APES UNIT 4

Tectonic Plates

Slabs of rock or lithosphere floating on top of the mantle.

Mantle

Molten, magma sea that tectonic plates float atop.

Earth's Core

Dense ball of nickel, iron, and radioactive elements that melts the mantle by decaying.

Divergent Boundary

Where tectonic plates move away from each other, often causing seafloor spreading.

Convergent Boundary

When two tectonic plates collide, leading to one plate being forced beneath another, often resulting in volcanic mountain ranges.

Transform Boundary

When two tectonic plates slide past each other in opposite directions, which can cause earthquakes.

Soil

A complex mixture of tiny particles of weathered rocks and organic material, containing pore space for air and water.

Weathering

The breakdown of rocks into smaller and smaller pieces.

Erosion

The movement of rock pieces by the wind and rain.

Igneous Rock

Rock formed by cooling, classified by silica content (e.g., granite).

Metamorphic Rock

Rock formed by intense heat and pressure, typically with high quartz content.

Sedimentary Rock

Rock formed by the piling and cementing of various materials.

Soil Texture

The percentage of sand, silt, and clay that a soil is made up of, which affects its characteristics.

Permeability

The ease/speed at which water can drain through soil.

Holding Capacity

The ability of soil to hold water for plant use.

Soil pH

A measure of the acidity of soil, which affects nutrient availability.

Nitrogen

One of the most critical nutrients for plant growth; often a limiting factor.

Phosphorus

Another essential nutrient for plant growth and a key limiting factor.

Troposphere

The layer closest to Earth where weather occurs and where the air we breathe comes from.

Stratosphere

The second layer of the atmosphere, containing a dense concentration of ozone that absorbs harmful UV radiation.

Mesosphere

The middle layer of the atmosphere, where gas molecules become less dense.

Thermosphere

The hottest layer of the atmosphere, receiving the most direct solar radiation.

Exosphere

The outermost layer of the atmosphere, merging with outer space.