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Earth’s Physical Systems: Matter, Energy and Geology. Anna Kajzer www.science.kennesaw.edu/~jhendrix What is matter? All material in the universe that has mass and occupies space The amount of matter stays constant as it is recycled (law of conservation of matter), it can’t be created or destroyed It is composed of organic and inorganic compounds Is the law of conservation of matter important in the environment? Yes, pollution and waste will not simply disappear when we dispose them! Plastics (synthetic polymers), such as polyethylene, polypropylene, polyurethane, and polystyrene are manufactured products that are long – lasting and resist chemical breakdown, BUT they are serious source of waste and pollution, which endangers wildlife and human health for a long time. What are polymers? Chemical compounds or mixture of compounds consisting of long chains of repeated molecules Some polymers play key roles in the building blocks of life What are the building blocks of life? Some polymers, such as proteins, nucleic acids, carbohydrates (starch, chitin, cellulose), lipids, fats, oils, and waxes. They are organic compounds having carbon atom/s and other elements. Scientists use the concept of the building blocks (macromolecules) to produce synthetic polymers. Are only synthetic polymers cause concern in the environment? No!!! Nucleic acids present in DNA and RNA (organic macromolecules) that carry hereditary information for organisms. Regions of DNA called genes that code for specific functions get manipulated in the gene engineering to produce mutant organisms (genetic engineering). Consequences are unknown, eg. Cultivated plants may become weeds (unwanted plants), Which of the organic compounds are important in the environment? Hydrocarbons containing carbon and hydrogen Some hydrocarbons, such as the polycyclic aromatic hydrocarbons, PAHs, are found in gasoline and oil as well as in combustion products and are known to be toxic to wildlife and humans. What are the other compounds that cause concern? (compounds are made of two or more different elements) Carbon dioxide consisting of one carbon atom and two oxygen atoms CO2 - a colorless gas used by plants for photosynthesis, given off by respiration, and released by burning fossil fuels. A primary greenhouse gas whose buildup contributes to global climate change (greenhouse effect) Is ozone a compound? No, O3 (ozone) is a molecule. A molecule is formed when atoms bond together, such as oxygen or ozone Ozone absorbs UV radiation in the stratosphere. What is ozone hole? It is thinning of the stratospheric ozone layer ( 10-19 mi above sea level) that occurs over Antarctica each year, as a result of chlorofluorocarbons (halocarbons) Halocarbons are human made chemical compounds derived from simple hydrocarbons in which hydrogen atoms are replaced by halogen atoms such as bromine, fluorine, or chlorine. What are atoms? The smallest units maintaining chemical properties of the element. Atom has a nucleus in which there are positively charged protons (atomic number) and neutrons having no charge (sum is called the mass number) and electrons negatively charged particles surrounding a nucleus. The number of protons, neutrons, and electrons is usually the same. Na (sodium has 11 protons,11 neutrons and 11 electrons) If the number of protons and neutrons is different do the atoms behave the same? No, they have the same chemical properties, but different physical properties. They are called ISOTOPES. Some isotopes may be radioactive, such as Uranium 235, our source for nuclear power. Radioactive isotopes change their chemical identity as they shed atomic particles and emit high energy radiation, it “decays” till it becomes a stable isotope. For Uranium half-life (the amount of time it takes for half of the radioactive isotope to decay) is 700 million years (danger of explosion of nuclear power, eg, Tsunami in Japan and explosion of nuclear reactors) How do elements, molecules and compounds come together? With chemical bonding or Without chemical bonding. What is chemical bonding? Attraction for electrons Electrons may be shared eg H – H molecular bonding O=O (non-metals) H \ O hydrogen bonding in water H / Electrons may be transferred (metal + non-metal) Na – e = Na + (ion) Cl + e = Cl - (ion) Sodium donated one electron to chlorine This is called ionic bonding forming salts NaCl is an ionic compound How do elements molecules and compounds come together without chemical bonding? They mix together and form mixtures Mixtures can be heterogenous (muddy water) or homogenous = solutions (salty water) What are the properties of water? Universal solvent Is cohesive Has high heat absorption capacity It may occur in one of the three phases: gas, liquid or solid A solid form