Presentation on theme: "Science, Systems, Matter, and Energy"— Presentation transcript:
1 Science, Systems, Matter, and Energy Chapter 2Science, Systems, Matter, and EnergyMatter“High-Q” Energy“Low-Q” Energy
2 Chapter Overview Questions What is science, and what do scientists do?What are major components and behaviors of complex systems?What are the basic forms of matter, and what makes matter useful as a resource?What types of changes can matter undergo and what scientific law governs matter?
3 Chapter Overview Questions (cont’d) What are the major forms of energy, and what makes energy useful as a resource?What are two scientific laws governing changes of energy from one form to another?How are the scientific laws governing changes of matter and energy from one form to another related to resource use, environmental degradation and sustainability?
4 THE NATURE OF SCIENCE Purpose of science: What do scientists do? Discover order in the natural world and make predictions about what is likely to happen in the futureWhat do scientists do?Collect data.Form hypotheses.Develop theories, models and laws about how nature works.next
5 Stepped Art Ask a question Do experiments and collect data Interpret dataWell-tested andaccepted patternsIn data becomescientific lawsFormulate hypothesisto explain dataDo more experimentsto test hypothesisRevise hypothesisif necessaryWell-tested andacceptedhypothesesbecomescientific theoriesStepped ArtFig. 2-3, p. 30
6 Scientific Theories and Laws: The Most Important Results of Science Scientific TheoryWidely tested and accepted hypothesis.Atomic TheoryScientific LawWhat we find happening over and over again in nature.Gravitational Constant“Peer Review”next
7 by scientific community Research resultsScientific paperPeer review byexperts in fieldPaperrejectedPeer Review Process…Paper acceptedFigure 2.3Scientists use a peer review process to help identify sound science.Paper published inscientific journal…Brutal!Research evaluatedby scientific communityFig. 2-3, p. 30
8 Testing HypothesesScientists test hypotheses using controlled experiments and constructing mathematical models.Variables or factors influence natural processesSingle-variable experiments involve a control and an experimental group.Most environmental phenomena are multivariate and are hard to control in an experiment.Models are used to analyze interactions of variables.
9 A Controlled Experiment:The Effects of Deforestation on the Loss of Water and Soil Nutrients (p.28) 9
10 Scientific Reasoning and Creativity Inductive reasoningInvolves using specific observations and measurements to arrive at a general conclusion or hypothesis.Bottom-up reasoning going from specific to general.Deductive reasoningUses logic to arrive at a specific conclusion.Top-down approach that goes from general to specific.
11 Frontier Science, Sound Science, and Junk Science Reliable science a.k.a. consensus science a.k.a. sound science consists of data, theories and laws that are widely accepted by experts.Tentative science a.k.a. frontier science has not been widely tested (starting point of peer-review).Unreliable science a.k.a. junk science is presented as sound science without going through the rigors of peer-review.
12 Paradigm ShiftParadigm Shift- a complete change in worldview as a result of new informationEx Earth-centered to sun-centered view of solar system
13 Limitations of Environmental Science Inadequate data and scientific understanding can limit and make some results controversial.Scientific testing is based on disproving rather than proving a hypothesis.Based on statistical probabilities.
14 MODELS AND BEHAVIOR OF SYSTEMS Usefulness of modelsComplex systems are predicted by developing a model of its inputs, throughputs (flows), and outputs of matter, energy and information.Models are simplifications of “real-life”.Models can be used to predict if-then scenarios.Poorly defined models of a system result in unreliable results…models are continuously tested against new real data
15 Feedback Loops: How Systems Respond to Change Outputs of matter, energy, or information fed back into a system can cause the system to do more or less of what it was doing.Positive feedback loop (a.k.a.reinforcing loop) causes a system to change further in the same direction (e.g. population, fighting, erosion, greed)Negative feedback loop (a.k.a. balancing loop) causes a system to change in the opposite direction (e.g. seeking shade from sun to reduce stress, hunger & eating, body temp regulation).
16 Feedback Loops: How Systems Respond to Change Practice Positive Practice NegativeFeedback Loop Feedback Loop•brother & sister yelling • hunger & eatingDraw each loop and determine if it represents positive or negative feedback:• thirst & drinking•pine trees & seeds•body temperature (hot day) & sweating•bank account & interest payment•angry thought & angry feelings
17 Feedback Loops:Threshold Behavior- Negative feedback can take so long that a system reaches a tipping point and drastically changes.E.g. tipping over in a chair; the recent economic troubles; a smoker gets cancerProlonged delays may prevent a negative feedback loop from occurring.Synergy- Processes and feedbacks in a system can interact to amplify the results.E.g. smoking exacerbates the effect of asbestos exposure on lung cancer.
