kEnergy: Basic ConceptsPotential energy+ kinetic energy decreases with each bounce, and ball heats up; eventually stops as a ‘hot ball’ that loses that heat to the surroundingsGreek derivation: ‘work within’Ability to do work= energyWork= force acting though a distance (ball had potential energy, which then became kinetic energy. gravity acted on the ball)Heat= energy changes affecting molecular motion and temperature changesEx: explosion: energy evolved as HEAT and WORKWork- air is suddenly expanding, air molecules are doing work and fastHeat and Work are mans to exchange energy with surroundingsEnergy is flowing through ecosystems (unlike nutrients which cycle)First Law of ThermodynamicsEnergy is not created or destroyed; it is conservedTransformed between forms in ordinary processesAmong different forms of energy>MechanicalElectricalLightChemicalHeatSecond Law of Thermodynamicsrelates to direction of spontaneous changespontaneous changes increase entropy of the universerelates to how mch energy is dispersed and how widely it is ‘spread out’also related to ‘disorder’ or ‘randomness’loss of heat and increasing disorder are natural, essential processesenergy needs to be put in to create orderpeople need to eat in order to maintain orderInplications of Second Law for LifeSpontaneous energy change not 100% efficientWaste heat usually produced; energy dispersed‘life’ is ‘unnatural’ in high state of internal order (low entropy)done via ‘pumping out disorder,’ ‘spreading energy out’put in high utility energy; food or lightwithout enery transfers ; no life of ecosystems possiblehuman life and civilizations; remarkable, natural systems dependent on continuous flow of energy (sunlight to heat)agricultural/ industrial revolutions: changed energy from mostly muscles/ fires- changed to fossil fuels- coal natural gasQuantify energy flow:ratio of respiration – to –biomass: R/B (rhythm and blues ;))atp becomes cellular currencysimilar to mpg for a carrelated to ‘maintenance – to – structure” of systemeating multiple times a dayR/B approximations per day (Chart)What he is saying“one coke wouldn’t be enough calories”“plants- related to photosynthesis and respiration”phytoplanktonhumanswe are more efficient than these other organismsone of the reasons we are successful on earththere are times when we don’t eatGPP via photosynthesis- another measure of energy flowMarine ecosystem chartWhat he is saying“ come in toward coast- energy intensity doubles because of nutrient input, sediment input, human impactupwelling zone- nutrient rich water flow up to surface, high intensityestuaries and reefsBAY- important place in terms of energy flow per sq meterWe want to preserve them not because of energy flowsTROPHIC STRUCTURE: ILLUSTRATES THAT ENERGY IS FLOWING THROUGH THE SYSTEMHuman Energy Use systems: Depletable vs. RenewableDepletable: use > replenishmentCoal, oil, natural gasRenewable: repleacable or not depletableWater power and plant biomass (replaceable – part of hydrologic and c cyclesWater has potential energy, is changed to kinetic energy and then electric currentSolar and wind power (not depleteable – flow through; not tapping cycles)Pre-industrial revolution (< 1760s in northern England) ; renewables usedMuscles, biomass, solar windHuman NRG Use SystemsConventional since 18th centuryDepletableCoal , oil, natural gas, nuclearSituation today: Human Uses~89% of US energy use from fossil fuels~80% of world energy from fuelsPeak OilEtc etc etc blah blah blahA Nuclear Power Plant is a BoilerUranium fuel has to be minedOctober 10, 2011Second law of ThermodynamicsEntropy increasesFirst lawEnergy transformedNuclear PowerLocated near water?They need water to cool excess heats, water absorbs heat…cooling towers so that water doesn’t overheat riverThere is no combustion or carbon being burned- no CO2/other ghgNuclear Power AttributesNo carbon dioxide/other ghgNo air or water pollution (some heat)Wastes and plant> radioactive (1000s of years; no definitely safe solutions…Yucca mtn, NV)Potential for accidents a concernProduction of bomb-grade, fissionable material > nuclear weapons?Current issues with n. korea and iranVolume of waste per year from a big plant would fit under ur dining room tableUranium ore supplies widely dispersed in the world, but might only last a few decades, especially if nuclear energy expandsReprocessing wastes recovers unspent U and newly produced Pu: many questions ariseAlternative Human Energy SystemsSEEE CHAPTER 20 IN C&CReplacealeHydropowerBiomassNon-depleteableWindGeothermalTidal and waveSolarHydrogen and fuel CellsFirst a counterpoint on wood energyFuelwood Crisis dimensionsPrimary energy for >2 billion people;[Mostly in developing nationsPrincipally women and children 10-300 days a year collecting woodUrban ‘woodsheds’- like ‘watersheds’, urban people require firewood and landscape is being cute, water quality is changing1700 million tons harvested; 500 million shortageConsequences of Fuelwood CrisisDeforestationHabitat lossSoil erosionCarbon dioxide releaseUse of animal maure for fuelDecrease in soil organic matterDecrease in soil fertilityGender issues and family disruptionIndoor air pollutionScience and Policy ResponsesReforestationCommunity woodlotsEfficient, cleaner –burning stovesAgroforestry:Interplanting food crops with treesMay enhance soil fertility if trees are legumesErosion controlFuelwood- cheaptest available fuel/unit of heatTree Legumes50% of fuelwood treesrapid growthcan coppice (repeatedly cut down)high calorific valueburns without toxic smoke or sparks-cleanerTree Legumes: Fix N2Long-lived and low maintenanceForage for livestock (most ntritients in seeds) (Leaves and pods grazed by animals)Erosion controlSource of N for soilRevegetate saline and arid sitesFruit and vegetable production for humansOCTOBER 13, 2011Why is a nuclear power plant like a tea kettle?It uses uranimun to boil water, electricity is being createdDC to AC, generating heat but not from combustion of carbonHYDROGEN as a fuel30% of mass of sun; source of sun’s energylightest element: H = H+ + e-most easily ‘burned’ (oxidized= loses its e-)convertedx to water when oxidized by oxygen: h2 + ½ O2 > H20has to be produced; H is naturally combined with other elements (eg CH4, H20)Ways to produce H2from natural gasproduces c02 in processnatual gas will run out eventuallyelectrolysis of watersplits water to