Seafloor Spreading Lab | Ocean Crust Age & Plate Tectonics Inquiry

The Description

The ocean floor is disappearing. Not all at once, but over millions of years. Continental rocks can preserve billions of years of history, yet the oldest oceanic crust is only about 200 million years old. Where does the missing ocean floor go?

In this investigation, students tackle the mystery of Earth's young oceanic crust using evidence and a tectonic simulation. Rather than starting with definitions, they examine patterns and develop an explanation for how new seafloor forms, moves, and is recycled at plate boundaries.

What Students Will Do

• Use the discrepancy in continental and oceanic crust ages to frame a mystery.

• Examine evidence about seafloor age and plate motion.

• Use the Concord Consortium Tectonic Explorer model to test ideas and gather observations.

• Develop and revise explanations for ocean crust formation and recycling.

Why This Resource Is Different

A student may tell you that new crust forms at mid-ocean ridges and old crust subducts—then be unable to explain why that makes the ocean floor so much younger than the continents. I built the lesson around the age discrepancy so those separate facts have to become one explanation.

Students use age patterns and a tectonic simulation to test their ideas about where crust forms, moves, and disappears. Their job is to connect the model with the evidence, not just follow a simulation checklist. The question stays the same: Where did all that older ocean floor go?

What's Included?

• Nine-page student investigation as PDF and editable PowerPoint.

• Nine-page teacher answer key as PDF and editable PowerPoint.

• Updated teacher directions in editable Word format.

• Link inside the activity to the third-party Tectonic Explorer simulation.

The Details

Grades: Middle and high school Earth science. Standards shown on the investigation: MS-ESS2-2, MS-ESS2-3, HS-ESS1-5, HS-ESS2-1, and HS-ESS2-3. Materials: Printed or digital investigation and access to Tectonic Explorer. Format: PDFs, PowerPoint files, and editable Word teacher directions.