Igneous
What happens when magma or lava cools and hardens?
It forms igneous rock.
How do pieces of rock, minerals, and plants become sedimentary rock?
They build up in layers and are pressed and glued together over time.
Can a rock be metamorphic if it has melted?
No
How long does the rock cycle usually take?
Millions of years
Which layer of sedimentary rock is the oldest?
The bottom layer
How do igneous rocks form?
Magma or lava cools and hardens
What do sedimentary rocks sometimes contain that can tell us about the past?
Fossils
What two types of rock do metamorphic rocks start out as?
Sedimentary
What are strata?
Layers in sedimentary rock
What would finding a marine fossil on top of a mountain mean?
That area was once underwater
What size crystals form when magma cools slowly underground?
Large
Name the 3 main things that are contained in sedimentary rock.
Rock pieces
Nutrients
Plants
What changes a rock into metamorphic rock?
Heat and pressure deep inside Earth
What is erosion?
The movement of rock pieces from one place to another
What type of rock contains fossils?
Sedimentary
What size crystals form when lava cools quickly?
Tiny
What two things break rock down into smaller pieces to make sedimentary rock?
Wind and water
What type of rock does marble form from?
Limestone
What is weathering?
The process that breaks rocks into pieces
Name 3 general things that rocks are used for.
Building
Tools
Art
Name one example of an igneous rock.
Basalt
Pumice
Obsidian
Granite
What processes press layers together and help form sedimentary rock?
Compaction and cementation
What is one thing that slate can be used for?
Roof tiles
What happens during deposition?
Rock pieces are dropped in new places
What do scientists use igneous rock for?
Dating items