Study notes
Read the chapter, then drill it.
Each lesson maps to questions on the test. Mark a lesson when it feels solid — that tracks in your progress.
Earth's interior · tap a layer
Crust
5–70 km
Thin, rocky outer layer. Continental crust is thicker and less dense; oceanic crust is thinner and denser.
Systems
UnreadEarth's Spheres
Earth works as a set of overlapping systems: rock, liquid water, ice, air, and life. Most matching items on the test live here.
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Forces
UnreadShape, Density & Gravity
Earth is a sphere flattened a little at the poles. Gravity is the force that every object exerts on every other object — and denser objects pull harder.
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Layers
UnreadEarth's Interior
A thin crust, a thick mantle, a liquid outer core, and a solid inner core. Earthquake waves are how we know this without digging there.
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Shells
UnreadLithosphere & Asthenosphere
The lithosphere is the rigid lid. The asthenosphere is the plastic layer of rocks it rides on. These two names show up as both matching and fill-in.
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Surface
UnreadLandforms, Topography & Relief
Landforms are the features you can name. Topography is the shape of an area. Relief is how much the elevation changes. Iowa is plains.
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Shield
UnreadThe Magnetosphere
Earth's magnetic field makes a bubble around the planet. The test asks for two ways that bubble protects us.
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Origin
Unread4.6 Billion Years
Earth, the Sun, and the Moon formed about 4.6 billion years ago, along with the rest of the solar system.
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