AP Environmental Science Unit 4 - Earth Systems
Core
A dense mass of solid nickel, iron, and radioactive elements that release massive amounts of heat.
Mantle
A liquid layer of magma surrounding the core, kept liquified by intense heat from the core.
Asthenosphere
A solid, flexible outer layer of the mantle, beneath the lithosphere.
Lithosphere
A thin, brittle layer of rock floating on top of the mantle, broken up into tectonic plates.
Crust
The very outer layer of the lithosphere, the Earth's surface.
Divergent Plate Boundary
Plates move away from each other, often forming mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys.
Convergent Plate Boundary
Plates move towards each other, leading to subduction, mountain formation, island arcs, earthquakes, and volcanoes.
Transform Fault Plate Boundary
Plates slide past each other in opposite directions, often resulting in earthquakes.
Magma
Heated by the Earth's core, it rises towards the lithosphere, creating mid-oceanic ridges, volcanoes, and spreading zones.
Subduction Zone
Occurs when oceanic plates are forced underneath continental plates, leading to the formation of coastal mountains, volcanoes, and trenches.
Oceanic-Oceanic Convergent Boundary
One oceanic plate subducts underneath another, resulting in the formation of mid-ocean volcanoes and island arcs.
Oceanic-Continental Convergent Boundary
A dense oceanic plate subducts beneath a continental plate, leading to the formation of coastal mountains, volcanoes on land, trenches, and tsunamis.
Continental-Continental Convergent Boundary
One continental plate subducts underneath the other, forcing the surface crust upward and forming mountains.
Transform Fault Boundary
Plates sliding past each other in opposite directions create a fault, often resulting in earthquakes.
Ring of Fire
A pattern of volcanoes all around the Pacific plate.
Transform Faults
Likely locations of earthquakes.
Hotspots
Areas of especially hot magma rising up to the lithosphere, often resulting in the formation of mid-ocean islands.
Troposphere
The layer of the Earth's atmosphere closest to the surface where weather occurs and most of the atmosphere's gas molecules are found.
Ozone
A form of oxygen (O3) found in the troposphere that is harmful to humans and damages plant stomata, and contributes to the formation of smog.
Temperature Gradient
The change in temperature with distance from the Earth's surface, which determines the layers of the Earth's atmosphere.
Stratosphere
The layer of the Earth's atmosphere where temperature increases because the top layer is warmed by UV rays, similar to the surface of a pool.
Mesosphere
The layer of the Earth's atmosphere where temperature decreases because density decreases, making it the coldest place on Earth.
Thermosphere
The layer of the Earth's atmosphere where temperature increases due to the absorption of highly energetic solar radiation, making it the hottest place on Earth.
Exosphere
The outermost layer of the Earth's atmosphere, where atmospheric particles are so sparse that they can travel hundreds of kilometers without colliding with one another, gradually fading into outer space.
Coriolis Effect
The deflection of objects traveling through the atmosphere due to the Earth's rotation, which causes winds to move in curved paths.
Global Wind Patterns
The prevailing wind patterns on Earth, including the trade winds between 0-30 degrees (blowing from east to west), and the westerlies between 30-60 degrees (blowing from west to east).
Insolation
The amount of solar radiation (energy from the sun's rays) reaching an area, which depends on the angle of the sun's rays and the amount of atmosphere the rays pass through.
Albedo
The proportion of light that is reflected by a surface, with surfaces having higher albedo reflecting more light and absorbing less heat.
Climate
The long-term average weather conditions in a particular area, which is largely determined by insolation and geography.
Rain Shadows
The phenomenon where warm, moist air from the ocean rises and cools as it hits the windward side of a mountain, causing rain, while dry air descends on the leeward side, creating arid desert conditions.
El Nino
A pattern of shifting atmospheric pressure and ocean currents in the Pacific Ocean that leads to warmer and rainier conditions along the coast of South America.
La Nina
A pattern of shifting atmospheric pressure and ocean currents in the Pacific Ocean that leads to cooler and drier conditions along the coast of South America.
Gyres
Large ocean circulation patterns caused by global winds, with clockwise circulation in the Northern Hemisphere and counterclockwise circulation in the Southern Hemisphere.
Upwelling Zones
Areas of the ocean where winds blow warm surface water away from a land mass, drawing up colder, deeper water that is rich in oxygen and nutrients.
Thermohaline Circulation
The global circulation of the world's oceans, which mixes salt, nutrients, and temperature throughout, and plays a role in redistributing heat around the Earth.
El Nino Southern Oscillation (ENSO)
The pattern of shifting atmospheric pressure and ocean currents in the Pacific Ocean between South America and Australia/Southeast Asia, which oscillates between El Nino and La Nina conditions.