Chapter 2<br />Science, Systems, Matter, and Energy<br />
Chapter Overview Questions<br />What is science, and what do scientists do?<br />What are major components and behaviors o...
Chapter Overview Questions (cont’d)<br />What are the major forms of energy, and what makes energy useful as a resource?<b...
Updates Online<br />	The latest references for topics covered in this section can be found at the book companion website. ...
Video: The Throw Away Society<br />This video clip is available in CNN Today Videos for Environmental Science, 2004, Volum...
Core Case Study: Environmental Lesson from Easter Island<br />Thriving society<br />15,000 people by 1400.<br />Used resou...
THE NATURE OF SCIENCE<br />What do scientists do?<br />Collect data.<br />Form hypotheses.<br />Develop theories, models a...
Ask a question<br />Do experiments<br />and collect data<br />Interpret data<br />Well-tested and<br />accepted patterns<b...
Ask a question<br />Do experiments<br />and collect data<br />Interpret data<br />Well-tested and<br />accepted patterns<b...
Scientific Theories and Laws: The Most Important Results of Science<br />Scientific Theory<br />Widely tested and accepted...
Research results<br />Scientific paper<br />Peer review by<br />experts in field<br />Paper<br />rejected<br />Paper accep...
Testing Hypotheses<br />Scientists test hypotheses using controlled experiments and constructing mathematical models.<br /...
Scientific Reasoning and Creativity<br />Inductive reasoning<br />Involves using specific observations and measurements to...
Frontier Science, Sound Science, and Junk Science<br />Frontier science has not been widely tested (starting point of peer...
Limitations of Environmental Science<br />Inadequate data and scientific understanding can limit and make some results con...
MODELS AND BEHAVIOR OF SYSTEMS<br />Usefulness of models<br />Complex systems are predicted by developing a model of its i...
Feedback Loops: How Systems Respond to Change<br />Outputs of matter, energy, or information fed back into a system can ca...
Feedback Loops: <br />Negative feedback can take so long that a system reaches a threshold and changes.<br />Prolonged del...
TYPES AND STRUCTURE OF MATTER<br />Elements and Compounds<br />Matter exists in chemical forms as elements and compounds.<...
Atoms<br />Figure 2-4<br />
Ions<br />An ion is an atom or group of atoms with one or more net positive or negative electrical charges.<br />The numbe...
The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution.<br />Figure 2-5<br />
Compounds and Chemical Formulas<br />Chemical formulas are shorthand ways to show the atoms and ions in a chemical compoun...
Organic Compounds: Carbon Rules<br />Organic compounds contain carbon atoms combined with one another and with various oth...
Organic Compounds: Carbon Rules<br />Hydrocarbons: compounds of carbon and hydrogen atoms (e.g. methane (CH4)).<br />Chlor...
Cells: The Fundamental Units of Life<br />Cells are the basic structural and functional units of all forms of life.<br />P...
(a) Prokaryotic Cell<br />DNA(information storage, no nucleus)<br />Cell membrane<br />(transport of<br />raw materials an...
(b) Eukaryotic Cell<br />Energy conversion<br />Nucleus <br />(information<br />storage)<br />Protein <br />construction<b...
Macromolecules, DNA, Genes and Chromosomes<br />Large, complex organic molecules (macromolecules) make up the basic molecu...
A human body contains trillions of cells, each with an identical set of genes.<br />There is a nucleus inside each human c...
A human body contains trillions<br />of cells, each with an identical<br />set of genes.<br />There is a nucleus inside ea...
States of Matter<br />The atoms, ions, and molecules that make up matter are found in three physical states:<br />solid, l...
Matter Quality<br />Matter can be classified as having high or low quality depending on how useful it is to us as a resour...
Matter Quality<br />It is the measure of how useful a form of matter is as a resource<br />Based on AVAILABILITY and CONCE...
Aluminum Can<br />A more concentrated, Higher Quality matter than aluminum ore that contains the same amount of aluminum<b...
