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Chapter 2 Science, Systems, Matter, and Energy Matter High-Q Energy Low-Q Energy.

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1 Chapter 2 Science, Systems, Matter, and Energy Matter High-Q Energy Low-Q Energy

2 Chapter Overview Questions What is science, and what do scientists do? What is science, and what do scientists do? What are major components and behaviors of complex systems? 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 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? What types of changes can matter undergo and what scientific law governs matter?

3 Chapter Overview Questions (contd) What are the major forms of energy, and what makes energy useful as a resource? 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? 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? 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: Purpose of science: Discover order in the natural world and make predictions about what is likely to happen in the future Discover order in the natural world and make predictions about what is likely to happen in the future What do scientists do? 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. next

5 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

6 Scientific Theories and Laws: The Most Important Results of Science Scientific Theory Scientific Theory Widely tested and accepted hypothesis. Widely tested and accepted hypothesis. Atomic Theory Scientific Law Scientific Law What we find happening over and over again in nature. What we find happening over and over again in nature. Gravitational Constant Gravitational Constant next Peer Review

7 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 Peer Review Process… …Brutal!

8 Testing Hypotheses Scientists test hypotheses using controlled experiments and constructing mathematical models. 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 multivariate and are hard to control in an experiment. Most environmental phenomena are multivariate and are hard to control in an experiment. Models are used to analyze interactions of variables.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)

10 Scientific Reasoning and Creativity Inductive reasoning 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 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.

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. 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). 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. Unreliable science a.k.a. junk science is presented as sound science without going through the rigors of peer-review.

12 Paradigm Shift Paradigm Shift- a complete change in worldview as a result of new information Paradigm Shift- a complete change in worldview as a result of new information ExEarth-centered to sun-centered view of solar system ExEarth-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. 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.

14 MODELS AND BEHAVIOR OF SYSTEMS Usefulness of models 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. Poorly defined models of a system result in unreliable results…models are continuously tested against new real data 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. 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) 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). 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 Negative Feedback LoopFeedback Loop brother & sister yelling hunger & eatingbrother & sister yelling hunger & eating Draw each loop and determine if it represents positive or negative feedback: thirst & drinking 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. 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 cancer E.g. tipping over in a chair; the recent economic troubles; a smoker gets cancer Prolonged delays may prevent a negative feedback loop from occurring. Prolonged delays may prevent a negative feedback loop from occurring. Synergy- Processes and feedbacks in a system can interact to amplify the results. 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. E.g. smoking exacerbates the effect of asbestos exposure on lung cancer.

18 Feedback Loops: Some negative feedback loops have explicit goals Some negative feedback loops have explicit goals Balancing Metersticks Balancing Metersticks Body Temperature Body Temperature Blood CO 2 levels Blood CO 2 levels Etc. Etc.

19 TYPES AND STRUCTURE OF MATTER Elements and Compounds 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. Carbon, hydrogen, oxygen, nitrogen, etc Carbon, hydrogen, oxygen, nitrogen, etc 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. CO 2, H 2 O, C 6 H 12 O 6 CO 2, H 2 O, C 6 H 12 O 6

20 Atoms Figure 2-4

21 Ions An ion is an atom or group of atoms with one or more net positive or negative electrical charges. 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 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 - )

22 The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution. The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution. 0= strongest acids 7 = neutral 14 = strongest base pH adjectives: *acids are acidic *bases are basic a.k.a. alkaline Figure 2-5

23

24 Compounds and Chemical Formulas Chemical formulas are shorthand ways to show the atoms and ions in a chemical compound. 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).

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 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. Organic compounds 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 (without C) are inorganic. All other compounds (without C) are inorganic.

26 Organic Compounds: Carbon Rules Hydrocarbons: compounds of carbon and hydrogen atoms (e.g. methane (CH 4 )). 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 Cl 5 )). Chlorinated hydrocarbons: compounds of carbon, hydrogen, and chlorine atoms (e.g. DDT (C 14 H 9 Cl 5 )). Simple carbohydrates: certain types of compounds of carbon, hydrogen, and oxygen (e.g. glucose (C 6 H 12 O 6 )). Simple carbohydrates: certain types of compounds of carbon, hydrogen, and oxygen (e.g. glucose (C 6 H 12 O 6 )). Complex carbohydrates: chains of glucose, such as starch or cellulose 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. 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

28 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)

29 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)

30 Macromolecules, DNA, Genes and Chromosomes Large, complex organic molecules (macromolecules) make up the basic molecular units found in living organisms. 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

31 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

32 States of Matter The atoms, ions, and molecules that make up matter are found in three physical states: 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. 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).

