### Dating Methods 2 Radiometric Dating --- #### Review: What is an "isotope"? <img src="/assets/slides/isotopes.png" style="margin: 0 auto; display: block;"> --- #### Review: What is the fundamental force that causes beta decay? <img src="/assets/slides/weakforce.jpg" style="margin: 0 auto; display: block; height: 70vh"> --- ### What is a half-life? - The amount of time it takes for half of the parent isotopes to decay to daughter isotopes. <img src="/assets/slides/halflife.jpg" style="margin: 0 auto; display: block; height: 60vh"> --- #### How can beta decay and half-lives tell us the age of a material? - The percentage of undecayed material and the half-life can tell us how old something is. <!-- .element: class="fragment" data-fragment-index="1" --> - If 50% of the material remains, the substance is one half-life old. <!-- .element: class="fragment" data-fragment-index="2" --> - If 25% of the material remains, the substance is two half-lives old. <!-- .element: class="fragment" data-fragment-index="3" --> - etc. <!-- .element: class="fragment" data-fragment-index="3" --> --- <iframe src="https://phet.colorado.edu/sims/cheerpj/nuclear-physics/latest/nuclear-physics.html?simulation=radioactive-dating-game" width="100%" height="800"></iframe> --- | Parent Isotopes | Daughter Isotopes | Half-Life of Parent | Effective Dating Range | Materials that can be dated | | --------------- | ----------------- | ------------------- | ---------------------- | ---------------------------------------------------------------- | | Uranium-238 | Lead-206 | 4.5 BY | 10 MY - 4.6 BY | Meteorites, Heavy materials | | Potassium-40 | Argon-40 | 1.3 BY | 50,000 Y - 4.6 BY | Whole volcanic rock | | Rubidium-87 | Strontium-87 | 47 BY | 10 MY - 4.6 BY | Whole metamorphic or igneous rock | | Carbon-14 | Nitrogen-14 | 5730 | 100 Y - 70,000 Y | Wood, charcoal, paint, bones, tissue, shells, water, glacier ice | <a href="https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fc2.staticflickr.com%2F4%2F3566%2F3588634881_a0cefbe601.jpg&f=1&nofb=1&ipt=feb4677a6873e88bca7164a6ac0eb268f6a26659b2fa4382699e177f88f42269&ipo=images"><cite>Source</cite></a> <style> table { transform: scale(0.75); margin: -140px !important; } </style>