High Quality<br />Low Quality<br />Solid<br />Gas<br />Solution of salt in water<br />Salt<br />Coal<br />Coal-fired power...
CHANGES IN MATTER<br />Matter can change from one physical form to another or change its chemical composition.<br />When a...
Chemical Change<br />Energy is given off during the reaction as a product.<br />
Reactant(s)<br />Product(s)<br />energy<br />carbon dioxide<br />carbon<br />+<br />oxygen<br />+<br />energy<br />+<br />...
Types of Pollutants<br />Factors that determine the severity of a pollutant’s effects:<br />Chemical nature<br />Concentra...
Types of Pollutants<br />Degradable pollutants<br />Non - persistent<br />Can be broken down completely or reduced to acce...
ENERGY<br />Energy is the ability to do work and transfer heat.<br />Kinetic energy – energy in motion<br />heat, electrom...
3 Ways Heat Can Be Transferred<br />Convection<br />When warmer particles rise and the fall as then cool down<br />Conduct...
Electromagnetic Spectrum<br />Many different forms of electromagnetic radiation exist, each having a different wavelength ...
Sun<br />Nonionizing radiation<br />Ionizing radiation<br />Near<br />infrared<br />waves<br />Far<br />infrared <br />wav...
EM Spectrum<br />Ionizing radiation<br />Cosmic rays, gamma rays, X-rays, UV rays <br />Contain enough energy to knock ele...
Electromagnetic Spectrum<br />Organisms vary in their ability to sense different parts of the spectrum.<br />Figure 2-12<b...
Energy emitted from sun (kcal/cm2/min)<br />Visible<br />Infrared<br />Ultraviolet<br />Wavelength (micrometers)<br />Fig....
Relative<br />Energy Quality<br />(usefulness)<br />Source of Energy<br />Energy Tasks<br />Electricity<br />Very high tem...
ENERGY LAWS: TWO RULES WE CANNOT BREAK<br />The first law of thermodynamics: we cannot create or destroy energy.<br />We c...
Laws of Thermodynamics<br />Cannot create or destroy energy, only transfer or change form<br />When energy changes form, s...
Mechanicalenergy(moving,thinking,living)<br />Chemical <br />energy<br />(photosynthesis)<br />Chemical<br />energy<br />(...
ISOTOPES! <br />Atoms with the same atomic number but with different atomic masses are called isotopes<br />Changing the #...
Radioactive Isotopes<br />As the difference b/t p+ and n. in the nucleus increases, the nucleus becomes more unstable<br /...
Isotopes of the Element Potassium with a Known Natural Abundance<br />Mass #  Natural Abundance        Half-life <br />39 ...
Isotopes continued<br />Radiation can be dangerous in large amounts but in small amounts it can be useful in science<br />...
Nuclear Changes: Radioactive Decay<br />Natural radioactive decay: unstable isotopes spontaneously emit fast moving chunks...
Half-life (HL)<br />Time needed for one-half of the nuclei to decay to form a different isotope<br />Emits radiation to fo...
Half Life continued<br />Use HL to estimate how long a sample radioactive isotope must be stored in a safe container befor...
Nuclear Changes: Fission<br />Nuclear fission: nuclei of certain isotopes with large mass numbers are split apart into lig...
Uranium-235<br />Uranium-235<br />Uranium-235<br />Energy<br />Fission<br />Fragment<br />Uranium-235<br />n<br />n<br />N...
Uranium-235<br />Uranium-235<br />Uranium-235<br />Energy<br />Fission<br />fragment<br />Uranium-235<br />n<br />n<br />n...
Nuclear Changes: Fusion<br />Nuclear fusion: two isotopes of light elements are forced together at extremely high temperat...
Reaction<br />Conditions<br />Products<br />Fuel<br />Proton<br />Neutron<br />Energy<br />Hydrogen-2<br />(deuterium nucl...
