1. Geosphere (Solid Earth):
* Crust: The outermost layer, relatively thin and divided into oceanic and continental crust.
* Mantle: The thickest layer, composed of mostly silicate minerals and responsible for plate tectonics.
* Outer Core: Liquid layer composed primarily of iron and nickel, generating Earth's magnetic field.
* Inner Core: Solid, extremely hot ball of iron and nickel.
2. Hydrosphere (Water):
* Oceans: Cover about 71% of Earth's surface, containing the majority of Earth's water.
* Lakes, Rivers, and Groundwater: Represent a smaller proportion of Earth's water but are crucial for life.
* Ice and Snow: Found in glaciers, ice caps, and permafrost, representing a significant portion of Earth's freshwater.
3. Atmosphere (Air):
* Nitrogen (N2): Makes up about 78% of the atmosphere.
* Oxygen (O2): Makes up about 21% of the atmosphere, essential for most life.
* Argon (Ar): Makes up about 1% of the atmosphere.
* Trace Gases: Including carbon dioxide (CO2), methane (CH4), and ozone (O3), play important roles in climate and atmospheric chemistry.
4. Biosphere (Living Things):
* All living organisms: From microscopic bacteria to giant sequoia trees and blue whales.
* Ecosystems: Interactions between living organisms and their environment, creating diverse and interconnected webs of life.
5. Cryosphere (Ice):
* Glaciers and Ice Caps: Represent a large portion of Earth's freshwater and play a crucial role in climate regulation.
* Sea Ice: Frozen seawater that floats on the surface of the ocean, impacting ocean currents and climate.
* Permafrost: Permanently frozen ground, containing vast stores of organic matter and carbon.
Interconnectivity:
These spheres are interconnected and constantly interact with each other. For example, the atmosphere influences the climate and weather, which in turn affects the hydrosphere, biosphere, and cryosphere. The movement of tectonic plates in the geosphere can create mountains, volcanoes, and earthquakes, impacting all other spheres.
Composition by Mass:
* Iron: 32.1%
* Oxygen: 30.1%
* Silicon: 15.1%
* Magnesium: 13.0%
* Sulfur: 2.9%
* Nickel: 1.8%
* Calcium: 1.5%
* Aluminum: 1.4%
* Other Elements: Less than 1% combined
Understanding the composition of Earth is crucial for understanding its history, processes, and its role in the solar system.
