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A Peek Inside the Lesson
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Inside the Earth
We live on the crust, Earth's thin rocky skin.
Below is the mantle: hot rock that flows very, very slowly.
In the middle is the core: a liquid outer core and a solid inner core of hot metal.
Earthquake-Safe Buildings
The crust is broken into giant pieces called plates.
When plates slip suddenly, the ground shakes: an earthquake!
Engineers design buildings with wide bases and cross braces so they don't fall.
Volcanoes
Magma is melted rock deep underground.
Magma rises and pressure builds up under a volcano.
When it bursts out, it's an eruption. Magma on the surface is called lava.
Lava cools into new igneous rock. Volcanoes build new land!
