Printable Earth-Interior Models Worksheet | Grade 8 Science

This worksheet helps Grade 8 students compare two Earth-interior models, a uniform Earth and a layered Earth, by testing each against density calculations and seismic wave evidence. Students practice making predictions, controlling variables, and judging which evidence separates the models, then write evidence-based conclusions.

At a Glance

• Grade: 8 · Subject: Science
• Standard: Compare two Earth models using density and seismic wave evidence
• Skill Focus: Comparing Earth-interior models using predictions and discriminating evidence
• Format: 5 pages · 10 problems · Answer key included · PDF
• Best For: Evaluating competing models in Earth's Layers units
• Time: 35–45 minutes

What's Inside

Students work through 10 tasks across 5 pages: two density calculations, multiple-choice items, a prediction table, and short written explanations. The worksheet includes a model description box, an assumptions box, and a seven-station seismic data table. A 3-page answer key shows worked calculations and sample responses.

Skill Progression

• Guided practice: Part A has 2 calculation tasks with volume fractions and densities provided. Students multiply, add, and compare each result to the measured 5.5 g/cm³.
• Supported practice: Part B has 6 tasks using the data table. Multiple-choice items and a completion table prompt students to think about controls, model predictions, and composition versus mechanical layers.
• Independent practice: Part C has 2 tasks. Students choose the pair of discriminating evidence and critique a claim that the core is pure iron.

Together, the parts follow a gradual-release pattern: I Do, We Do, You Do.

Standards Alignment

No standard code is supplied for this worksheet. It supports the middle school science practices of developing and using models and engaging in argument from evidence, applied to Earth's internal structure. Add your district's code to lesson plans, IEP goals, or curriculum mapping tools.

How to Use It

• After direct instruction: Assign Parts A and B as guided classwork, then use Part C as an exit task.
• Before an assessment: Have partners complete the sheet and compare answers as a review.

Formative tip: as students fill in the prediction table, watch whether they decide what each model predicts before checking the data. Expect 35–45 minutes.

Who It's For

Grade 8 Science students in an Earth's Layers unit who can multiply decimals and read data tables. Offer a calculator and sentence starters to students who need support with written explanations. Pair it with a seismic wave diagram or an anchor chart on P and S waves.

The Grade 8 Science worksheet Comparing Two Earth-Interior Models teaches students to evaluate competing scientific models with evidence. Across 10 tasks on 5 pages, students test a uniform Earth and a layered Earth against a density calculation and a seven-station seismic data table, then decide which observations discriminate between the models. They practice identifying controls, such as using one earthquake for every station, and they judge whether a conclusion overreaches the data. The sequence moves from prediction to variable control to evidence evaluation, following the gradual release of responsibility described by Fisher & Frey (2014), in which teachers model, guide, and then release students to independent work. A three-page answer key supports quick checking. Teachers can use it to confirm that students connect S-wave shadows to a liquid outer core and to the layered model.