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Radioactive age dating definition

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(They may draw microscopic organisms, such as bacteria, as if seen under the lens of a microscope.)Use narrow paper to create a frieze going around all four walls of your room, explaining that students will use the frieze to create their time line.Elicit from students that the time line is so long because Earth is estimated to be 4.6 billion years old.

During the history of the Earth there have been five mass extinctions.One of those mass extinctions eliminated the dinosaurs.Discuss what catastrophic events occurred to cause such a mass extinction.Discuss the differences between absolute and relative geologic dating methods and how they can be used together.The Earth has endured a great deal of weathering and erosion. Discuss the forces of nature that cause this erosion.They should note that, during Earth's first billion years, no life existed at all.

They should also recognize that most of the cards have been placed at the very end of the time line.

What does this show us about the history of human beings as residents of our planet?

(Students should conclude that we are relative newcomers, the earliest humans having appeared on Earth a mere 2 million years ago.) Students may also be interested to note that dinosaurs, mammals, and birds appeared on Earth around the same time (dinosaurs 240 million years ago, first mammals 225 million years ago, and first birds 200 million years ago).

Earth History Trivia Present this scenario to your students: You are the writer for the game show Catastrophic Events on Earth .

Your job is to create activities that will teach and review the catastrophic events that have shaped Earth.

Explain to the students that the scale is not exactly correct, but the numbers are so large that it will give them a good idea of relative time periods.