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Bean decay lab . How do scientists use radioactive decay or absolute age to date fossils and artifacts ? How accurate do you think absolute dating would be? Give me a time frame. .
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How do scientists use radioactive decay or absolute age to date fossils and artifacts? • How accurate do you think absolute dating would be? Give me a time frame.
In this lab you are going to start with 100 beans. The beans represent Uranium atoms. For this lab you will model how radioactive dating works. • Count your atoms and make sure you have 100 • Place them in the box with all them on the white facing side. • Close the lid and shake the box • Open the box and count the atoms that have the black side up. After you finish remove them from the box and graph your results. • Repeat steps 3 and 4 until you get down to 1 or 0.
Problem: How many half-lives does it take Uranium to turn into lead Hypothesis: Materials: Beans, container with lid
Bean Decay lab Questions • Was your hypothesis correct? Has your definition of “decayed” changed? If so how? • At the end of each half-life (trial) , approximately what percentage are the atoms “decaying”? • 3. Does the amount of time you shake the box affect the outcome? • 4. Do the number of atoms you start with affect the outcome? Explain. For example if we only used 50 beans, would my data be different • 5. How do you think absolute dating differs from relative dating?
Look at the class master graph… • Why doesn’t everyone have the same results? • What can this tell us about the accuracy of half lives?
How old is old? • Scientists use several strategies to determine age of rocks and fossils. • Relative Age: age of an object compared to another- “I am older than you” • Absolute Age: actual age of an object or how long ago an event occurred by using radioactive dating. • Radiometric Dating: measures the absolute age of an object using time or the rate of decay for a radioactive element (located in fossils) in a rock
So what is Radioactive? • Radioactive is the breakdown of an elements isotope/atom. • Isotope/atom – matter with different amounts of neutrons or electrons • The rate of change or breakdown of elements is measured in Half-lifes. • Stable = not decayed • Unstable= decayed
Try This!!If Carbon has a half life of 5730 years; how much will be left after 3 half lives?