Geologic Time Scale Lesson Plan

Instructor: Joanne Abramson

Joanne has taught middle school and high school science for more than ten years and has a master's degree in education.

Students can be easily confused by the multiple divisions of the geologic time scale. Using a short video and a hands-on group activity, this lesson plan aims to break down the geologic time scale and provide students with tangible references to better understand the concept.

Lesson Objectives

By the end of this lesson, students will be able to:

  • define and describe the purpose of the geologic time scale
  • differentiate between eons, eras, periods, and epochs
  • name and describe some of the major eons, eras, periods, and epochs


  • 1.5 - 2 hours

Curriculum Standards


Follow precisely a complex multi-step procedure when carrying out experiments, taking measurements, or performing technical tasks, attending to special cases or exceptions defined in the text.


Initiate and participate effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grades 9-10 topics, texts, and issues, building on others' ideas and expressing their own clearly and persuasively.

Key Terms

  • Geologic time scale (GTS)
  • Strata
  • Eon
  • Era
  • Period
  • Epoch


  • Rolls of adding machine paper or butcher paper cut into strips 2cm wide and 4.6m long
  • Meter sticks
  • Markers


  • Ask students the following series of questions and call on several to volunteer their answers:
    • How long does it take you to eat breakfast before school?
    • How long do you sleep at night?
    • How far away is the weekend?
    • How long until summer break?
    • How far away is graduation?
  • Point out that all the students responded, without thinking, in terms of a time scale: minutes, hours, days, months, and years. Explain that in this lesson they will be learning about a time line that measures on a much larger scale: from millions of years ago to thousands of millions of years ago.
  • Start the video Geologic Time Scale: Major Eons, Eras, Periods, and Epochs. Pause at 1:32.
  • Discuss the terms 'geologic time scale,' and 'strata.'
  • Return to the video, this time pausing at 4:02.
  • Discuss the terms 'eon' and 'era.' Review the Precambrian and Phanerozoic eons and the Paleozoic, Mesozoic, and Cenozoic eras.
  • Continue with the video. Pause at 5:09.
  • Discuss the terms 'period' and 'epoch.' Review the Triassic, Jurassic, Cretaceous, and Quaternary periods and the Eocene, Miocene, Pliocene, Pleistocene, and Holocene epochs.
  • Watch the video to the end.
  • Check for understanding by projecting the lesson quiz and completing it as a class.

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