Ocean currents and overflows

Stefanie Semper, University of Bergen, Norway
Mirjam Glessmer, Lund University, Sweden
Author Profile
Initial Publication Date: May 23, 2024


We are researchers and teachers in physical oceanography. Here we provide a lesson plan including materials, to explore ocean currents and specifically "underwater waterfalls", i.e., overflows in the North Atlantic. We share editable slides that include a quiz, instructions for a hands-on experiment, and two videos (a video presentation by one of the researchers introducing themselves and their research, and a video of the experiment). We recommend conducting the experiment during the activity, but the video works as a backup. The slides are annotated with teacher notes to help with narration, background information, and conduction of the experiment.

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

Skills and concepts that students must have mastered

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.

How the activity is situated in the course

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


Content/concepts goals for this activity

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).

Higher order thinking skills goals for this activity

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.

Other skills goals for this activity

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

Description and Teaching Materials

- 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)

Teaching Notes and Tips

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.

References and Resources

- 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)