCD quiz sheet" - print 1 per student (instead, voting could be done using electronic tools such as menti, in which case you have to implement that yourself)
- Video introducing myself and my research, to be played during the presentation (ResearcherIntroduction.mp4)
- Backup video of experiment (OverflowExperiment.mov)
Teacher version of presentation (PowerPoint 2007 (.pptx) 12.1MB May22 24) 
Student version of presentation (PowerPoint 2007 (.pptx) 9.9MB May22 24) 
Student Handout to vote for quiz questions (Acrobat (PDF) 13kB May22 24) 
Video (MP4 Video 79.3MB May22 24) 
Backup video of experiment (Quicktime Video 609MB May22 24)

Detailed teacher's notes are provided in the "speaker notes" field of the slides in the teacher's version of the presentation.

The activity includes several quiz questions, where students "vote" for the correct response using "ABCD cards" (see supplementary materials), thus giving the teacher an indication of their understanding and thus a basis to decide on next steps in their teaching (e.g., repeat or further explain a concept, or move on).
The activity ends in a discussion about how modifications to the experiment would influence its outcome. Here, the teacher can observe how students argue, whether they refer to the correct concepts and use them directly, and whether they come to the correct conclusions.

- Popular science article on the discovery of the "underwater waterfall", including the experiment presented in this activity:

Semper, S., Glessmer, M.S., Våge, K., and Pickart R.S. (2022): How Warm Gulf Stream Water Sustains a Cold Underwater Waterfall. Frontiers for Young Minds. 10:765740. doi: 10.3389/frym.2022.765740. (https://kids.frontiersin.org/articles/10.3389/frym.2022.765740)

- Background reading about the scientific discovery (scientific article):

Semper, S., Pickart, R. S., Våge, K., Larsen, K. M. H., Hátún, H., and Hansen, B. (2020): The Iceland-Faroe Slope Jet: a conduit for dense water toward the Faroe Bank Channel overflow. Nature Communications. 11:5390. doi: 10.1038/s41467-020-19049-5. (https://www.nature.com/articles/s41467-020-19049-5)