Oklahoma Science 6.ESS1.4

Science6th GradeEarth’s Place in the Universe

The Standard

Construct a scientific explanation based on evidence from rock strata for how the geologic time scale is used to organize Earth’s geologic history.

Oklahoma Academic Standards for Science (2026)

Teacher's field guide

What Students Need to Do: Students use rock layers and fossils to work out which events happened first. They explain how scientists use this evidence to divide Earth’s history into named spans of time.
What Mastery Looks Like: Given a rock column and a geologic time chart, students put the layers in order and match fossil clues to broad spans of time. They point to specific layers and fossils to support their explanation.
Common Misconceptions: Some students think the top layer is oldest, or that every layer represents the same amount of time. Others think a fossil gives an exact date or that every site preserves a complete record.
How to Assess It: Give students a three-layer diagram with a trilobite at the bottom, a dinosaur in the middle, and a horse at the top, plus a labeled era chart. Ask: “Which layer is oldest, which era fits the dinosaur layer, and what evidence supports your answers?”

Lesson moves

Stack colored paper strips with printed fossil cutouts, then match the layers to a simple geologic time chart.
Show two rock columns with the same fossil and ask, “Which layers likely formed around the same time, and what supports that claim?”
Give pairs rock-layer cards and an era chart; have them order the cards and place each in an era using fossil clues.
Project a highway road-cut photo; have students mark the oldest visible layer and explain what the layers can and cannot reveal about age.

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