Decoding Ice CoresâIsotopic AnalysisâHow warm was the Earth in the past?

Notes from our reviewers

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• Teaching Tips
  Additional resources are included at the bottom of the student/teacher guide; these could be used to help introduce or extend the activity. One consideration if using pennies would be to find pennies that have minimal extra "gunk" stuck to them, as this would impact the mass of the pennies and therefore the lab's data. This resource could be utilized in a unit on climate change, specifically a unit directed at how scientists use data to create models and make inferences. Depending on the amount of time teachers want this activity to take, they could have each student/group collect data from all 11 stations, or they could have each student/group collect data from just a few stations and then share that data as a class. A multi-media approach may also help students better understand how we use the ocean as a standard for oxygen mass and the connection between oxygen atomic mass and climate. The activity may also pair well with videos or a lesson on determining the age of the ice.
• About the Science
  This resource helps students understand how scientists can use proxy data (relative isotopic mass of water molecules in ice cores) to make inferences about past temperatures/climate and make predictions about future temperatures/climate. Students complete a lab where pennies dating from different time periods are used as a model to mimic water molecules with differing oxygen isotope concentrations. Students are asked to identify variables, make measurements (mass), organize their data into tables, and analyze and graph that data. They will next discuss their findings and the similarities and differences between their investigation and that of scientists in Antarctica. These labs do a good job in supporting students' understanding of how we are able to make inferences about past climate conditions using proxy data. Understanding the basics of isotope geochemistry is not covered well in the introduction. Students may need more background or this activity may be better suited after a lesson on basic atomic structure and the periodic table. Passed initial science review - expert science review pending.
• About the Pedagogy
  This resource includes a student lab where students work individually or in small groups. The teacher guide is useful, but a bit hard to follow. For instance, lab set up instructions come after lab procedure instructions. Student worksheets are provided in the Google Doc; teachers can make a copy to edit and differentiate accordingly. Student worksheets offer pre-lab and post-lab analysis questions aimed at supporting student inquiry.
• Technical Details/Ease of Use
  Student worksheets are provided as Google Docs; teachers can make a copy if they wish to edit the document, or print it as is. It is also important to note these docs may not be stable over a long period of time. Teachers need to obtain pennies from different time periods (pennies pre and post 1982 have different masses), or need to purchase washers. It is important that the material used to modify the mass is standardized (i.e., do not just add glue or clay to the pennies), in order to properly represent the different isotope masses. Teachers will need to print student worksheets. Be sure to click "open as Google Doc" after clicking "download lab" as the images block text in the first view. Teachers will need to take some time to familiarize themselves with the lab, obtain materials, and set up the 11 stations that represent 11 different ice core samples. Teachers should set aside approximately one hour in order to do this prep.