SUSTAINABILITY AND MATTER AND ENERGY LAWS<br />Unsustainable High-Throughput Economies: Working in Straight Lines<br />Con...
System<br />Throughputs<br />Inputs<br />(from environment)<br />Outputs<br />(into environment)<br />Unsustainable<br />h...
Sustainable Low-Throughput Economies: Learning from Nature<br />Matter-Recycling-and-Reuse Economies: Working in Circles<b...
Mechanicalenergy(moving,thinking,living)<br />Chemical <br />energy<br />(photosynthesis)<br />Chemical<br />energy<br />(...
Inputs <br />(from environment)<br />System<br />Throughputs<br />Outputs<br />(into environment)<br />Energy<br />conserv...
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Chemistry and bio apes ppt chaper 2

  1. 1. Chapter 2<br />Science, Systems, Matter, and Energy<br />
  2. 2. Chapter Overview Questions<br />What is science, and what do scientists do?<br />What are major components and behaviors of complex systems?<br />What are the basic forms of matter, and what makes matter useful as a resource?<br />What types of changes can matter undergo and what scientific law governs matter?<br />
  3. 3. Chapter Overview Questions (cont’d)<br />What are the major forms of energy, and what makes energy useful as a resource?<br />What are two scientific laws governing changes of energy from one form to another?<br />How are the scientific laws governing changes of matter and energy from one form to another related to resource use, environmental degradation and sustainability?<br />
  4. 4. Updates Online<br /> The latest references for topics covered in this section can be found at the book companion website. Log in to the book’s e-resources page at www.thomsonedu.com to access InfoTrac articles.<br />InfoTrac: Underwater Microscope Finds Biological Treasures in Subtropical Ocean. Ascribe Higher Education News Service, June 26, 2006.<br />InfoTrac: In Bacterial Diversity, Amazon Is a 'Desert'; Desert Is an 'Amazon'. Ascribe Higher Education News Service, Jan 9, 2006.<br />InfoTrac: Making MGP wastes beneficial. Bob Paulson. Pollution Engineering, June 2006 v38 i6 p20(5).<br />NASA: Nitrogen Cycle<br />Environmental Literacy Council: Phosphorous Cycle<br />National Sustainable Agriculture Information Service: Nutrient Cycles<br />
  5. 5. Video: The Throw Away Society<br />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.<br />
  6. 6. Core Case Study: Environmental Lesson from Easter Island<br />Thriving society<br />15,000 people by 1400.<br />Used resources faster than could be renewed<br />By 1600 only a few trees remained.<br />Civilization collapsed<br />By 1722 only several hundred people left.<br />Figure 2-1<br />
  7. 7. THE NATURE OF SCIENCE<br />What do scientists do?<br />Collect data.<br />Form hypotheses.<br />Develop theories, models and laws about how nature works.<br />Figure 2-2<br />
  8. 8. Ask a question<br />Do experiments<br />and collect data<br />Interpret data<br />Well-tested and<br />accepted patterns<br />in data become<br />scientific laws<br />Formulate hypothesis<br />to explain data<br />Do more experiments<br />to test hypothesis<br />Revise hypothesis<br />if necessary<br />Well-tested and<br />accepted hypotheses<br />become<br />scientific theories<br />Fig. 2-2, p. 29<br />
  9. 9. Ask a question<br />Do experiments<br />and collect data<br />Interpret data<br />Well-tested and<br />accepted patterns<br />In data become<br />scientific laws<br />Formulate hypothesis<br />to explain data<br />Do more experiments<br />to test hypothesis<br />Revise hypothesis<br />if necessary<br />Well-tested and<br />accepted<br />hypotheses<br />become<br />scientific theories<br />Stepped Art<br />Fig. 2-3, p. 30<br />
  10. 10. Scientific Theories and Laws: The Most Important Results of Science<br />Scientific Theory<br />Widely tested and accepted hypothesis.<br />Scientific Law<br />What we find happening over and over again in nature.<br />Figure 2-3<br />
