ENVS 210 1st Edition Lecture 3 Outline of Last Lecture II. Easter IslandIII. Differences between the 4th and 5th book editionsa. Paradigm changeIV. Tragedy of the commonsOutline of Current Lecture V. Nuclear energya. Nuclear fissionVI. Isotopes and ionsa. Defining isotopesb. Defining mass numberVII. Radioactive isotopesa. Half lifeVIII. Radioactive elements released from FukushimaIX. Geologya. Earth’s layersb. Continental drift (Alfred Wagner and Pangaea)c. How plates moved. Plate interactions (convergent, divergent transform boundaries)e. Rock cycle (igneous, sedimentary, metamorphic rocks)f. Geologic hazards (earthquakes, volcanoes, tsunamis)Current Lecture- Nuclear energyo Energy that holds protons and neutrons together within the nucleus (“weak force”)o Nuclear fission= splitting apart of the U-235 nuclei with slow neutrons Produces fragments, neutrons and energy Energy is used to heat water to steam Steam is used to generate electricity using a turbineo 20% of energy in US comes from nuclear energy- Isotopes and ionso Isotopes= atoms of the same element with different numbers of neutrons Isotopes of an element behave differentlyo Mass number= the combined number of protons and neutronsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Atoms that gain or lose electrons become electrically charged ions- Some isotopes are radioactiveo Radioactive isotopes decay until they become non-radioactive stable isotopes Emit high-energy radiation (alpha particles, beta particles, and gamma rays)o Half-life= the amount of time it takes for one-half of the atoms to give off radiation and decay Different radioisotopes have different half-lives ranging from fractions of a second to billions of years U-235 used in nuclear power. Half life of 700 million years- Radioactive elements released from Fukushima in the oceano Salts like Cs + dissolve well, so good indicator of ocean transporto Track Cs 137 and Cs 134o Cs 134= half life of 2 yearso Cs 137= half-life of 30 years.Geology- Geologyo Study of the earth’s physical features, processes and historyo Earth is 4.5 billion years old- Earths layerso Core= inner and outero Mantle= upper and lowero Crust= continental (25mi) and oceanic (5 mi)o Most geologic action takes place near surface (uppermost portion of mantle and core)- Continental drifto Alfred Wegener= continental drift (movement of continents)o Pangaea- Pangaeao Forced 300million years agoo Broke up 100 million years agoo Supported by fossils and plants, geologic layers, and glacial depositso 15 major plants (move 1-6 inches a year)- how plates moveo Convective currents through mantle Hot rock rises, cool rock sinkso Large plates of crust ride along mantles as it moveso New crust created @ ridges- Plate interactiono Divergent= plates move aparto Convergent= plates come together (subduction zones)o Transform= plates slide past each other (faults)- The rock cycleo Igneous= magma (granite)o Sedimentary= formed by layers of sediment (created by weather and erosion, sandstone)o Metamorphic= formed when existing rocks are put under high heat and pressures (marble and slate)- Geologic hazardso Volcanoes= occur along plate boundaries (ring of fire), hotspots, crustal stretching- Earthquakeso Occur along a fault plane= planar surface where displacement of rock ahs occurredo Can be caused by tectonic movement, volcanism, or human activity- Tsunamio Caused by underwater volcanoes, glacier calving, meteorite impacts, landslides, bombs and earthquakeso Earthquakes cause a sudden upward displacement of water due to tectonic rebound at a subduction