Absolute Dating

Vocabulary Match the vocabulary word with the correct definition. Parent Isotope The starting isotope that decays into the final product Daughter Isotope The isotope that results from radioactive decay Half-Life The time it takes half of the parent isotope to decay into the daughter isotope Absolute Dating Another term for when radiometric dating is used to find the actual age of a rock or fossil Relative Dating When the age of a rock or fossil is found compared to other rocks and fossils Parent and Daughter Isotope Match the Parent Isotope with the corresponding Daughter Isotope. Carbon 14 Nitrogen 14 Uranium 238 Lead 206 Potassium 40 Argon 40 or Calcium 40 Half-Life Table Complete the Carbon -14 Half-Life Table below with the correct percentage and age of the sample (Do NOT use the % symbol or , symbol. Just type the correct number.) Number of Half-Lives Percent of the Carbon- 14 (Parent) Isotope (%) Age of Fossil or Rock (years) 0 100 % 0 years 1 50 % 5,700 years 2 25 % 11,400 years 3 12.5% 17, 100 years 4 6.25 22, 800 years Relative or Absolute Dating Sort the words as either relative or absolute dating. Relative Dating Principle of Superposition Unconformity Absolute Dating Half-Life Exact Date Carbon Dating Fill -in the blanks using the word bank provided. Fill-in the blank using the word bank. The age of rock, fossil or material can be estimated using radioactive elements. Radioactive dating compares the amount of radioactive element to the stable element (decay product) found in the same. Most elements exists in more than one form called isotopes. Isotopes of an element have the same number of protons but different number of neutrons and therefore a different atomic mass. Some isotopes are unstable. The unstable, radioactive isotope "disintegrates" (changes) into a stable element. A radioactive element's half - life is the time it takes for one-half of the radioactive element to "decay"(change) to a stable element. Half-life is a constant value, nothing will change its value. Half-lives range from billions of years to seconds. Radioactive elements with short half-lives, such as C-14, are used for dating recent organic materials and rocks that are less than 50,000 years old from the Cenozoic era. Those with long half lives such as K-40 and U-238 are useful for dating older rocks. Radioactive carbon-14 dating has determined that a fossil is 5.7 x 103years old. What is the total amount of C14 still present in the fossil? 0% 25% 50% 75% A sample of wood is found in an ancient tomb contains 25% of its original carbon-14. The age of the this wood sample is approximately 2,800 years 5,700 years 11,400 years 17,100 years How much of an 800-gram sample of potassium-40 will remain after 3.9 x 109 years of radioactive decay? 50 grams 100 grams 200 grams 400 grams The absolute age of a rock is the approximate number of years that the rock forms. The absolute age of an igneous rock can best be determined by comparing the amounts of decayed and undecayed radioactive isotopes in the rock. comparing the sizes of the crystals found in the upper and lower parts of the rock examining the rock's relative position in a rock outcrop examining the environment in which the rock is found An archaeologist found an ancient skeleton estimated to be 10,000 to 25,000 years old. Which radioactive isotope would be most useful for finding the age of the skeleton? carbon - 14 potassium - 40 uranium - 238 rubidium - 87