18 Feedback Loops: Some negative feedback loops have explicit goals Balancing MetersticksBody TemperatureBlood CO2 levelsEtc.
19 TYPES AND STRUCTURE OF MATTER Elements and CompoundsMatter exists in chemical forms as elements and compounds.Elements (represented on the periodic table) are the distinctive building blocks of matter.Carbon, hydrogen, oxygen, nitrogen, etcCompounds: two or more different elements held together in fixed proportions by chemical bonds.CO2, H2O, C6H12O6
21 IonsAn ion is an atom or group of atoms with one or more net positive or negative electrical charges.The number of positive or negative charges on an ion is shown as a superscript after the symbol for an atom or group of atomsHydrogen ions (H+), Hydroxide ions (OH-)Sodium ions (Na+), Chloride ions (Cl-)
22 *bases are “basic” a.k.a. “alkaline” The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution.0 = strongest acids7 = neutral14 = strongest basepH adjectives:*acids are “acidic”*bases are “basic” a.k.a. “alkaline”Figure 2-5
24 Compounds and Chemical Formulas Chemical formulas are shorthand ways to show the atoms and ions in a chemical compound.Combining Hydrogen ions (H+) and Hydroxide ions (OH-) makes the compound H2O (dihydrogen oxide, a.k.a. water).Combining Sodium ions (Na+) and Chloride ions (Cl-) makes the compound NaCl (sodium chloride a.k.a. salt).
25 Organic Compounds: Carbon Rules Organic compounds contain carbon atoms combined with one another and with various other atoms such as H+, N+, or Cl-.Organic compounds contain at least two carbon atoms combined with each other and with atoms.Methane (CH4) is the only exception.All other compounds (without C) are inorganic.
26 Organic Compounds: Carbon Rules Hydrocarbons: compounds of carbon and hydrogen atoms (e.g. methane (CH4)).Chlorinated hydrocarbons: compounds of carbon, hydrogen, and chlorine atoms (e.g. DDT (C14H9Cl5)).Simple carbohydrates: certain types of compounds of carbon, hydrogen, and oxygen (e.g. glucose (C6H12O6)).Complex carbohydrates: chains of glucose, such as starch or cellulose
27 Cells: The Fundamental Units of Life Cells are the basic structural and functional units of all forms of life.Prokaryotic cells (bacteria) lack a distinct nucleus.Eukaryotic cells (plants and animals) have a distinct nucleus.Figure 2-6
28 DNA (information storage, no nucleus) (a) Prokaryotic CellDNA (information storage, no nucleus)Figure 2.6Natural capital: (a) generalized structure of a prokaryotic cell. Note that a prokaryotic cell lacks the distinct nucleus and generalized structure of (b) a eukaryotic cell. The parts and internal structure of cells in various types of organisms such as plants and animals differ somewhat from this generalized model.Cell membrane(transport ofraw materials andfinished products)Protein constructionand energy conversionoccur without specializedinternal structuresFig. 2-6a, p. 37
29 (b) Eukaryotic Cell Nucleus (information storage) Energy conversion Figure 2.6Natural capital: (a) generalized structure of a prokaryotic cell. Note that a prokaryotic cell lacks the distinct nucleus and generalized structure of (b) a eukaryotic cell. The parts and internal structure of cells in various types of organisms such as plants and animals differ somewhat from this generalized model.ProteinconstructionCell membrane(transport of rawmaterials andfinished products)PackagingFig. 2-6b, p. 37
30 Macromolecules, DNA, Genes and Chromosomes Large, complex organic molecules (macromolecules) make up the basic molecular units found in living organisms.Complex carbohydratesProteinsNucleic acidsLipidsFigure 2-7
31 Stepped Art Fig. 2-7, p. 38 A human body contains trillions of cells, each with an identicalset of genes.There is a nucleus inside eachhuman cell (except red blood cells).Each cell nucleus has an identicalset of chromosomes, which arefound in pairs.A specific pair of chromosomescontains one chromosome fromeach parent.Each chromosome contains a longDNA molecule in the form of a coileddouble helix.Genes are segments of DNA onchromosomes that contain instructionsto make proteins—the building blocksof life.The genes in each cell are codedby sequences of nucleotides intheir DNA molecules.Stepped ArtFig. 2-7, p. 38
32 States of MatterThe atoms, ions, and molecules that make up matter are found in three physical states:solid, liquid, gaseous.A fourth state, plasma, is a high energy mixture of positively charged ions and negatively charged electrons.The sun and stars consist mostly of plasma.Scientists have made artificial plasma (used in TV screens, gas discharge lasers, florescent light).