  11. 11. Research results<br />Scientific paper<br />Peer review by<br />experts in field<br />Paper<br />rejected<br />Paper accepted<br />Paper published in<br />scientific journal<br />Research evaluated<br />by scientific community<br />Fig. 2-3, p. 30<br />
  12. 12. Testing Hypotheses<br />Scientists test hypotheses using controlled experiments and constructing mathematical models.<br />Variables or factors influence natural processes<br />Single-variable experiments involve a control and an experimental group.<br />Most environmental phenomena are multivariable and are hard to control in an experiment.<br />Models are used to analyze interactions of variables.<br />
  13. 13. Scientific Reasoning and Creativity<br />Inductive reasoning<br />Involves using specific observations and measurements to arrive at a general conclusion or hypothesis.<br />Bottom-up reasoning going from specific to general.<br />Deductive reasoning<br />Uses logic to arrive at a specific conclusion.<br />Top-down approach that goes from general to specific.<br />
  14. 14. Frontier Science, Sound Science, and Junk Science<br />Frontier science has not been widely tested (starting point of peer-review).<br />Sound science consists of data, theories and laws that are widely accepted by experts.<br />Junk science is presented as sound science without going through the rigors of peer-review.<br />
  15. 15. Limitations of Environmental Science<br />Inadequate data and scientific understanding can limit and make some results controversial.<br />Scientific testing is based on disproving rather than proving a hypothesis.<br />Based on statistical probabilities.<br />
  16. 16. MODELS AND BEHAVIOR OF SYSTEMS<br />Usefulness of models<br />Complex systems are predicted by developing a model of its inputs, throughputs (flows), and outputs of matter, energy and information.<br />Models are simplifications of “real-life”.<br />Models can be used to predict if-then scenarios.<br />
  17. 17. Feedback Loops: How Systems Respond to Change<br />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.<br />Positive feedback loop causes a system to change further in the same direction (e.g. erosion)<br />Negative (corrective) feedback loop causes a system to change in the opposite direction (e.g. seeking shade from sun to reduce stress).<br />
  18. 18. Feedback Loops: <br />Negative feedback can take so long that a system reaches a threshold and changes.<br />Prolonged delays may prevent a negative feedback loop from occurring.<br />Processes and feedbacks in a system can (synergistically) interact to amplify the results.<br />E.g. smoking exacerbates the effect of asbestos exposure on lung cancer.<br />
  19. 19. TYPES AND STRUCTURE OF MATTER<br />Elements and Compounds<br />Matter exists in chemical forms as elements and compounds.<br />Elements (represented on the periodic table) are the distinctive building blocks of matter.<br />Compounds: two or more different elements held together in fixed proportions by chemical bonds.<br />
  20. 20. Atoms<br />Figure 2-4<br />
  21. 21. Ions<br />An ion is an atom or group of atoms with one or more net positive or negative electrical charges.<br />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 <br />Hydrogen ions (H+), Hydroxide ions (OH-)<br />Sodium ions (Na+), Chloride ions (Cl-)<br />
  22. 22. The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution.<br />Figure 2-5<br />
  23. 23. Compounds and Chemical Formulas<br />Chemical formulas are shorthand ways to show the atoms and ions in a chemical compound. <br />Combining Hydrogen ions (H+) and Hydroxide ions (OH-) makes the compound H2O (dihydrogen oxide, a.k.a. water).<br />Combining Sodium ions (Na+) and Chloride ions (Cl-) makes the compound NaCl (sodium chloride a.k.a. salt).<br />
  24. 24. Organic Compounds: Carbon Rules<br />Organic compounds contain carbon atoms combined with one another and with various other atoms such as H+, N+, or Cl-.<br />Contain at least two carbon atoms combined with each other and with atoms.<br />Methane (CH4) is the only exception.<br />All other compounds are inorganic.<br />
