# How do scientists use the knowledge of radioactive dating

Early methods relied on uranium and thorium minerals, but potassium—argon, rubidium—strontium, samarium—neodymium, and carbon—carbon are now of considerable importance. Uranium decays to lead with a half-life of 4. It is important that the radioactive isotope be contained within the sample being dated. Carbon is contained within plant material, but potassium, argon, and uranium are contained satisfactorily only within crystals. Igneous rocks are the most suitable for dating.

## Dating Rocks and Fossils Using Geologic Methods

In this activity, students gain a better understanding of radioactive dating and half-lives. Parent isotopes are represented by the M side up radioactive. Daughter isotopes are represented by the M side down stable. They then set aside stable isotopes During each trial, students record the number of radioactive parent isotopes and record this in a data table. Once all groups finish, each group records their info on the class decay table on the board and we calculate the averages of the class.

Once this info is calculated, students create a graph comparing the class average of parent isotopes to the number of half-lives. Modern Physics: Classroom Activity Grade Level: Middle Theme: Teach the Earth: Teaching Environments: Material on this page is offered under a Creative Commons license unless otherwise noted below. Your Account. Radioactive Dating: Paul, MN, based on an original activity retrieved from http: Paul Junior High School.

Summary In this activity, students gain a better understanding of radioactive dating and half-lives. Students will be able to explain what a half-life of a rock is. Students will have a more in-depth understanding of what radioactive decay is. Students will understand how scientists use half-lives to date the age of rocks. Relative Dating 2. Radioactive Dating 3.

Half-Lives 4. Isotope Concepts: This activity can be adapted for older students, but is used in an 8th grade earth science classroom. Class size can vary, but activity should be done in groups of Students should have the skill to set up a data table and a graph, however, if you want to use this activity with students that have not, you can provide them a template with that information. As far as mastery of content, this activity is done in our rocks and minerals unit. Students should have some prior knowledge of rocks and how they are dated.

This activity would also be easy to adapt when talking about half-lives within a chemistry course. Time Needed: Materials Needed: New information needed to be introduced with parent and daughter isotopes. Once students are in their groups, with supplies, and general directions are given, they are on their own for doing their runs. They will do this 8 times. Once they are finished with their 8 runs, they will record their data on the class data table which can be on the board. Once all groups data is on the table, you can calculate the average for each run and determine a class average.

Students should recognize each time the number should go down by appx half. Then students take the class data and create a graph comparing the number of parent isotopes to the number of half-lives. Once this is done, students have some post questions they are given that they should record in their science notebook. Adapted from: The first post question caused some confusion: Why didn't each group get the same results? A lot of the students said because they shook the containers differently This was a new activity we implemented last tear.

Radioactive decay and half-lives can be a very difficult concept for our 8th graders to grasp. They not only enjoyed this activity, but they really gained a better understanding of it as well. I have attached my rubric, this is what I use for assessment. Students graph, post questions, and data table will be looked at. Reuse Citing and Terms of Use Material on this page is offered under a Creative Commons license unless otherwise noted below.

Click More Information below. Kathleen Babich, South St. Provenance Created by the author of the page containing this file. Last Modified: April 23, Short URL:

## Geologists use radiometric dating to estimate how long ago rocks formed, and it to the quantity of stable daughter atoms in the rock, scientists can estimate the. Radiometric dating is used to estimate the age of rocks and other objects based on with just enough detail for a particular concept; visuals aid understanding.

Despite seeming like a relatively stable place, the Earth's surface has changed dramatically over the past 4. Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free. These changes typically occur so slowly that they are barely detectable over the span of a human life, yet even at this instant, the Earth's surface is moving and changing. As these changes have occurred, organisms have evolved, and remnants of some have been preserved as fossils. A fossil can be studied to determine what kind of organism it represents, how the organism lived, and how it was preserved.

Geologists use radiometric dating to estimate how long ago rocks formed, and to infer the ages of fossils contained within those rocks.

Radiometric Dating Activity. This hands-on activity is a simulation of some of the radiometric dating techniques used by scientists to determine the age of a mineral or fossil.

## Radioactive Dating: Looking at Half-Lives Using M&Ms

Carbon dating is used to determine the age of biological artifacts up to 50, years old. This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils like those of the dinosaurs alleged to be millions of years old. This technique is not restricted to bones; it can also be used on cloth, wood and plant fibers. Carbon dating has been used successfully on the Dead Sea Scrolls, Minoan ruins and tombs of the pharaohs among other things. Carbon is a radioactive isotope of carbon. The half-life of carbon is approximately 5, years.

## How Do Scientists Date Ancient Things?

Radiometric dating , radioactive dating or radioisotope dating is a technique used to date materials such as rocks or carbon , in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. Together with stratigraphic principles , radiometric dating methods are used in geochronology to establish the geologic time scale. By allowing the establishment of geological timescales, it provides a significant source of information about the ages of fossils and the deduced rates of evolutionary change. Radiometric dating is also used to date archaeological materials, including ancient artifacts. Different methods of radiometric dating vary in the timescale over which they are accurate and the materials to which they can be applied. All ordinary matter is made up of combinations of chemical elements , each with its own atomic number , indicating the number of protons in the atomic nucleus. Additionally, elements may exist in different isotopes , with each isotope of an element differing in the number of neutrons in the nucleus.

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Geologists often need to know the age of material that they find. They use absolute dating methods, sometimes called numerical dating, to give rocks an actual date, or date range, in number of years. This is different to relative dating, which only puts geological events in time order. Most absolute dates for rocks are obtained with radiometric methods.

## Radiometric dating

In this activity, students gain a better understanding of radioactive dating and half-lives. Parent isotopes are represented by the M side up radioactive. Daughter isotopes are represented by the M side down stable. They then set aside stable isotopes During each trial, students record the number of radioactive parent isotopes and record this in a data table. Once all groups finish, each group records their info on the class decay table on the board and we calculate the averages of the class. Once this info is calculated, students create a graph comparing the class average of parent isotopes to the number of half-lives. Modern Physics: Classroom Activity Grade Level: Middle Theme: Teach the Earth: Teaching Environments:

## Radioactive Dating

Love-hungry teenagers and archaeologists agree: But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes. Until this century, relative dating was the only technique for identifying the age of a truly ancient object. By examining the object's relation to layers of deposits in the area, and by comparing the object to others found at the site, archaeologists can estimate when the object arrived at the site. Though still heavily used, relative dating is now augmented by several modern dating techniques.

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Radioactive Dating