Geology

Earth is made up of four distinct zones, or spheres, that each have unique characteristics: geosphere (land), hydrosphere (water), biosphere (living things), and atmosphere (air).

Geosphere

The geosphere is the region of Earth that contains the crust and core of the planet and everything within them. This includes all of the natural, lifeless matter from the rocks at the top of Mount Everest, to the sand at the bottom of the ocean floor, to the molten magma in Earth’s center.

Hydrosphere

The hydrosphere is all of the water on the planet, whether it is in liquid, solid, or gaseous form. Ninety-seven percent of the water on the planet is saltwater, while the remaining three percent is freshwater in the form of rivers, streams, groundwater, and glaciers.

Biosphere

If it is alive, it is part of Earth’s biosphere. This includes humans, plants, animals, bacteria, fungi, protists, and microorganisms, as well as any organic matter that has not yet decomposed.

Atmosphere

The atmosphere contains all of Earth’s gases, including the air we breathe. The atmosphere absorbs the heat from the sun that is reflected off Earth, controlling the temperature as well as weather patterns on the planet.