33 Matter QualityMatter can be classified as having high or low quality depending on how useful it is to us as a resource.High quality matter is concentrated and easily extracted.low quality matter is more widely dispersed and more difficult to extract.Figure 2-8
34 Coal-fired power plant emissions High QualityLow QualitySolidGasSaltSolution of salt in waterCoalCoal-fired power plant emissionsFigure 2.8Examples of differences in matter quality. High-quality matter (left column) is fairly easy to extract and is concentrated; low-quality matter (right column) is more difficult to extract and is more widely dispersed than high-quality matter.GasolineAutomobile emissionsAluminum canAluminum oreFig. 2-8, p. 39
35 CHANGES IN MATTERMatter can change from one physical form to another or change its chemical composition.When a physical or chemical change occurs, no atoms are created or destroyed.Law of conservation of matter.Physical change maintains original chemical composition.Chemical change involves a chemical reaction which changes the arrangement of the elements or compounds involved.Chemical equations are used to represent the reaction.
36 Chemical Change Energy is given off during the reaction as a product. Mass does not change (Conservation of Matter)
37 Three Types of Atomic Nuclear Changes Radioactive decayFission- splitting atoms (like uranium)First atomic bombsAll nuclear power plantsFusion- fusing atoms together (like hydrogen)“H-Bomb”Sun and all other stars100 million degrees Celsius to begin reaction
38 Nuclear Changes: Fission Nuclear fission: nuclei of certain isotopes with large mass numbers are split apart into lighter nuclei when struck by neutrons.Figure 2-9
39 Stepped Art Fig. 2-6, p. 28 Uranium-235 Energy Fission fragment n NeutronStepped ArtFig. 2-6, p. 28
40 Nuclear Changes: Fusion Nuclear fusion: two isotopes of light elements are forced together at extremely high temperatures until they fuse to form a heavier nucleus.Figure 2-10
41 Reaction Conditions Products Fuel Proton Neutron Energy Hydrogen-2 (deuterium nucleus)+100million °C+Figure 2.10The deuterium–tritium (D–T) nuclear fusion reaction takes place at extremely high temperatures.Helium-4 nucleus++Hydrogen-3(tritium nucleus)NeutronFig. 2-10, p. 42
42 Nuclear Changes: Radioactive Decay Natural radioactive decay: unstable isotopes spontaneously emit fast moving chunks of matter (alpha or beta particles), high-energy radiation (gamma rays), or both at a fixed rate.Radiation is commonly used in energy production and medical applications.The rate of decay is expressed as a half-life (the time needed for one-half of the nuclei to decay to form a different isotope).
43 Matter: Types of Pollutants Factors that determine the severity of a pollutant’s effects: chemical nature, concentration, and persistence.Pollutants are classified based on their persistence:Degradable pollutants- can be broken downBiodegradable pollutants- e.g. human sewageSlowly degradable pollutants- e.g. most plastics; chlorinated hydrocarbons like DDTNondegradable (a.k.a. persistent) pollutants- e.g. lead, mercury, arsenic
44 ENERGY Energy is the ability to do work and transfer heat. Kinetic energy –energy in motionheat, electromagnetic radiationPotential energy –stored for possible usebatteries, glucose molecules, any food, water behind a dam
45 Electromagnetic Spectrum Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content.Next
46 Sun Ionizing radiation Nonionizing radiation Cosmic rays Gamma Rays Farultra-violetwavesNearultra-violetwavesNearinfraredwavesFarinfraredwavesCosmicraysGammaRaysX raysVisibleWavesMicro-wavesTVwavesRadioWavesFigure 2.11The electromagnetic spectrum: the range of electromagnetic waves, which differ in wavelength (distance between successive peaks or troughs) and energy content.High energy, shortWavelengthWavelength in meters(not to scale)Low energy, longWavelength
47 Electromagnetic Spectrum Organisms vary in their ability to sense different parts of the spectrum.Next
48 Energy emitted from sun (kcal/cm2/min) VisibleFigure 2.12Solar capital: the spectrum of electromagnetic radiation released by the sun consists mostly of visible light.InfraredUltravioletWavelength (micrometers)Fig. 2-12, p. 43
49 Source of Energy Energy Tasks Relative Energy Quality (usefulness) ElectricityVery high temperature heat(greater than 2,500°C)Nuclear fission (uranium)Nuclear fusion (deuterium)Concentrated sunlightHigh-velocity windVery high-temperature heat (greater than 2,500°C) for industrial processes and producing electricity to run electrical devices (lights, motors)High-temperature heat(1,000–2,500°C)Hydrogen gasNatural gasGasolineCoalFoodMechanical motion to movevehicles and other things)High-temperature heat(1,000–2,500°C) forindustrial processes andproducing electricityNormal sunlightModerate-velocity windHigh-velocity water flowConcentrated geothermal energyModerate-temperature heat(100–1,000°C)Wood and crop wastesModerate-temperature heat(100–1,000°C) forindustrial processes, cooking, producingsteam, electricity, andhot waterFigure 2.13Natural capital: categories of the qualities of different sources of energy. High-quality energy is concentrated and has great ability to perform useful work. Low-quality energy is dispersed and has little ability to do useful work. To avoid unnecessary energy waste, you should match the quality of an energy source with the quality of energy needed to perform a task.Dispersed geothermal energyLow-temperature heat(100°C or lower)Low-temperature heat(100°C or less) forspace heatingFig. 2-13, p. 44
50 ENERGY LAWS: TWO RULES WE CANNOT BREAK The first law of thermodynamics: we cannot create or destroy energy (a.k.a. Law of Conservation of Energy)We can change energy from one form to another.burning Cheeto: Chemical→ thermal & electromagneticThe second law of thermodynamics: energy quality always decreases (a.k.a. Law of Entropy)When energy changes from one form to another, it is always degraded to a more dispersed form.Energy efficiency is a measure of how much useful work is accomplished before it changes to its next form.