  25. 25. Organic Compounds: Carbon Rules<br />Hydrocarbons: compounds of carbon and hydrogen atoms (e.g. methane (CH4)).<br />Chlorinated hydrocarbons: compounds of carbon, hydrogen, and chlorine atoms (e.g. DDT (C14H9Cl5)).<br />Simple carbohydrates: certain types of compounds of carbon, hydrogen, and oxygen (e.g. glucose (C6H12O6)).<br />
  26. 26. Cells: The Fundamental Units of Life<br />Cells are the basic structural and functional units of all forms of life.<br />Prokaryotic cells (bacteria) lack a distinct nucleus.<br />Eukaryotic cells (plants and animals) have a distinct nucleus.<br />Figure 2-6<br />
  27. 27. (a) Prokaryotic Cell<br />DNA(information storage, no nucleus)<br />Cell membrane<br />(transport of<br />raw materials and <br />finished products)<br />Protein construction<br />and energy conversion<br />occur without specialized<br />internal structures<br />Fig. 2-6a, p. 37<br />
  28. 28. (b) Eukaryotic Cell<br />Energy conversion<br />Nucleus <br />(information<br />storage)<br />Protein <br />construction<br />Cell membrane<br />(transport of raw<br />materials and<br />finished products)<br />Packaging<br />Fig. 2-6b, p. 37<br />
  29. 29. Macromolecules, DNA, Genes and Chromosomes<br />Large, complex organic molecules (macromolecules) make up the basic molecular units found in living organisms.<br />Complex carbohydrates<br />Proteins<br />Nucleic acids<br />Lipids<br />Figure 2-7<br />
  30. 30. A human body contains trillions of cells, each with an identical set of genes.<br />There is a nucleus inside each human cell (except red blood cells).<br />Each cell nucleus has an identical set of chromosomes, which are found in pairs.<br />A specific pair of chromosomes contains one chromosome from each parent.<br />Each chromosome contains a long DNA molecule in the form of a coiled double helix. <br />Genes are segments of DNA on <br />chromosomes that contain instructions <br />to make proteins—the building blocks <br />of life. <br />The genes in each cell are coded by sequences of nucleotides in their DNA molecules. <br />Fig. 2-7, p. 38<br />
  31. 31. A human body contains trillions<br />of cells, each with an identical<br />set of genes.<br />There is a nucleus inside each<br />human cell (except red blood cells).<br />Each cell nucleus has an identical<br />set of chromosomes, which are<br />found in pairs.<br />A specific pair of chromosomes<br />contains one chromosome from<br />each parent.<br />Each chromosome contains a long<br />DNA molecule in the form of a coiled<br />double helix.<br />Genes are segments of DNA on<br />chromosomes that contain instructions<br />to make proteins—the building blocks<br />of life.<br />The genes in each cell are coded<br />by sequences of nucleotides in<br />their DNA molecules.<br />Stepped Art<br />Fig. 2-7, p. 38<br />
  32. 32. States of Matter<br />The atoms, ions, and molecules that make up matter are found in three physical states:<br />solid, liquid, gaseous.<br />A fourth state, plasma, is a high energy mixture of positively charged ions and negatively charged electrons.<br />The sun and stars consist mostly of plasma.<br />Scientists have made artificial plasma (used in TV screens, gas discharge lasers, florescent light).<br />
  33. 33. Matter Quality<br />Matter can be classified as having high or low quality depending on how useful it is to us as a resource.<br />High quality matter is concentrated and easily extracted.<br />low quality matter is more widely dispersed and more difficult to extract.<br />Figure 2-8<br />
  34. 34. Matter Quality<br />It is the measure of how useful a form of matter is as a resource<br />Based on AVAILABILITY and CONCENTRATION<br />High Quality<br />Easy to extract<br />Found near earth’s surface<br />Great potential for use as a material resource<br />Low Quality<br />Dilute<br />Usually deep underground or dispersed in the ocean or atmosphere<br />Has little potential for use as material resource<br />
