Here's why:

* Earth's Layers: The Earth has distinct layers: crust, mantle, outer core, and inner core. The crust is the outermost layer, and it's what we walk on.

* Types of Crust: The crust comes in two types:

* Continental crust: Thicker, less dense, and made up of mostly granite. This is what forms continents.

* Oceanic crust: Thinner, denser, and made up of mostly basalt. This is what forms the ocean floor.

* Sediments and Soil: A lot of the ground we experience is covered in sediments (like sand, silt, clay) or soil, which is formed from weathered rock and organic matter. These layers can be quite thick in some places.

So, what's underneath the sediments and soil?

* Bedrock: In many places, you'll find bedrock beneath the sediments. This is the solid rock that makes up the Earth's crust.

* Water: In some areas, especially near coasts and underground, you might find water tables or aquifers instead of bedrock.

In summary: While bedrock is a major component of the Earth's crust, it's not always directly beneath the surface. The ground we walk on can be covered by layers of sediment, soil, or even water.