This hands-on activity explores the driving forces behind global thermohaline circulation.
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In order to effectively teach about the ocean conveyor belt, the PowerPoint presentation should be shown ahead of time so students are prepared for the content. Educator might want to have students think about ways to engage their audience in this material ahead of time - emphasizing how the ocean conveyor belt affects their own lives where they live.
Educator is encouraged to make the salty icebergs ahead of time. In some cases, using an submersible aquarium heater works well for an activity like this.
Assigning groups of students to experiment with different water mass scenarios works well - then have students present their results to their classmates before going to a wider audience.
The ocean conveyor belt transports heat throughout Earth's oceans and controls Earth's climate patterns.
Explanations of the factors that drive thermohaline circulation -- density gradients, surface air temperature, surface winds, ocean temperature variations, fresh water fluxes etc. -- are very simplified and only briefly explained. For an in-depth understanding of these factors, educator should explore additional materials.
Background material suggests that thermohaline circulation may have stopped or slowed down. In fact, scientific evidence exists that suggests that major freshwater fluxes, particularly at the end of the last major glaciation, slowed down the Gulf Stream; no scientific evidence exists that indicates a stopping of thermohaline circulation or the Gulf Stream.
Comments from expert scientist: Strong because it contains practice with prediction, observation, and explanation. Varies both temperature and salinity so students can differentiate between them and their separate effects on water density.
The hands-on activity is the core of this investigation. However, links to animations that show the same effect is provided for educators who are not equipped for the hands-on part of the investigation.
Students will need guidance to understand the implications of what they see in the experiment and how it relates to thermoahaline circulation. Applying this understanding to the global ocean conveyor belt will take some guidance and classroom discussions.
The lesson is carefully designed and provided as a downloadable pdf. A PowerPoint presentation accompanying the lesson is available.