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Chapter 2 Science, Systems, Matter, and Energy Slide 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? Slide 3 Chapter Overview Questions (contd) 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? Slide 4 Updates Online The latest references for topics covered in this section can be found at the book companion website. Log in to the books e-resources page at www.thomsonedu.com to access InfoTrac articles. InfoTrac: Underwater Microscope Finds Biological Treasures in Subtropical Ocean. Ascribe Higher Education News Service, June 26, 2006. InfoTrac: In Bacterial Diversity, Amazon Is a 'Desert'; Desert Is an 'Amazon'. Ascribe Higher Education News Service, Jan 9, 2006. InfoTrac: Making MGP wastes beneficial. Bob Paulson. Pollution Engineering, June 2006 v38 i6 p20(5). NASA: Nitrogen Cycle Environmental Literacy Council: Phosphorous Cycle National Sustainable Agriculture Information Service: Nutrient Cycles Slide 5 Video: The Throw Away Society This video clip is available in CNN Today Videos for Environmental Science, 2004, Volume VII. Instructors, contact your local sales representative to order this volume, while supplies last. Slide 6 Core Case Study: Environmental Lesson from Easter Island Thriving society 15,000 people by 1400. 15,000 people by 1400. Used resources faster than could be renewed By 1600 only a few trees remained. By 1600 only a few trees remained. Civilization collapsed By 1722 only several hundred people left. By 1722 only several hundred people left. Figure 2-1 Slide 7 Video: Easter Island From ABC News, Environmental Science in the Headlines, 2005 DVD. PLAY VIDEO Slide 8 THE NATURE OF SCIENCE What do scientists do? Collect data. Collect data. Form hypotheses. Form hypotheses. Develop theories, models and laws about how nature works. Develop theories, models and laws about how nature works. Figure 2-2 Slide 9 Fig. 2-2, p. 29 Well-tested and accepted patterns in data become scientific laws Interpret data Ask a question Do experiments and collect data Formulate hypothesis to explain data Do more experiments to test hypothesis Revise hypothesis if necessary Well-tested and accepted hypotheses become scientific theories Slide 10 Ask a question Do experiments and collect data Formulate hypothesis to explain data Do more experiments to test hypothesis Revise hypothesis if necessary Well-tested and accepted hypotheses become scientific theories Interpret data Well-tested and accepted patterns In data become scientific laws Fig. 2-3, p. 30 Stepped Art Slide 11 Scientific Theories and Laws: The Most Important Results of Science Scientific Theory Widely tested and accepted hypothesis. Widely tested and accepted hypothesis. Scientific Law What we find happening over and over again in nature. What we find happening over and over again in nature. Figure 2-3 Slide 12 Fig. 2-3, p. 30 Research results Scientific paper Peer review by experts in field Paper rejected Paper accepted Paper published in scientific journal Research evaluated by scientific community Slide 13 Testing Hypotheses Scientists test hypotheses using controlled experiments and constructing mathematical models. Variables or factors influence natural processes Variables or factors influence natural processes Single-variable experiments involve a control and an experimental group. Single-variable experiments involve a control and an experimental group. Most environmental phenomena are multivariable and are hard to control in an experiment. Most environmental phenomena are multivariable and are hard to control in an experiment. Models are used to analyze interactions of variables.Models are used to analyze interactions of variables. Slide 14 Scientific Reasoning and Creativity Inductive reasoning Involves using specific observations and measurements to arrive at a general conclusion or hypothesis. Involves using specific observations and measurements to arrive at a general conclusion or hypothesis. Bottom-up reasoning going from specific to general. Bottom-up reasoning going from specific to general. Deductive reasoning Uses logic to arrive at a specific conclusion. Uses logic to arrive at a specific conclusion. Top-down approach that goes from general to specific. Top-down approach that goes from general to specific. Slide 15 Frontier Science, Sound Science, and Junk Science Frontier science has not been widely tested (starting point of peer-review). Sound science consists of data, theories and laws that are widely accepted by experts. Junk