You are absolutely right! The Earth's lithosphere, which includes the crust and the uppermost part of the mantle, is indeed broken into huge moving slabs of rock called tectonic plates. These plates are driven by the movement of the mantle beneath them, a process known as plate tectonics.

Here's a breakdown of why and how this happens:

* Convection currents: Heat from the Earth's core creates convection currents in the mantle. Hotter, less dense material rises, while cooler, denser material sinks, creating a circular flow.

* Plate movement: These convection currents drag the tectonic plates along with them, causing them to move slowly across the Earth's surface.

* Types of plate boundaries: The interactions between these moving plates lead to different geological phenomena:

* Divergent boundaries: Plates move apart, creating new crust (e.g., mid-ocean ridges).

* Convergent boundaries: Plates collide, resulting in mountain formation, volcanic arcs, and subduction (one plate sliding under another).

* Transform boundaries: Plates slide past each other horizontally, causing earthquakes (e.g., San Andreas Fault).

The movement of these tectonic plates has shaped the Earth's surface as we know it, from the formation of mountains and oceans to the occurrence of earthquakes and volcanic eruptions.