Core Lab: Unraveling the History of Earth's Climate and Chemistry with Sediment Cores
Lesson Plan by Sandra Kirtland Turner and Jason Moore

The Core Lab is an approximately 10-day activity to introduce students to the idea that we can use sediment cores as recorders of the history of Earth’s climate and chemistry. In particular, we focus on sediment cores from the deep sea, since this represents the best archive for scientists studying Earth’s climate. An initial PowerPoint presentation introduces basic concepts in Earth History and provides examples of the types of questions scientists might ask about Earth’s past. Through the activity, students will build their own sediment cores to simulate different chemical and physical processes in Earth’s history. There are also 3 separate lab activities that accompany the steps of building the core. Students will learn that columns of sediment represent time and that properties preserved in the sediment can provide indirect evidence for some variable we want to measure.
  • Students will learn Earth’s climate has changed through time and that sediment cores record these changes.
  • Students will learn that sediments form layers at the bottom of the ocean.
  • Students will learn that physical and chemical reactions occurring in the environment leave traces in these sediments.
  • Students will learn about the global carbon cycle and how changes in it can be detected from sedimentary records.
  • Students will understand how oxidation-reduction reactions, acid-base reactions, and salinity all relate to Earth system processes.
  • Students will practice balancing chemical equations, stoichiometry, and calculating concentration and percent yield.
  • Students may have misconceptions about the idea of climate change in general. It is very important to be upfront about the difference between natural climate change through Earth’s history and anthropogenic climate change today.
  • Beyond that, students may have misconceptions about how we generate past climate records—for instance they may believe we have records from thermometers extending back hundreds of years, or they may think that tree rings and ice cores are the only sources of paleoclimate data. Try to ask students the ‘how’ question upfront: how do they believe we generate records of temperature and other climate variables from deep in Earth’s past?
  • Also, make sure that you clear up any confusion over the meaning of the word ‘core’. We are talking about cores of sediment—not the center of the Earth, not a processor on a computer, and not your abs!
  • The Core Lab is a multi-part activity that you can do over days or weeks. Ideally, you will allow at least two days between each activity in order to allow core sediments to settle and because this is necessary for a number of the accompanying lab activities. Remember that you can mix up the order of Days 4-9 between different classes so that students have to interpret cores that have a different order of events from their own.
  • Day 1: Introductory PowerPoint and Set-up.
  • Day 2-3: Settling Rates Lab.
  • Day 4-5: Oxidation of Iron Lab.
  • Day 6-7: Salinity of Saltwater Lab.
  • Day 8-9: Acidification of Water Lab.
  • Day 10: Final Evaluation.
  • The Core Lab includes a final activity that will take one or two 90-minute class periods.
  • This final activity requires students to interpret a sediment core made by another group of students using color as a proxy for past environmental conditions. Students will measure the thickness of each layer and describe its characteristics (color, texture, etc.).
  • Afterwards, students will make an Earth History timeline based on their core, which involves calculating “ages” for each sediment layer.
  • This is an activity was designed for 11th and 12th grade chemistry students. It might also be appropriate for an advanced Earth Science class if the teacher appropriately modifies and/or explains the relevant chemistry concepts (especially stoichiometry, balancing chemical equations, and other calculations).
  • The activity will take a minimum of ten 90-minute class periods (but is best if accomplished doing one activity per week or approximately 1.5 class periods per week).
  • Each group should have 3-4 students to ensure adequate participation.
  • For a chemistry class, it is best to complete this activity in the middle to later portion of the year, after students have been adequately introduced to major chemistry concepts (i.e. chemical equations, using the periodic table for calculations, basic lab safety and methods, etc.).
  • It is also helpful if students have previously reviewed some basics of Earth Science.
  • The introductory PowerPoint aims to do this, but supplementing it with additional activities on the carbon cycle may be beneficial (see SCC Activity from D. Richter and J. Corbin, “Carbon Cycle, Greenhouse Effect, and Ocean Acidification” Day 1 lesson).
  • The lab worksheets, journals, and final activity should be used for assessment purposes. Keys for all these documents are included in the Lab materials. Directions indicate that students make observations of their cores during each activity. Journal entries should be graded for completeness and attention to detail.
  • Remember that this activity has two key components: the qualitative description of the core and the quantitative methods in the supplementary labs.
  • We include detailed teacher notes emphasizing the purpose of each activity, listing materials, describing pre-class preparations, and providing tips for teaching the lesson. There are 5 separate documents for each of the major activities.
  • In addition, we provide detailed teacher copies of each lab activity with answers in red.
  • Finally, instructors may want to print out copies of the PowerPoint slides 19-24 (color optional) to provide for students during note taking for the Oxidation of Iron, Salinity of Saltwater, and Ocean Acidification labs. (Instructors may also want to print out PowerPoint slide 10 in the Introductory PowerPoint to allow students to take notes about the carbon cycle).
  • Students will review pertinent geological concepts for the Core Lab and set-up their cores. Refer to Teacher Directions Day 1. Review introductory PowerPoint with students entitled “Core Lab” slides 1-11. Use slides 12-14 for instructions on how to set-up sediment cores and make initial observations.
  • Students will learn how sediments layer at the bottom of the ocean and observe the settling rates of different sediment types. Refer to Teacher Directions Days 2-3. Use PowerPoint slides 15-18 for activity instructions, followed by a critical thinking activity that can be completed in one class period (if time permits).
  • Students will learn about the oxygenation of Earth’s atmosphere and learn the basics of oxidation-reduction reactions. Students will complete a lab involving the rusting of iron. Students will also add a rust layer to their cores. Refer to Teacher Directions Days 4-5 and watch the History Channel video “How the Earth was Made” on the rise of oxygen. Use PowerPoint slides 19-21 to illustrate the oxygenation of Earth’s atmosphere. Use the Teacher Key for the Oxidation of Iron Lab where students will predict the percentage of iron in a rust compound and then observe the rusting reaction over a few days.
  • Students will learn about the geologic clues for glaciations, including changes in sea level, salinity, and the presence of glacial dropstones in sediment cores. Students will complete a lab on the salinity of saltwater. Students will also add a salinity spike and a glacial dropstone layer to their core. Refer to Teacher Directions Days 6-7 and watch the History Channel video “America’s Ice Age.” Use PowerPoint slide 22 to illustrate how the formation of ice sheets influences ocean salinity. Use the Teacher Key for the Salinity of Saltwater Lab where students will progressively evaporate a saltwater solution and calculate the resulting change in salinity to see how falling sea level changes ocean salinity.
  • Students will learn about ocean acidification, including the impacts on organisms that build shells out of carbonate. Students will complete a lab on the reaction of acid with carbonate. Students will also generate a dissolution layer in their sediment cores. Refer to Teacher Directions Days 8-10 and use PowerPoint slides 23-24 to describe the chemical reactions involved in ocean acidification. Use the Teacher Key for the Acidification Lab where students will react acid with carbonate (both powdered and shell material).
  • Students will interpret a sediment core from another student group. Refer to Teacher Directions Days 8-10 and Final Core Lab Key for instructions and tips.

Core Lab on JOIDES Resolution


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Coal Mine in New Zealand
Lesson Specifics
  • Grade Level: 11-12
  • Time Frame: The activity will take a minimum of ten 90-minute class periods
  • Primary standards: Earth Science Standards 6c, 7b, 8b: "Investigation and Experimentation standard 1l"
  • Secondary standards: Chemistry standards 3a, 3d, 3e, 3f, 3g, 5a, 5b, 6a, 6d

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