* Crust: This is the outermost layer, the one we live on. It's relatively thin, ranging from about 3-5 miles (5-8 km) under the oceans (oceanic crust) to around 25 miles (40 km) under the continents (continental crust).
* Mantle: This is the layer beneath the crust, extending down to about 1800 miles (2900 km). It's primarily composed of solid rock, but it behaves like a very viscous fluid over long periods due to intense heat and pressure.
Relationship: The crust is essentially a thin, rigid shell that rests upon the much thicker, more dynamic mantle. The mantle's movements drive plate tectonics, which in turn shape the Earth's surface, create mountains, and cause earthquakes and volcanic eruptions.
Think of it like this: Imagine a thin layer of skin on a much larger, soft fruit. The skin is the crust, and the fruit is the mantle. The skin's movements are influenced by the fruit's inner pressure and flow.
