Earth's Layers
What is the outermost layer of Earth?
The Crust
What are the three main types of rocks?
Igneous, sedimentary, metamorphic
What are minerals made of?
Elements or compounds
What is the breaking down of rocks called?
Weathering
Which horizon is mostly made of decomposing leaves, twigs, and organic matter at the surface of the soil?
The O horizon
Which layer is made of liquid metal?
The outer core
Which rock forms when lava or magma cools?
Igneous
What is the color of a mineral’s powder called?
Streak
What is the movement of sediments called?
Erosion
What name is given to the layer commonly called “topsoil” where many plant roots grow and organic matter is mixed with mineral soil?
The A horizon
Which layer is the thickest?
The mantle
Which rock forms from layers of sediment being pressed together?
Sedimentary
What test determines how easily a mineral can be scratched?
Hardness test (Mohs scale)
What is the dropping or settling of sediments called?
Deposition
Which horizon is known as the “subsoil,” where materials like clay and minerals leached from above tend to accumulate?
The B horizon
What two metals make up most of the core?
Iron & nickel
Which rock forms when heat and pressure change existing rock?
Metamorphic
What property describes how light reflects off a mineral’s surface?
Luster
Name one agent of erosion.
Water, wind, ice, or gravity
What horizon is made up of weathered parent material, and is often right above bedrock?
The C horizon
What causes Earth’s magnetic field?
Movement of liquid metal in the outer core
What process can change any rock into any other rock over time?
The rock cycle
Name one way to identify a mineral besides color.
(Any of these: streak, hardness, luster, cleavage, fracture, magnetism)
How do weathering and erosion work together to shape Earth’s surface?
Weathering breaks down rock; erosion moves the pieces
What horizon is the solid rock layer under all the soil layers and not actually considered “soil”?
The R horizon (bedrock)