Unit 4

The land part of the Earth’s crust. It’s thicker and less dense than oceanic crust

The ocean part of the Earth’s crust. It’s thinner and denser than continental crust

The layer of hot, mostly solid rock underneath the Earth’s crust. It has convection currents that move the tectonic plates

The layer of liquid iron and nickel underneath the mantle. Scientists believe it is responsible for Earth’s magnetic field

Places where magma rises up from the mantle, creating volcanoes

Where tectonic plates meet. There are three types of plate boundaries: divergent, convergent, and transform

Where two plates slide past each other, often causing earthquakes

Where two plates collide

Where two plates move apart

Rock that forms when magma or lava cools and hardens

Rock that forms when sediments (like sand, pebbles, or shells) are compacted and cemented together

Rock that has been changed by heat and pressure

The rock that breaks down to form soil

The shape of the land (hills, valleys, etc.)

The process by which sediments are dropped in a new location

When nutrients are washed out of the soil by water

Porosity: The amount of space between soil particles

How easily water can flow through soil

The process of water soaking into the ground

A measure of how much carbon dioxide is released by living things in the soil. More respiration usually means healthier soil

How compact the soil is. More compact soil has less space for air and water

The amount of nitrate in the soil. Nitrate is a nutrient that plants need, but too much of it can leach into water

How well soil particles clump together. Good aggregation helps prevent erosion

When one object orbits another object (like Earth orbiting the sun)