Lesson 2: Geologic Time Scale and Earth’s History
Duration of Days: 4
Lesson Objective
Students will be able to interpret the geologic time scale, describe major eons, eras, and periods, and explain how Earth’s history is organized over deep time.
-How is Earth’s history divided into eons, eras, and periods?
-What major events define different parts of the geologic time scale?
-How do scientists use rock layers to organize Earth’s history?
-Why is Earth’s history considered “deep time”?
-How does the geologic time scale help us understand changes in life and environments?
-Geologic time scale
-Eon
-Era
-Period
-Epoch
-Stratigraphy
-Rock strata
-Fossil record
-Relative time
-Index fossils
HS-ESS1-4 – Use evidence from rock strata and fossil records to explain Earth’s history.
NGSS Crosscutting Concepts
-Patterns
-Cause and Effect
-Stability and Change
-Scale, Proportion, and Quantity
-Students will interpret geologic time scale charts and timelines.
-Students will analyze fossil and rock layer data to place events in chronological order.
-Students will construct explanations using evidence from stratigraphy and fossil records.
Students will explore how scientists organize Earth’s 4.6-billion-year history using the geologic time scale. Students will analyze major events in Earth’s history and interpret how rock layers preserve evidence of past environments and life.
Activities may include:
-Creating geologic time scale timelines
-Ordering events using fossil and rock evidence
-Analyzing rock strata diagrams
-Identifying major Earth history events
Purpose: Develop understanding of deep time and Earth’s historical structure using evidence-based sequencing
DOK Level: 2–3 – Skill/Concept to Strategic Thinking
-Understanding Earth’s history as context for human existence
-National Park geological formations and fossil sites
-How geologic time informs natural resource exploration
-Earth’s history is short compared to human time
-All fossils exist at the same rock layer
-Time is evenly distributed across rock layers
-Geologic time is based on human history divisions
-Color-coded timelines
-Chunked geologic time charts
-Graphic organizers for eons/eras/periods
-Partner sorting activities
-Scaffolded reading of time scale information
-Geologic time scale labeling
-Timeline construction
-Exit tickets on Earth history sequencing
-Short response questions
-Geologic time scale charts
-Rock layer diagrams
-Fossil record visuals
-Timeline construction materials