is less dense than the liquid form It has an ability to dissolve or hold in solution many other molecules What is acidity? Hydrogen ions determine acidity Solutions in which H+ concentration are greater than OH- are acidic. The reverse case is basic or alkaline. The pH (potency of hydrogen) scale quantifies acidity or alkalinity. pH less than 7 indicates acidity (lime juice), pH greater than 7 indicates alkalinity (soap), pH 7 is neutral (pure water) What is acid rain? Acid deposition (settling of acidic or acid forming pollutants from the atmosphere onto Earth’s surface. Presence of hydrogen ions determines acidity of this aqueous solution (acid rain) What is energy? It is capacity to change the position, physical composition or temperature of matter. It is force that can accomplish work Energy is always conserved but it may change form to another (when water surges to the surface, the kinetic energy of its movement will equal the potential energy it held underground)= First Law of Thermodynamics Energy tends to change from more-ordered state to a less – ordered state. Second Law of Thermodynamics. Systems tend to move toward increasing disorder (entropy). The order of an object or system can be increased through the input of additional energy from outside the system. In every transfer of energy, some portion escapes. The degree to which we successfully capture energy is called Energy Conversion Efficiency (ratio of useful output of energy to the amount that needs to be input). Where does energy come from? (in living organisms) There are different sources of energy. Light energy from the sun is used by the plants (autotrophs = primary producers) in the process of photosynthesis to produce food. NB. Pollution, volcanic ashes inhibit passage of radiation. Chemical energy from hydrogen sulfide is used by deep ocean organisms to produce their own food (chemosynthesis). How is photosynthesis and respiration related? They are complementary processes. Animals (heterotrophs = consumers) depend on the sugars and oxygen from photosynthesis. In cellular respiration chemical energy is released (cells employ oxygen to convert glucose back into its original starting material i.e., carbon dioxide and water, and energy is released. Why is chemical energy important? Chemical energy is a special type of potential energy that may be changed into kinetic energy = energy of motion (walking, exercising, doing work). Does Earth have or need energy? (non-living things). Yes, ocean tides are caused by the gravitational pull (energy) of the moon in conjunction with the sun) Geothermal heating emanating from the inside the earth is powered by radiation from the radioisotopes deep inside our Earth. What is geology? The study of Earth’s physical features, processes and history. What are the physical features of Earth? Structure, Earth consists of layers 1. A dense core at the center consisting of iron, solid in the inner core and molten in the outer core. 2. Mantle, (less dense than the core) elastic layer, having a layer called asthenosphere, soft rock and a layer called lithosphere including 3. Crust = the thin layer of rock that covers the surface of Earth. Does Earth have constant temperature? No, the heat from inner Earth rises to the surface and dissipates. Within a few miles of the surface (asthenosphere) we can drill ot tap geothermal energy. The soil and rock just below the surface has fairly constant temperature (cooler than the air in summer and warmer than the air in winter); it allows to use geothermal energy for heating of the houses in more efficient way. Does the heat from the inner of Earth have any influence on the crust? Yes, it drives convection currents that move mantle material. This material moves and drags lithospheric plates along the surface = plate tectonics. Does plate tectonics shape Earth’s geography? Yes, Earth consists of about 15 major tectonic plates which move about 2 to 15 cm per year. This movement influences Earth’s climate and life’s evolution. How many types of plates boundaries are there? Three 1. New crust may be created (at divergent plate boundaries, tectonic plates push apart as magma rises upward to the surface, creating new crust, eg. Mid-Atlantic ridge) 2. Where two plates meet, they may slip and grind alongside one another, forming a transform plate boundary = a fault eg. San Andreas Fault in California. Plates may collide at convergent plate boundaries and 1. Subduction may occur (one plate slide beneath the other) causing volcanic eruptions eg. The Cascades in the Pacific Northwest led to the eruption of Mt. Saint Helens in 1980 and 2004 2. Continental collision where the continental plates meet and both sides resist subduction, they crush together, bending and deforming layers of rock, eg. The Himalayas were formed in this manner. What