Skip to Content

Climate Change

Climate Change

DQCs: Keeling Curve & Biofuels

BACKGROUND: Today's students will be facing issues related to climate change over their whole lifetime. This set of questions and the associated active approaches focus on how humans are altering global carbon cycling, with particular emphasis on fossil fuel burning and the role of vegetation in carbon dynamics.

Faculty assume students understand these quite sophisticated ideas and others below, but research shows that they often do not. This is the hidden curriculum?.


HIDDEN CURRICULUM • Principled Thinking? Addressed

  • Principles?: Conservation of Matter? (the fate of organic carbon can be traced and must be kept track of in the 3 processes? listed below); energy and matter are related (energy cycles through ecosystems in conjunction with matter as chemical bond energy) but energy and matter are not interchangeable.
  • Processes: Generation? (photosynthesis); Transformation? (e.g. building of biomolecules within an organism), Oxidation? (respiration, decomposition)


  • Scale & Time: How the molecular/cellular/organismal processes associated with photosynthesis and respiration collectively contribute to ecosystem processes.


  • Forms & Representations: Ecosystem and Global Matter & Energy Flow; organic molecules as form of potential chemical energy.


The following 4 steps bring you through the process of selecting and using Diagnostic Question Clusters, interpreting student responses so you can focus on the concepts and thinking students appear to find most challenging, using active-teaching methods to help students make progress on these challenges, and finally gauging student improvement.

1. Select the DQC you want to use: the DQCs appropriate to use with these processes and topics are Keeling Curve & Biofuels. Both focus on the outcomes listed in the table above. For each question the specific outcomes are described in more detail on the DQC pages.

2. Administer DQC and make a Diagnosis. First give students the Diagnostic Questions you chose (e.g. in class, as homework - see DQC pages). Then look at their responses and try to figure out what these responses mean (diagnosis). In other words, identify students' unprincipled thinking concerning Climate Change. See diagnostic interpretations for Keeling Curve and Biofuels DQC's.

3. Use student active approaches to help students improve their understanding of the concepts and principled thinking. Once you figure out what your students need help with, you can use a variety of student-active approaches in class/as homework that should help them make progress. Below is a list of outcomes concerning Climate Change and associated active teaching approaches. These are examples you can use and modify as you wish.

4. Evaluate progress. Did students make gains on the outcomes you are focusing on here? To evaluate this, you can give them the same questions you used above (perhaps in a different way) or similar questions that get at the same outcomes (use Biofuels if you used Keeling Curve before).


Outcome: Students Better Understand

Active Teaching Approach

1. Keeling Curve and the importance of long term Ecosystem data.

Global CO2 Increase

2. Results of a Free-Air CO2 Enrichment (FACE) experiment in a pine forest.

Effects of Elevated CO2 on Trees

3. Biofuels: What they are and controversies over their effects on global C cycling.

Biofuels Increase CO2


4. Human activity impacts on C cycling.

Gallery Walk: Effects of Humans on Global C Cycle