Show:
Fossils
Relative Age of Rocks
Radioactive Dating
Geological Time Scale
Wild Card
100
What is a fossil?
The preserved remains or traces of living organisms
100
What is the relative age of a rock?
Its age compared to the ages of other rocks
100
What is a half life?
The time it takes for radioactive atoms to decay
100
Which was the longest era?
The Precambrian
100
Extinct
What is a type of organism that no longer exists
200
A fossil that shows the texture of a leaf is what type of fossil?
Cast Fossil
200
Number of years a rock has formed
What is it's absolute age
200
What happens during radioactive decay?
Atoms of an element break down to form atoms of another element
200
Name the 4 eras?
Paleozoic, Cenozoic, Precambrian, and Mesozoic
300
What type of rocks are fossils typically found in?
Sedimentary
300
Formation of igneous rock on Earth's surface
An extrusion
300
Elements that release particles and energy in a process, are described as
Radioactive
300
The key principal that guides scientist when they make inferences about Earth's past
The principle of Uniformitarianism
400
Describe the law of superposition?
Rock is older than the rock above it and younger than the rock below it
400
What is used to determine the relative age of rock?
Law of Superposition or Index Fossils
400
What do scientists often use to date rocks
Potassium-40
400
Geologist subdivide eras into
Periods
500
Name the 6 types of fossils
Molds, Casts, Petrified fossils, Carbon films, Trace, and Preserved Remains
500
How did the Grand Canyon form?
The flow of the Colorado river eroded and cut through rock layers.
500
Scientist's can determine Earth's age by radioactive dating, using samples from what?
Earth and moon rocks
500
What happened to earths continents 440 million years ago?
Early continents collided with what is now North America