https://padlet.com/304493/1yrmyc5op6gq 1/26/18 en-us 2018-01-26 18:44:29 UTC 2018-01-30 19:49:50 UTC hello@padlet.com 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225188249 The geologic time scale is a system of chronological dating that relates geological strata to time.]]> 2018-01-26 18:46:34 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225188249 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225188336 In geology and related fields, a stratum is a layer of sedimentary rock or soil, or igneous rock that were formed at the earth's surface, with internally consistent characteristics that distinguish it from other layers.]]> 2018-01-26 18:46:47 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225188336 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225188965 The rock cycle is an idealized cycle of processes undergone by rocks in the earth's crust. ]]> 2018-01-26 18:48:00 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225188965 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225189712 Fossils are the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.]]> 2018-01-26 18:49:45 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225189712 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225190543 The history of Earth concerns the development of Planet Earth from its formation to the present day. Nearly all branches of natural science have contributed to the understanding of the main events of Earth's past.]]> 2018-01-26 18:51:49 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225190543 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225827860 Half life is the time taken for the radioactivity of a specified isotope to fall to half its original value.]]> 2018-01-29 19:43:21 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225827860 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225827913 Radiometric dating is a method of dating geological or archeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample.]]> 2018-01-29 19:43:28 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225827913 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225828305 Radiocarbon dating is the determination of the age or date of organic matter from the relative proportions of the carbon isotopes carbon-12 and carbon-14 that it contains.]]> 2018-01-29 19:44:03 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225828305 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225829115 Radioactive decay is the spontaneous transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles.]]> 2018-01-29 19:45:24 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225829115 304493 https://padlet.com/304493/1yrmyc5op6gq/wish/225829177 This age may represent the age of the Earth's accretion, of core formation, or of the material from which the Earth formed.]]> 2018-01-29 19:45:31 UTC https://padlet.com/304493/1yrmyc5op6gq/wish/225829177