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Radioactive and relative dating 2 way random sex chat

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.

*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.

For example, most limestones represent marine environments, whereas, sandstones with ripple marks might indicate a shoreline habitat or a riverbed.

Return to top The study and comparison of exposed rock layers or strata in various parts of the earth led scientists in the early 19th century to propose that the rock layers could be correlated from place to place.

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.

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.

In this activity, students begin a sequencing activity with familiar items — letters written on cards.

Once they are able to manipulate the cards into the correct sequence, they are asked to do a similar sequencing activity using fossil pictures printed on "rock layer" cards.

Scientists also use direct evidence from observations of the rock layers themselves to help determine the relative age of rock layers.

Specific rock formations are indicative of a particular type of environment existing when the rock was being formed.

198 comments

  1. Most people think that radioactive dating has proven the earth is billions of years old. Yet this view is based on a misunderstanding of how radiometric dating works.

  2. This is an activity that students will use M&Ms to gain a better understanding of radioactive dating and half-lives.

  3. Sep 08, 2012 This video presents the basics of relative age dating the principle of superposition for middle school science.

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