Printable Evidence vs. Mechanism Worksheet | Grade 8 Science

This Grade 8 Science worksheet helps students explain why strong evidence that continents moved still did not tell scientists what moved them. Learners calculate seafloor spreading rates, test two competing models against data, and write a claim-evidence-reasoning response.

At a Glance

• Grade: 8 · Subject: Science
• Standard: No code supplied — students separate evidence that continents moved from an explanation of the force behind it.
• Skill Focus: Evidence of motion versus evidence of mechanism
• Format: 5 pages · 6 problems · Answer key included · PDF
• Best For: Extension after continental drift lessons
• Time: 45–60 minutes

What's Inside

The worksheet includes a conversions box, Evidence Packet A (five lines of evidence for movement), Packet B (three ideas about cause), and Data Table C of ocean-crust ages. Part A has two calculations, Part B has three competing-model problems, and Part C is one claim-evidence-reasoning response. The answer key runs 3 pages.

Skill Progression

• Guided practice: Items 1–2 supply the data and a conversions box, so students focus on unit work and model comparison.
• Supported practice: Items 3–5 ask students to pull evidence from the packets, work backward from basin data, and predict crust-age patterns.
• Independent practice: Item 6 is a full claim-evidence-reasoning response with only the packets as support.

The order follows gradual release: I Do, We Do, You Do.

Standards Alignment

No primary standard code was supplied for this worksheet. The tasks target a shared Grade 8 Earth science idea: evidence shows continents moved, and later ocean-floor data pointed to a mechanism. Add your local standard code when mapping it to lesson plans, IEP goals, or district curriculum tools.

How to Use It

• After direct instruction: Assign Parts A and B as independent work once students have seen Wegener's evidence. Expect 45–60 minutes.
• Across two class periods: Complete Part A in class, then assign Part C as a written exit task.

Formative tip: check Item 1 for skipped km-to-cm conversions. Students who skip that step usually miss every later rate.

Who It's For

Grade 8 Science students who know the basics of Pangaea and need practice reasoning with data. Support learners by working Item 1 together and pointing them to the conversions box. Challenge others to cite a second number in Part C. Pair it with a lesson or anchor chart on seafloor spreading.

“Continental Drift and Pangaea: Evidence Without a Mechanism” is a Grade 8 Science worksheet that teaches students to separate evidence that something happened from an explanation of why it happened. Across 6 tasks, students convert ocean-crust age data into spreading rates, test a plowing model against a ridge-spreading model, and write a claim-evidence-reasoning response explaining why Wegener's evidence for moving continents did not supply a cause. Ocean-floor data stand in for mid-1900s evidence. The sequence follows the gradual release of responsibility described by Fisher & Frey (2014), moving from constrained calculations to independent written reasoning. No standard code was supplied for this resource, so teachers can map it to local Grade 8 Earth science standards on plate tectonics. The 5-page file includes a 3-page answer key and works well as an extension after students have met the evidence for Pangaea.