51 Mechanical energy (moving, thinking, living) Second Law of ThermodynamicsMechanical energy (moving, thinking, living)Chemicalenergy(photosynthesis)Chemicalenergy(food)SolarenergyWasteHeatWasteHeatWasteHeatWasteHeatFigure 2.14The second law of thermodynamics in action in living systems. Each time energy changes from one form to another, some of the initial input of high-quality energy is degraded, usually to low-quality heat that is dispersed into the environment.Fig. 2-14, p. 45
52 SUSTAINABILITY AND MATTER AND ENERGY LAWS Unsustainable High-Throughput Economies: Working in Straight LinesConverts resources to goods in a manner that promotes waste and pollution.Next
53 Throughputs Inputs Outputs SystemThroughputsInputs(from environment)Outputs(into environment)High-quality energyUnsustainablehigh-wasteeconomyLow-quality energy (heat)MatterWaste and pollutionFigure 2.15The high-throughput economies of most developed countries rely on continually increasing the rates of energy and matter flow. This practice produces valuable goods and services but also converts high-quality matter and energy resources into waste, pollution, and low-quality heat.Fig. 2-15, p. 46
54 Energy Inputs Throughputs Outputs Energy resources Heat Matter Waste andpollutionEconomyFigure 2.10Inputs, throughput, and outputs of an economic system. Such systems depend on inputs of matter and energy resources and outputs of waste and heat to the environment. Such a system can become unsustainable if the throughput of matter and energy resources exceeds the ability of the earth’s natural capital to provide the required resource inputs or the ability of the environment to assimilate or dilute the resulting heat, pollution, and environmental degradation.Goods andservicesInformationFig. 2-10, p. 44
55 Sustainable Low-Throughput Economies: Learning from Nature Matter-Recycling-and-Reuse Economies: Working in CirclesMimics nature by recycling and reusing, thus reducing pollutants and waste.It is not sustainable for growing populations.Why not?Only sustainable if population stabilizes (ZPG)!
56 Figure 2.11Positive feedback loop. Decreasing vegetation in a valley causes increasing erosion and nutrient losses, which in turn causes more vegetation to die, which allows for more erosion and nutrient losses. The system receives feedback that continues the process of deforestation.Fig. 2-11, p. 45
57 Figure 2.12Negative feedback loop. When a house being heated by a furnace gets to a certain temperature, its thermostat is set to turn off the furnace, and the house begins to cool instead of continuing to get warmer. When the house temperature drops below the set point, this information is fed back, and the furnace is turned on and runs until the desired temperature is reached. The system receives feedback that reverses the process of heating or cooling.Fig. 2-12, p. 45
58 Data AnalysisMarine scientists from the U.S. state of Maryland have produced the following two graphs as part of a report on the current health of the Chesapeake Bay. They are pleased with the recovery of the striped bass population but are concerned about the decline of the blue crab population, because blue crabs are consumed by mature striped bass. Their hypothesis is that as the population of striped bass increases, the population of blue crab decreases.p. 49
59 Data AnalysisMarine scientists from the U.S. state of Maryland have produced the following two graphs as part of a report on the current health of the Chesapeake Bay. They are pleased with the recovery of the striped bass population but are concerned about the decline of the blue crab population, because blue crabs are consumed by mature striped bass. Their hypothesis is that as the population of striped bass increases, the population of blue crab decreases.p. 49