33 Matter Quality Matter can be classified as having high or low quality depending on how useful it is to us as a resource. 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

34 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

35 CHANGES IN MATTER Matter can change from one physical form to another or change its chemical composition. 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.

36 Chemical Change Energy is given off during the reaction as a product. Energy is given off during the reaction as a product. Mass does not change (Conservation of Matter) Mass does not change (Conservation of Matter)

37 Three Types of Atomic Nuclear Changes Radioactive decay Radioactive decay Fission- splitting atoms (like uranium) Fission- splitting atoms (like uranium) First atomic bombs First atomic bombs All nuclear power plants All nuclear power plants Fusion- fusing atoms together (like hydrogen) Fusion- fusing atoms together (like hydrogen) H-Bomb H-Bomb Sun and all other stars Sun and all other stars 100 million degrees Celsius to begin reaction 100 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. Nuclear fission: nuclei of certain isotopes with large mass numbers are split apart into lighter nuclei when struck by neutrons. Figure 2-9

39 Uranium-235 Fig. 2-6, p. 28 Neutron Uranium-235 Energy Fission fragment Fission fragment n n n n n n Energy Stepped Art

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. 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 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 +

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. 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).

43 Matter: Types of Pollutants Factors that determine the severity of a pollutants effects: chemical nature, concentration, and persistence. Factors that determine the severity of a pollutants effects: chemical nature, concentration, and persistence. Pollutants are classified based on their persistence: Pollutants are classified based on their persistence: Degradable pollutants- can be broken down Degradable pollutants- can be broken down Biodegradable pollutants- e.g. human sewageBiodegradable pollutants- e.g. human sewage Slowly degradable pollutants- e.g. most plastics; chlorinated hydrocarbons like DDTSlowly degradable pollutants- e.g. most plastics; chlorinated hydrocarbons like DDT Nondegradable (a.k.a. persistent) pollutants- e.g. lead, mercury, arsenic Nondegradable (a.k.a. persistent) pollutants- e.g. lead, mercury, arsenic

44 ENERGY Energy is the ability to do work and transfer heat. Energy is the ability to do work and transfer heat. Kinetic energy – Kinetic energy – energy in motionenergy in motion heat, electromagnetic radiation heat, electromagnetic radiation Potential energy – Potential energy – stored for possible usestored for possible use batteries, glucose molecules, any food, water behind a dam batteries, 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. Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content. Next

46 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

47 Electromagnetic Spectrum Organisms vary in their ability to sense different parts of the spectrum. Organisms vary in their ability to sense different parts of the spectrum. Next

48 Fig. 2-12, p. 43 Energy emitted from sun (kcal/cm 2 /min) Wavelength (micrometers) Ultraviolet Visible Infrared

49 Fig. 2-13, p. 44 Low-temperature heat (100°C or less) for space heating Moderate-temperature heat (100–1,000°C) for industrial processes, cooking, producing steam, electricity, and hot water Very high-temperature heat (greater than 2,500°C) for industrial processes and producing electricity to run electrical devices (lights, motors) Mechanical motion to move vehicles and other things) High-temperature heat (1,000–2,500°C) for industrial processes and producing electricity Dispersed geothermal energy Low-temperature heat (100°C or lower) Normal sunlight Moderate-velocity wind High-velocity water flow Concentrated geothermal energy Moderate-temperature heat (100–1,000°C) Wood and crop wastes High-temperature heat (1,000–2,500°C) Hydrogen gas Natural gas Gasoline Coal Food Electricity Very high temperature heat (greater than 2,500°C) Nuclear fission (uranium) Nuclear fusion (deuterium) Concentrated sunlight High-velocity wind Source of Energy Relative Energy Quality (usefulness) Energy Tasks

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) 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. We can change energy from one form to another. burning Cheeto: Chemical thermal & electromagnetic The second law of thermodynamics: energy quality always decreases (a.k.a. Law of Entropy) The 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. 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.

51 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) Second Law of Thermodynamics

52 SUSTAINABILITY AND MATTER AND ENERGY LAWS Unsustainable High-Throughput Economies: Working in Straight Lines 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. Next

53 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

54 Fig. 2-10, p. 44 Heat Energy Inputs ThroughputsOutputs Energy resources Matter resources Information Economy Goods and services Waste and pollution

55 Sustainable Low-Throughput Economies: Learning from Nature Matter-Recycling-and-Reuse Economies: Working in Circles 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. Only sustainable if population stabilizes (ZPG)! Why not?

56 Fig. 2-11, p. 45

57 Fig. 2-12, p. 45

58 p. 49

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