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Material

Reference Card: Inside the Earth & the Ring of Fire

A one-page reference card for Lesson 8 covering Earth's four layers (with real depths and temperatures), tectonic plates, and the Pacific Ring of Fire. Gives students the factual background to label diagrams and explain why earthquakes and volcanoes cluster at plate boundaries.

Earth isn't solid rock all the way down — it's built in layers, like a giant peach, with a thin cracked skin we live on.

Crust (5-70 km) Mantle (~2900 km) Outer core Inner core
Earth's four layers (not to scale).
LayerWhat it's likeSize / temperature
CrustThin, solid rock — where we live5–70 km thick
MantleHot, slow-flowing rock~2,900 km thick
Outer coreLiquid metal (iron & nickel)~2,200 km thick
Inner coreSolid metalabout 5,500°C