Here's a breakdown:

* Lithosphere: This is the rigid, outermost layer of Earth. It includes the crust (the top layer we live on) and the uppermost part of the mantle.

* Asthenosphere: This is a semi-solid, partially molten layer of the upper mantle. It's like a very thick, viscous fluid.

Think of it like a plate (the lithosphere) floating on top of a very thick, gooey substance (the asthenosphere). This "floating" is what allows the lithosphere to move, causing tectonic plates to shift and drift, leading to earthquakes, volcanoes, and mountain formation.