Relative dating vs absolute dating worksheet

Locally, physical characteristics of rocks can be compared and correlated.On a larger scale, even between continents, fossil evidence can help in correlating rock layers.Sequencing the rock layers will show students how paleontologists use fossils to give relative dates to rock strata.Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history.If certain fossils are typically found only in a particular rock unit and are found in many places worldwide, they may be useful as index or guide fossils in determining the age of undated strata.By using this information from rock formations in various parts of the world and correlating the studies, scientists have been able to establish the geologic time scale.INTRODUCTION Scientists have good evidence that the earth is very old, approximately four and one-half billion years old.Scientific measurements such as radiometric dating use the natural radioactivity of certain elements found in rocks to help determine their age.

Teaching about Earth's history is a challenge for all teachers.The Law of Superposition, which states that in an undisturbed horizontal sequence of rocks, the oldest rock layers will be on the bottom, with successively younger rocks on top of these, helps geologists correlate rock layers around the world.This also means that fossils found in the lowest levels in a sequence of layered rocks represent the oldest record of life there.*Life Science: Fossils indicate that many organisms that lived long ago are extinct.Extinction of species is common; most of the species that have lived on the earth no longer exist.

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