science is presented as sound science without going through the rigors of peer- review. Slide 16 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. Scientific testing is based on disproving rather than proving a hypothesis. Based on statistical probabilities.Based on statistical probabilities. Slide 17 MODELS AND BEHAVIOR OF SYSTEMS Usefulness of models Complex systems are predicted by developing a model of its inputs, throughputs (flows), and outputs of matter, energy and information. Complex 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 are simplifications of real-life. Models can be used to predict if-then scenarios. Models can be used to predict if-then scenarios. Slide 18 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 causes a system to change further in the same direction (e.g. erosion) Positive feedback loop causes a system to change further in the same direction (e.g. erosion) Negative (corrective) feedback loop causes a system to change in the opposite direction (e.g. seeking shade from sun to reduce stress). Negative (corrective) feedback loop causes a system to change in the opposite direction (e.g. seeking shade from sun to reduce stress). Slide 19 Animation: Feedback Control of Temperature PLAY ANIMATION Slide 20 Feedback Loops: Negative feedback can take so long that a system reaches a threshold and changes. Prolonged delays may prevent a negative feedback loop from occurring. Prolonged delays may prevent a negative feedback loop from occurring. Processes and feedbacks in a system can (synergistically) interact to amplify the results. E.g. smoking exacerbates the effect of asbestos exposure on lung cancer. E.g. smoking exacerbates the effect of asbestos exposure on lung cancer. Slide 21 TYPES AND STRUCTURE OF MATTER Elements and Compounds Matter exists in chemical forms as elements and compounds. Matter exists in chemical forms as elements and compounds. Elements (represented on the periodic table) are the distinctive building blocks of matter.Elements (represented on the periodic table) are the distinctive building blocks of matter. Compounds: two or more different elements held together in fixed proportions by chemical bonds.Compounds: two or more different elements held together in fixed proportions by chemical bonds. Slide 22 Atoms Figure 2-4 Slide 23 Animation: Subatomic Particles PLAY ANIMATION Slide 24 Animation: Atomic Number, Mass Number PLAY ANIMATION Slide 25 Ions An 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 atoms Hydrogen ions (H + ), Hydroxide ions (OH - ) Hydrogen ions (H + ), Hydroxide ions (OH - ) Sodium ions (Na + ), Chloride ions (Cl - ) Sodium ions (Na + ), Chloride ions (Cl - ) Slide 26 Animation: Ionic Bonds PLAY ANIMATION Slide 27 The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution. Figure 2-5 Slide 28 Animation: pH Scale PLAY ANIMATION Slide 29 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 H 2 O (dihydrogen oxide, a.k.a. water). Combining Hydrogen ions (H + ) and Hydroxide ions (OH - ) makes the compound H 2 O (dihydrogen oxide, a.k.a. water). Combining Sodium ions (Na + ) and Chloride ions (Cl - ) makes the compound NaCl (sodium chloride a.k.a. salt). Combining Sodium ions (Na + ) and Chloride ions (Cl - ) makes the compound NaCl (sodium chloride a.k.a. salt). Slide 30 Organic Compounds: Carbon Rules Organic compounds contain carbon atoms combined with one another and with various other atoms such as H +, N +, or Cl -. Contain at least two carbon atoms combined with each other and with atoms. Methane (CH 4 ) is the only exception. Methane (CH 4 ) is the only exception. All other compounds are inorganic. All other compounds are inorganic. Slide 31 Animation: Carbon Bonds PLAY ANIMATION Slide 32 Organic Compounds: Carbon Rules Hydrocarbons: compounds of carbon and hydrogen atoms (e.g. methane (CH 4 )). Chlorinated hydrocarbons: compounds of carbon, hydrogen, and chlorine atoms (e.g. DDT (C 14 H 9 C l5 )). Simple carbohydrates: certain types of compounds of carbon, hydrogen, and oxygen (e.g. glucose (C 6 H 12 O 6 )). Slide 33 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. Prokaryotic cells (bacteria) lack a distinct nucleus. Eukaryotic cells (plants and animals) have a distinct nucleus. Eukaryotic cells (plants and animals) have a distinct nucleus. Figure 2-6 Slide 34 Fig. 2-6a, p. 37 (a) Prokaryotic Cell Protein construction and energy conversion occur without specialized internal structures Cell membrane (transport of raw materials and finished products) DNA (information