do tectonics do on Earth? Produce Earth’s landforms, eg. The Geysers in California located above a region of subduction (magma rises to the surface. Shape climate and life’s evolution b/c changes areas of coastal regions to continental and vice versa. What is rock cycle? It is one of the geological processes (the other one is plate tectonics). Rocks are heated, melted, cooled, broken down and reassembled in a very slow process over geological time. Rock is a solid aggregation of minerals (solid element of inorganic compound with a crystal structure, a specific chemical composition and distinct physical properties). What are the types of rocks? Igneous - formed when lava (magma on the surface of Earth) cools across Earth’s surface 1. Intrusive - when magma cools slowly and solidifies below Earth’s surface (large crystals such as granite) 2. Extrusive – when molten rock is ejected from a volcano and cools quickly (eg. Basalt). Sedimentary rock – when sediments are physically pressed together; dissolved minerals bind the particles together in a process called lithification, eg. Sandstone, shale and limestone. 1. Sediments (particles of rock blown by wind or washed away by water in physical processes or precipitation of substances our of solution form chemically). 2. These processes create the fossil fuels and fossils of organisms. Metamorphic rock – any type of rock is subjected to great heat or pressure, eg. slate and marble. What are the geologic and natural hazards? 1. Earthquakes and volcanoes (Earth’s geothermal heating gives rise to creative forces that shape our planet). Nine out of ten of the world’s earthquakes and over half of the world’s volcanoes occur on plate boundaries on the circum-Pacific belt, called “ring of fire”. What causes earthquakes? Movement at plate boundaries and faults. Plate boundaries and places where faults occur may relieve built-up pressure and release of energy called earthquakes. Damage from earthquakes is generally greatest where soils are loose or saturated with water. Engineers developed ways to protect buildings and there are new building codes n earthquake-prone areas such as California and Japan. What is the origin of volcanoes? They arise from rifts, subduction zones or hotspots. Where molten rock, hot gas, or ash erupt through Earth’s surface, a volcano is formed, often creating a mountain, eg. Mt Kilauea in Hawaii (lava flows continuously downhill) or Mt. Saint Helen (sudden eruption in 1980). What type of environmental impact can volcanoes cause? Depress temperature throughout the world as a result of ash blocking sunlight Sulfuric acid hazes that block radiation and cool the atmosphere. What is mass wasting? Downslope movement of soil and rock due to gravity when a landslide occur. It can be brought about by human land practices that expose or loosen soil. May occur following volcanic eruptions or torrential hurricane rainfall. Can be colossal and deadly. What are tsunamis? An immense swell or wave of water that can travel thousands of miles across oceans. They may be caused by earthquakes, volcanic eruptions, and large coastal landslides. Residents of the USA are vulnerable to tsunamis. A Canary Island volcano could put Atlantic –coast cities at risk. What are the natural hazards? Flooding Coastal erosion Wildfire Tornadoes Hurricanes Could we mitigate the impacts of natural hazards/ We can reduce the impacts of hazards through the thoughtful use of technology and a solid understanding of geology and ecology. Could we worsen the impacts of natural hazards? 1. 2. 3. 4. 5. Yes More people live in areas susceptible to disaster b/c of the population growth or b/c of our choices. We use and engineer landscapes in wasy that can increase the landslide, flooding, erosion. We change Earth’s climate by emitting greenhouse gases. We alter patterns of precipitation, increasing risks of drought, flooding and fire. Rising sea levels increase coastal erosion. CONCLUSION Comprehending matter (chemistry) and energy (physics) is essential for environmental science to find solutions. geology and its physical processes are important because they shape Earth’s surface and generate phenomena that can threaten our lives and property. Geothermal heating provides one way into the broad phenomena of chemical and physical processes that shape Earth. For further research http://response.restoration.noaa,gov/bat.about.html http://antoine.frostburg.edu/chem/sense/101/index.shtml http://nssdc.gsfc.nasa.gov/planetary.marslife.html www.pmel.noaa.gov/vents http://www.eoearth.org/ http://earthquake.usgs.gov/earthquakes/recenteqsww/ http://shopping.dicovry.com http://gallery.usgs.gov/video_collections/Natural_Hazards http://earthobservatory.nasa.gov/NaturalHazards,category.php?ca t_id=9 http://map.ngdc.noaa.gov/website/seg/hazards/viewer.htm