APES 4

Core

The innermost layer of Earth; outer core is liquid, inner core is solid.

Mantle

Hot, semi-molten layer where convection currents move plates.

Crust

Earth’s thin, solid outer layer.

Lithosphere

The rigid outer layer of Earth made of the crust and upper mantle.

Tectonic Plates

Large pieces of the lithosphere that move due to mantle convection.

Convergent Boundary

Plates collide, forming mountains, volcanoes, or subduction zones.

Divergent Boundary

Plates separate, creating mid-ocean ridges and rift valleys.

Transform Boundary

Plates slide past one another, causing earthquakes.

Hotspot

A location where magma rises through the mantle to form volcanoes.

Soils & Earth Materials

Soil Formation

The creation of soil from weathering rock and organic matter.

O Horizon

Organic matter on the soil surface.

A Horizon

Topsoil rich in organic material and minerals.

B Horizon

Subsoil where minerals accumulate.

C Horizon

Weathered parent material.

Soil Texture

The proportions of sand, silt, and clay.

Porosity

The amount of space between soil particles.

Permeability

How easily water flows through soil.

Water-Holding Capacity

How much water soil can retain.

Atmosphere & Climate

Troposphere

Lowest layer where weather occurs.

Stratosphere

Layer containing the ozone layer.

Mesosphere

Middle layer where meteors burn.

Thermosphere

Layer where auroras occur.

Greenhouse Effect

Warming of Earth caused by greenhouse gases trapping heat.

Solar Radiation

Energy from the sun that drives climate.

Albedo

The reflectivity of a surface.

Atmospheric Circulation & Winds

Hadley Cell

Convection cell between 0°–30° that creates tropical rainforests and deserts.

Ferrel Cell

Convection cell between 30°–60° with variable weather.

Polar Cell

Convection cell between 60°–90° with cold, dry air.

Coriolis Effect

The deflection of moving air/water due to Earth’s rotation.

Trade Winds

Winds that blow east → west from 0°–30°.

Westerlies

Winds that blow west → east from 30°–60°.

Polar Easterlies

Winds that blow east → west from 60°–90°.

Weather & Climate Patterns

Weather

Short-term atmospheric conditions.

Climate

Long-term weather patterns.

Rain Shadow Effect

Dry conditions on the leeward side of mountains.

El Niño

A climate event where warm water shifts east, weakening trade winds.

La Niña

Opposite of El Niño; strong trade winds and cooler Pacific waters.

Water & Ocean Systems

Watershed

Land area that drains into a single body of water.

Runoff

Water flowing over land into water bodies.

Infiltration

Water soaking into the soil.

Upwelling

Cold, nutrient-rich water rising to the surface.

Thermohaline Circulation

The global ocean conveyor belt driven by temperature and salinity.

Natural Disasters

Earthquake

Sudden movement of Earth’s plates.

Tsunami

Large ocean wave caused by underwater earthquakes.

Volcano

Opening that releases lava, ash, and gases.