Feedback loops make an appearance in almost any environmental science curriculum. In AP Environmental Science, feedback loops show up in topic 1.11 (ENG-1.D.2) in the context of food chains and webs. In IBESS, systems take on a greater role, with feedback loops being introduced in topic 1.2 (2024 curriculum), and continue throughout as a major theme of the course. Feedback loops can be used to illustrate abstract relationships between many of the complex abiotic and biotic interactions we cover in our courses. One of the most effective and impactful way to introduce this concept is to pair it with the concept of climate change.
There are many ways teachers have found to include feedback loops in a variety of concepts, but here is my favorite strategy by Megan Thaler.
Materials:
Technology to display a video and examples
Scratch paper
Printed or laminated (optional) feedback loop station cards (slides 5-11) and place around the room.
1. Ask students to fold a piece of lined paper into 12 sections and to write the following. I use a doc cam.
2. Briefly introduce what feedback loops are using this google slide deck. Do not spend more than 2-3 minutes explaining. You want spend most of your time showing them how (next step).
3. Play this TED Talk video via Youtube. Stop after each example presented and draw with them under the doc cam. I like to demonstrate and draw the first couple with them. By the third they get the hang of it and can try on their own. Draw it quickly after they try to confirm if they were on the right track or not. Emphasize that Negative does not mean ‘bad’ in this context and Positive does not necessarily mean ‘good’,
(For students struggling with the concept of a positive feedback loop being an amplification and a negative feedback having ‘returns’ to equilibrium, I take a couple of these examples and show how each would ‘feel’ if I were to take steps forward for amplifications of an effect and take steps backwards for returns. I stand up and narrate “more deforestation….” *step forward* “…means more erosion…” *step forward* “…means even less trees growing…” *step forward* “…and even more erosion.” At this point I am halfway across the room. I also show them how a negative feedback loop may look. Any negative feedback loop has a ‘backwards step’, but it does not necessarily mean that every negative feedback has to stop where it started. This demonstration is useful for the next step.)
4. At this point, release students to walk around and complete the seven climate change examples placed around the room. I like laminating my stations and taping them to cabinets so students have to physically get up to see them. Emphasize that everyone will have their own style of drawing the feedback loops, that it is a means to an end to identify the loop as negative or positive.
5. After about 20 or so minutes, review answers with students (“Was number 1 negative or positive? What was #2?”). Sometimes I will pause to review the trickier or more emphasized topics such as why the ocean currents are changing, what permafrost is, or a review of the definition of albedo.
6. As a check for understanding, throw this image onto your projector and ask kids if they think it is a positive or negative feedback loop. It is very fitting!
Climate change is a depressing topic for many students. After this activity I usually follow up with a lab or activity demonstrates how we (as humans) can help feed the natural negative feedback loops that will return climate back to equilibrium. Among my favorites include this carbon sequestration lab by Kristi Schertz or (for AP teachers) the AP Classroom alternative Lab 19: An Investigation of Carbon Sequestration in Urban Trees.
How do you incorporate feedback loops in your classroom?
(Cover image from Explain XKCD)
