Views of the Earth today Earth as a

Views of the Earth today Earth as a system

• The earth is a spherical shape • It supports a complex web of life. • The earth’s system has 4 major parts: – Atmosphere - air – Hydrosphere - water – Biosphere – living things – Geosphere – interior and rocks and soil

Atmosphere • The mixture of gasses and particles that surround the surface of the earth • Mostly nitrogen (78%) and oxygen (21%) • Also contains water vapor and carbon dioxide • The atmosphere starts at the ground and extends into space!

Hydrosphere • This is all of the water on earth • Oceans, lakes, glaciers, rivers, streams and underground water • Water covers ¾ of the earth’s surface • Only about 3% of this water is fresh water

Biosphere • The biosphere is all of life on earth. • Life on land, in the air, and in water. • Living organisms interact with the other parts of Earth’s systems. • Trees and large forests breath with the earth by absorbing carbon dioxide and releasing oxygen.

Geosphere • Geosphere is everything from the Earth’s surface inward. • Includes continents, islands, sea floor and everything below the surface of the Earth. • The geosphere is made up of 3 layers – Crust – Mantle – Core

Geosphere: Crust • Crust is the outermost layer. • This is where we walk on the land the floor of the oceans. • It is a thin rocky skin, much like the skin on an apple.

Crust • There are 2 types of crust: – Continental Crust • Makes up continents • Contains light colored rocks like granite • Floats high on the mantle – Oceanic Crust • Makes up ocean floor • Contains dense rocks like basalt • Thinner than continental crust

Geosphere: Mantle • Hotter and more dense than the crust. • The deeper you go inside the earth the more temperature and pressure increases. • Made of solid rock. • The mantle has 2 zones: – Lithosphere – Asthenosphere

Geosphere: Core • • Deep within the earth is the core. Made of mostly nickel and iron. Very dense, twice the density of the mantle. The core has 2 layers: – Outer is molten and responsible for Earth’s magnetic field – Inner is sold