Timeline of the Early Earth

Selby Cull
Washington University in St. Louis
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Students assemble timelines of the early evolution of Earth's atmosphere, lithosphere, biosphere, and hydrosphere by examining data from Archean rocks and minerals.

Used this activity? Share your experiences and modifications



I use this activity in intro Solar System classes, but it would also be appropriate for an introductory history of the Earth course

Skills and concepts that students must have mastered

  • planet formation mechanism
  • basic plate tectonics
  • rock cycle / rock types

How the activity is situated in the course

I use it as a stand-alone exercise.


Content/concepts goals for this activity

Concept Goals:
  • Interactions between lithosphere, atmosphere, biosphere, hydrosphere

Higher order thinking skills goals for this activity

By the end of this activity, students should be able to:
  • Construct a timeline of Earth Earth (4.5 - 1 Gya), including important events in the development of the atmosphere, biosphere, lithosphere, and atmosphere
  • Evaluate how the four spheres interact with each other; how each influenced the others during early Earth's evolution

Other skills goals for this activity

Description of the activity/assignment

Each student is assigned a sphere: Lithosphere, Atmosphere, or Biosphere. They will be responsible for constructing a timeline documenting events in the evolution of that sphere from 4.5 to 1.0 Gya. They are then given a set of cards, each with a photo of a rock/mineral from that time period, a summary of the research done on it and the conclusions various researchers have reached about that rock/mineral, and references. Students need to use the rocks to assemble their timeline. After each student is done, each student shares their timelines with the group, fills in the timelines for the three other spheres, and draws conclusions about how the three spheres interacted with each other as they evolved.

Teaching Tips

Adaptations that allow this activity to be successful in an online environment

In the classroom, I use groups and hang a giant map of the world on the wall; then tape the rock cards as posters near the map, connecting them by string to the place the rocks were found. This doesn't work as well online! But the cards can easily be distributed electronically.

Elements of this activity that are most effective

Having students be responsible for teaching the rest of the class about the evolution of their spheres in quite effective - as teachers, they're forced to articulate the timeline in a way that they wouldn't have to on paper.

Recommendations for other faculty adapting this activity to their own course:

Determining whether students have met the goals

I use a rubric that addresses the level of detail the students include in their timeline, whether they extract all the interesting information that is there to be extracted, and the quality of the connections they draw among the different spheres.

More information about assessment tools and techniques.

Teaching materials and tips

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