Radiometric dating
{"Image DocumentName": "Absolute Dating Potassium-Argon Dating", "Image ImageDescription": "Dating of a rock sample (assuming there is a fossil in/near the rock of the same age) Decay of K \uf0e0 Ca + Ar. Isotopes of Potassium are K-39, k-40, K-41. (diff number of neutrons, same protons) K-40 is radioactive and decays into Ar-40 + Ca-40. Decay is slow but constant. Comparing K-40 to Ar-40 can provide an age for a rock. Used to date rocks 100,000 years and above. Dates before 100,000 produce to little Ar-40 (0.0053%) Half life: time taken for any given quantity of a radioactive substance to half. K \uf0e0 Ar Half life = 1.25 x 109 years. (1,250,000,000)", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}