storage, no nucleus) Slide 35 Fig. 2-6b, p. 37 Protein construction (b) Eukaryotic Cell Cell membrane (transport of raw materials and finished products) Packaging Energy conversion Nucleus (information storage) Slide 36 Animation: Prokaryotic and Eukaryotic Cells PLAY ANIMATION Slide 37 Macromolecules, DNA, Genes and Chromosomes Large, complex organic molecules (macromolecules) make up the basic molecular units found in living organisms. Complex carbohydrates Complex carbohydrates Proteins Proteins Nucleic acids Nucleic acids Lipids Lipids Figure 2-7 Slide 38 Fig. 2-7, p. 38 The genes in each cell are coded by sequences of nucleotides in their DNA molecules. A human body contains trillions of cells, each with an identical set of genes. There is a nucleus inside each human cell (except red blood cells). Each cell nucleus has an identical set of chromosomes, which are found in pairs. A specific pair of chromosomes contains one chromosome from each parent. Each chromosome contains a long DNA molecule in the form of a coiled double helix. Genes are segments of DNA on chromosomes that contain instructions to make proteinsthe building blocks of life. Slide 39 Fig. 2-7, p. 38 A human body contains trillions of cells, each with an identical set of genes. There is a nucleus inside each human cell (except red blood cells). Each cell nucleus has an identical set of chromosomes, which are found in pairs. A specific pair of chromosomes contains one chromosome from each parent. Each chromosome contains a long DNA molecule in the form of a coiled double helix. Genes are segments of DNA on chromosomes that contain instructions to make proteinsthe building blocks of life. The genes in each cell are coded by sequences of nucleotides in their DNA molecules. Stepped Art Slide 40 States of Matter The atoms, ions, and molecules that make up matter are found in three physical states: solid, liquid, gaseous. 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. The sun and stars consist mostly of plasma. Scientists have made artificial plasma (used in TV screens, gas discharge lasers, florescent light). Scientists have made artificial plasma (used in TV screens, gas discharge lasers, florescent light). Slide 41 Matter Quality Matter 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. High quality matter is concentrated and easily extracted. low quality matter is more widely dispersed and more difficult to extract. low quality matter is more widely dispersed and more difficult to extract. Figure 2-8 Slide 42 Fig. 2-8, p. 39 High QualityLow Quality Salt Solid Gas Coal Coal-fired power plant emissions Gasoline Automobile emissions Solution of salt in water Aluminum ore Aluminum can Slide 43 CHANGES IN MATTER Matter 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. When a physical or chemical change occurs, no atoms are created or destroyed. Law of conservation of matter.Law of conservation of matter. Physical change maintains original chemical composition. Physical change maintains original chemical composition. Chemical change involves a chemical reaction which changes the arrangement of the elements or compounds involved. Chemical change involves a chemical reaction which changes the arrangement of the elements or compounds involved. Chemical equations are used to represent the reaction.Chemical equations are used to represent the reaction. Slide 44 Chemical Change Energy is given off during the reaction as a product. Slide 45 p. 39 Reactant(s)Product(s) carbon +oxygen carbon dioxide + energy C +O2O2 CO 2 energy + + black solidcolorless gas + Slide 46 Types of Pollutants Factors that determine the severity of a pollutants effects: chemical nature, concentration, and persistence. Pollutants are classified based on their persistence: Degradable pollutants Degradable pollutants Biodegradable pollutants Biodegradable pollutants Slowly degradable pollutants Slowly degradable pollutants Nondegradable pollutants Nondegradable pollutants Slide 47 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. 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). 