Todays Objective How Do Scientist Figure Out A Numerical Age For Rocks Do Now Using the diagram to the right what is the difference between relative dating and absolute dating What is a jiffy ID: 1022852
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1. Absolute Dating Earth History
2. Today’s Objective: How Do Scientist Figure Out A Numerical Age For Rocks? Do Now:Using the diagram to the right what is the difference between relative dating and absolute dating?
3. What is a jiffy unit of time used in computing equal to 1/100 second; any small unit of time
4. Absolute Age : - Using numbers and units to tell exactly when an event occurred. - This can be done by using fossils.Relative Age ONLY shows the order, or sequence, of events. It is a comparison
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6. Basic Atomic StructureBohr’s Model of the atomPROTONS are positive and in the nucleus NUETRONS are neutral and in the nucleus ELECTRONS are negative and orbit around the nucleus.
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8. Isotopes The number of protons identify the element.- Chemical elements have several forms. - Same number of protons and different Number of neutrons.
9. EXAMPLE Stable Element, Carbon-12: -6 Protons -6 NeutronsUnstable Element, Carbon-14: -6 Protons -8 Neutrons Carbon-14 will change into a stable element Nitrogen – 14
10. Radioactivity is the spontaneous decay of certain unstable atomic nuclei.
11. Radioactive DecayContinues at a regular rate (not affected by outside factors). The rate is not effected by any physical or chemical reactions The first (unstable) isotope is called the parent. What it turns into (stable isotope) is called the daughter.
12. Half – Life: - time required for half of the atoms in a sample of radioactive element to decay.
13. Half – Life Decay Graph
14. Radiometric Dating - the procedure of calculating the absolute ages of rocks and minerals that contain radioactive isotopes.
15. Dating with Carbon-14Used to date only the most recent organic materialShortest half-life.Dating with Uranium-238- Used to date rocks as old as the earth itself. ESRT pg 1
16. EXAMPLE If you can see in a leather sandal there is one quarter C14 and three quarters N14, the sample must have gone through how many half-lives?
17. EXAMPLE: You Try . .If you can see in a wooden axe handle there is 1/16th of C14 remaining, the sample must have gone through ________ half-lives and is ___________ yrs old.
18. Black History MonthHow many Black Soldiers were there in the Union Army during the American Civil War?186,000