What Are Tectonic Plates?
2. Fluidity
The land that we stand on is very solid and is mostly made from very hard rock. It takes special tools to dig into it and digging deep can be a real challenge. Beneath the thin crust, however, Earth begins to behave very differently. Instead of being hard and solid, it begins to act like a liquid.
Beneath the crust is the mantle, a thick layer of silicate rock that, on a geological scale, behaves in the same way as a viscous fluid. Beneath that is the outer core, which is a layer of molten, liquid nickel and iron. The final layer, the inner core, is made of solid nickel and iron.