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). Slide 48 Animation: Positron-Emission Tomography PLAY ANIMATION Slide 49 Animation: Half-Life PLAY ANIMATION Slide 50 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 Slide 51 Fig. 2-9, p. 41 Uranium-235 Neutron Fission Fragment Fission Fragment Energy n n n n n n Slide 52 Uranium-235 Fig. 2-6, p. 28 Neutron Uranium-235 Energy Fission fragment Fission fragment n n n n n n Energy Stepped Art Slide 53 Video: Isotopes PLAY VIDEO Slide 54 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 Slide 55 Fig. 2-10, p. 42 Neutron + Hydrogen-2 (deuterium nucleus) Hydrogen-3 (tritium nucleus) + ProtonNeutron 100 million C Energy + Helium-4 nucleus Products Reaction Conditions Fuel + Slide 56 Video: Nuclear Energy From ABC News, Environmental Science in the Headlines, 2005 DVD. PLAY VIDEO Slide 57 ENERGY Energy is the ability to do work and transfer heat. Kinetic energy energy in motion Kinetic energy energy in motion heat, electromagnetic radiationheat, electromagnetic radiation Potential energy stored for possible use Potential energy stored for possible use batteries, glucose moleculesbatteries, glucose molecules Slide 58 Animation: Martian Doing Mechanical Work PLAY ANIMATION Slide 59 Electromagnetic Spectrum Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content. Figure 2-11 Slide 60 Fig. 2-11, p. 43 Sun Nonionizing radiationIonizing radiation High energy, short Wavelength Wavelength in meters (not to scale) Low energy, long Wavelength Cosmic rays Gamma Rays X rays Far infrared waves Near ultra- violet waves Visible Waves Near infrared waves Far ultra- violet waves Micro- waves TV waves Radio Waves Slide 61 Electromagnetic Spectrum Organisms vary in their ability to sense different parts of the spectrum. Figure 2-12 Slide 62 Fig. 2-12, p. 43 Energy emitted from sun (kcal/cm 2 /min) Wavelength (micrometers) Ultraviolet Visible Infrared Slide 63 Animation: Visible Light PLAY ANIMATION Slide 64 Fig. 2-13, p. 44 Low-temperature heat (100C or less) for space heating Moderate-temperature heat (1001,000C) for industrial processes, cooking, producing steam, electricity, and hot water Very high-temperature heat (greater than 2,500C) for industrial processes and producing electricity to run electrical devices (lights, motors) Mechanical motion to move vehicles and other things) High-temperature heat (1,0002,500C) for industrial processes and producing electricity Dispersed geothermal energy Low-temperature heat (100C or lower) Normal sunlight Moderate-velocity wind High-velocity water flow Concentrated geothermal energy Moderate-temperature heat (1001,000C) Wood and crop wastes High-temperature heat (1,0002,500C) Hydrogen gas Natural gas Gasoline Coal Food Electricity Very high temperature heat (greater than 2,500C) Nuclear fission (uranium) Nuclear fusion (deuterium) Concentrated sunlight High-velocity wind Source of Energy Relative Energy Quality (usefulness) Energy Tasks Slide 65 ENERGY LAWS: TWO RULES WE CANNOT BREAK The first law of thermodynamics: we cannot create or destroy energy. We can change energy from one form to another. We can change energy from one form to another. The second law of thermodynamics: energy quality always decreases. When energy changes from one form to another, it is always degraded to a more dispersed form. 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. Energy efficiency is a measure of how much useful work is accomplished before it changes to its next form. Slide 66 Animation: Total Energy Remains Constant PLAY ANIMATION Slide 67 Fig. 2-14, p. 45 Chemical energy (food) Solar energy Waste Heat Waste Heat Waste Heat Waste Heat Mechanical energy (moving, thinking, living) Chemical energy (photosynthesis) Slide 68 Animation: Energy Flow PLAY ANIMATION Slide 69 SUSTAINABILITY AND MATTER AND ENERGY LAWS Unsustainable High-Throughput Economies: Working in Straight Lines Converts resources to goods in a manner that promotes waste and pollution. Converts resources to goods in a manner that promotes waste and pollution. Figure 2-15 Slide 70 Fig. 2-15, p. 46 High-quality energy Matter Unsustainable high-waste economy System Throughputs Inputs (from environment) Outputs (into environment) Low-quality energy (heat) Waste and pollution Slide 71 Sustainable Low-Throughput Economies: Learning from Nature Matter-Recycling-and-Reuse Economies: Working in Circles Mimics nature by recycling and reusing, thus reducing pollutants and waste. Mimics nature by recycling and reusing, thus reducing pollutants and waste. It is not sustainable for growing populations. It is not sustainable for growing populations. Slide 72 Fig. 2-16, p. 47 Recycle and reuse Low-quality Energy (heat) Waste and pollution Pollution control Sustainable low-waste economy Waste and pollution Matter Feedback Energy Feedback Inputs (from environment) Energy conservation Matter Energy System Throughputs Outputs (into environment) Slide 73 Animation: Economic Types PLAY ANIMATION