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Types of Rocks
Layers of the Earth
Fossils
How Old is it?
Miscellaneous
100
This type of rock forms when magma cools.
What is igneous rock?
100
The thinnest layer of the Earth.
What is the crust?
100
The oldest fossils on record.
What is a stromatolite?
100
Scientists believe the Earth is this old.
What is 4.6 billion years?
100
This is a method paleontologists use to tell the age of fossils based on how deep they are in the Earth.
What are fossil layers?
200
This type of rock forms under intense heat and pressure inside the Earth.
What is metamorphic rock?
200
The thickest layer of Earth.
What is the mantle?
200
These are the one-celled organisms that scientists believe make up the earliest life forms on Earth.
What are prokaryotes?
200
This is the name of the radioactive substance that has a half life of 5,700 years.
What is carbon 14?
200
This is the percentage of radioactive material left in a fossil after 1 half life.
What is 50%?
300
This type of rock forms when bits of sediment from other rocks pile up in the bottom of the sea and they get packed and cemented together.
What is sedimentary rock?
300
The hottest layer of Earth.
What is the inner core?
300
This is a fossil that only lived in a certain time period.
What is an index fossil?
300
This is the exact age of a fossil.
What is absolute age?
300
According to our notes, the stegosaurus is an example of this type of fossil.
What is an index fossil?
400
This type of rock is formed when magma cools under the Earth's surface.
What is intrusive igneous rock?
400
The only liquid layer of Earth.
What is the outer core?
400
This is the name of a person that excavates fossils from the Earth.
What is a paleontologist?
400
This is how long ago scientists believe the first life forms appeared on Earth.
What is 3.6 billion years ago?
400
This is the name of the process that rocks go through as they change from 1 type to another.
What is the rock cycle?
500
This type of rock forms when lava cools on the Earth's surface.
What is extrusive igneous rock?
500
This is the name for the plates that make up Earth's crust.
What is the lithosphere?
500
This is something that can destroy fossils that have been under ground for a long, long time.
What is air?
500
This is how old the first fossils are that hint at the existence of complex life forms.
What is 1.8 billion years?
500
This is the what scientists use when they only know the age of rock layer in which they find a fossil.
What is the relative age?