Sources, Sinks, and Feedbacks

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SWBAT describe the relationship between atmospheric carbon dioxide, ocean surface levels and water vapor in terms of a positive feedback loop.

Big Idea

How does the amount of water vapor in the atmosphere effect atmospheric temperatures?

The Need for the Lesson

Students are familiar with linear cause and effect relationships but may not be familiar with feedback loops.  In this lesson I continue to use simulations from High Adventure Science. Students will use a model to learn about positive feedback loops in the context of climate change. In this case the positive feedback loop shows how climate change could spin out of control. This lesson challenges student thinking, helping them move beyond simple linear relationships to an understanding of complex interactions.

Investigation Preparation & Summary

5 minutes

In this lesson students will use models to understand how positive feedback loops amplifies climate change. (MS-ESS3-5 Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.)

The High-Adventure Science - Activity 3 Sources, Sinks, and Feedback presents to students a short written explanation along with simulations so students can manipulate variables to see the effect of change in a system. Boxes are provided for students answers. As the facilitator of this activity, I can run a report at any time to view student responses for all students, one student, all questions or one question. 

As students examine visual evidence via simulations they are asked questions designed to mentor them as they reflect on how changes in a feedback loop correlate to changes in the Earth's temperature. (SP1 Asking Questions and Defining Problems)

Students will manipulate variables using models to enhance their understanding of climate change and the impact of changes in a feedback loop. (SP2 Developing and Using Models)

Students will be changing variables to use models to make sense of the behavior of systems. (SP3 Planning and Carrying Out Investigations)

Students are actively engage in analyzing and interpreting data as each section of this lesson presents students with a simulation. Students are asked questions designed to guide them through interpretation of the simulations. (SP4 Analyzing and Interpreting Data)

Students are asked to explain the significance of data represented. (SP6 Constructing Explanations and Designing Solutions)

Questions encourage students to support their explanation using evidence from the visual images. (SP7 Engaging in Argument from Evidence)

Students communicate their evaluations variable changes via simulation by answering questions throughout the online activity using spaces provided. (SP8 Obtaining, Evaluating, and Communicating Information)

There are two methods to enroll your students in this activity. Enrollment is required to record student responses. One method is to enroll students yourself. Using this method, you enter student names and create their user name / password. I complete this process for one class. For all the other classes, I had the students self-enroll.

This lesson uses the High-Adventure Science activity - What is the future of Earth's climate? developed by Concord Consortium.

"Sources, Sinks, and Feedbacks" High-Adventure Science. Concord Consortium, 2015. Web. 23 May 2015.

Students in Action

45 minutes

Students in Action 

The following example of positive feedback yielding results is explained in the last section of Sources, Sinks, and Feedbacks. I use it to prime students minds to look for a feedback example within the lesson. In addition to exploring climate change, this is the first encounter my students have had with the concept of feedback loops. The strategy here is to activate their own knowledge of a simple feedback system (grades) so they are better able to connect to the more complex interactions caused by a positive feedback system in the context of climate change.       

What happens when you study for a test? You get a better grade, you know the answers.

How does that make you feel when you study and you get a good grade on your test? Great. Studying does help me remember the information.       

How likely are you to study for the next test? Very likely.

So can we say that when you receive positive feedback, then you continue to study therefore you continue to receive better grade? Yes

In this lesson you will examine what happens when variables other than simply carbon dioxide change within system. Think about how these variables are interrelated and what effect they have on the system. 

Sample Student Page - Sources, Sinks, and Feedbacks


If you need to clarify your understanding it is perfectly acceptable for you to confer with the scientists at your table group. You may also ask me any clarifying questions you have about the lesson. 

The website provides suggested answers to each question. I use these notes as I circulate around the room as students work. I like to work with my students one-to-one or small groups. The High-Adventure Science format also allows me to run a report at any time. The reports can be generated for all students or one student, all questions or a single question.

In the resources section you will find a Student Sample generated at the end of each section. My students select the print option and select PDF as their printer. The PDF responses are then shared with me via Google Drive.

In this video, I share one of the many report options available to educators on the High-Adventure Science site. This report helps me address the needs of my students.


Working with Small Groups of Students

As I look at the various reports from High Adventure Science, I note which students could use some direct instruction. Perhaps they missed the big idea or seem to be heading in the wrong direction and need some guidance. 

There is a table in my classroom I use for conferences. I ask a group of students to conference with me while the others are engaged in the lesson at hand. I let students know, that we are meeting to clarify the understanding of a particular point or question in the unit. The scope of the conference is such that we do not spend more than 5 minutes in discussion. The conference is focused on a very specific point of understanding. I may want to clarify, for instance, that in this unit the term feedback relates to a chain or cause and effect relationships not how someone feels about a particular issue. I limit the conferences to 1 or 2 per class period. 

The conferences are not just for those students need help but I may bring a group of students to the table to extend their thinking. What happens when... What are you wondering... What is the next question we need to tackle...

It is not uncommon that I meet with small groups students at various times throughout the year. During PBL (Project-Based Learning) students create a Need-to-Know list. Using students' Need-to-Know lists, I develop mini workshops or lessons to answer their questions. Only those students who require a workshop or mini lesson attend others go on with their work.

Whatever the reason for the conference, I limit the participants to 5 or fewer students. Once the number is larger than 5, I address topics with a whole class discussion.

So what are the other students doing during the conferences? They are working. We do this often and students know that the expectation is that they will continue on course during the class. After a conference, I circulate around the room checking on student progress. I ask questions about their work, "What did you learn from this map? Why is it important that we study..." 

Students know that I will be asking questions above and beyond the lesson questions and are prepared. This expectation has been set from practice since the beginning of the school year. It is not a problem with this unit especially because my students find the simulations to be challenging and engaging.

Another strategy that keeps students on task is self-selected seating. I let students select their seats and work with their friends admonishing them that friends do not let friends get into trouble. Students off task will be moved to a new location in the classroom. I find that for my students this is highly motivating.

One of my classes was recently observed by a vendor. My students were working independently on that day's lesson and he asked how students liked the format of the class. I suggested that he ask the students. The first group replied that they knew I trusted them to do their work. They liked that I showed them respect, helping when needed and allowing them to work together. 

Time, practice and understanding that being off task has consequences helps students self-manage during conferences.

Connecting the Learning

10 minutes

I really want to make sure students understand the concept of feedback loops. This short video from TEDEd is a great overview of both positive and negative feedback loops. 

I am sharing this video with students after the lesson as I want them to first construct their understanding of a positive feedback loop in the context of climate change then expand their understanding with examples of positive and negative feedback loops in nature.