  35. 35. Aluminum Can<br />A more concentrated, Higher Quality matter than aluminum ore that contains the same amount of aluminum<br />Less energy, water and energy to recycle an aluminum can compared to making a brand new aluminum can<br />
  36. 36. High Quality<br />Low Quality<br />Solid<br />Gas<br />Solution of salt in water<br />Salt<br />Coal<br />Coal-fired power plant emissions<br />Gasoline<br />Automobile emissions<br />Aluminum can<br />Aluminum ore<br />Fig. 2-8, p. 39<br />
  37. 37. CHANGES IN MATTER<br />Matter can change from one physical form to another or change its chemical composition.<br />When a physical or chemical change occurs, no atoms are created or destroyed.<br />Law of conservation of matter.<br />Physical change maintains original chemical composition.<br />Different spatial arrangement<br />Chemical change involves a chemical reaction which changes the arrangement of the elements or compounds involved.<br />Chemical equations are used to represent the reaction.<br />Rearrangement of atoms<br />
  38. 38. Chemical Change<br />Energy is given off during the reaction as a product.<br />
  39. 39. Reactant(s)<br />Product(s)<br />energy<br />carbon dioxide<br />carbon<br />+<br />oxygen<br />+<br />energy<br />+<br />O2<br />C<br />CO2<br />+<br />energy<br />+<br />+<br />black solid<br />colorless gas<br />colorless gas<br />p. 39<br />
  40. 40. Types of Pollutants<br />Factors that determine the severity of a pollutant’s effects:<br />Chemical nature<br />Concentration<br />ppm-parts per million…<br />One part pollutant to a million parts of liquid, gas, or solid mixture it is part of<br />Persistence<br />How long it stays in water, air, soil, body<br />Pollutants are classified based on their persistence:<br />Degradable pollutants<br />Biodegradable pollutants<br />Slowly degradable pollutants<br />Nondegradable pollutants<br />
  41. 41. Types of Pollutants<br />Degradable pollutants<br />Non - persistent<br />Can be broken down completely or reduced to acceptable levels by natural physical, chemical or biological processes<br />Biodegradable pollutants<br />Complex chemicals that specialized living organisms (certain bacteria) can break down into simpler chemicals (ie human sewage)<br />Slowly degradable pollutants<br />Persistent pollutant that last for a decade or longer (ie DDT pesticide)<br />Nondegradable pollutants<br />Chemical that cannot be broken down by natural processes (lead, mercury, arsenic) <br />
  42. 42. ENERGY<br />Energy is the ability to do work and transfer heat.<br />Kinetic energy – energy in motion<br />heat, electromagnetic radiation<br />Potential energy – stored for possible use<br />batteries, glucose molecules<br />
  43. 43. 3 Ways Heat Can Be Transferred<br />Convection<br />When warmer particles rise and the fall as then cool down<br />Conduction<br />Particles move and transfer energy to particles around them, until they are all heated to the point where they are moving so fast they are too hot to touch<br />Radiation<br />When heat from the hot/heated material radiates to the surrounding air<br />
  44. 44.
  45. 45. Electromagnetic Spectrum<br />Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content.<br />Figure 2-11<br />
  46. 46. Sun<br />Nonionizing radiation<br />Ionizing radiation<br />Near<br />infrared<br />waves<br />Far<br />infrared <br />waves<br />Near<br />ultra-<br />violet<br />waves<br />Far<br />ultra-<br />violet<br />waves<br />Cosmic<br />rays<br />Gamma<br />Rays<br />Visible<br />Waves<br />TV<br />waves<br />Radio<br />Waves<br />X rays<br />Micro-<br />waves<br />High energy, short<br />Wavelength<br />Wavelength in meters<br />(not to scale)<br />Low energy, long<br />Wavelength<br />Fig. 2-11, p. 43<br />
  47. 47. EM Spectrum<br />Ionizing radiation<br />Cosmic rays, gamma rays, X-rays, UV rays <br />Contain enough energy to knock electrons off of atoms and create positively charged particles<br />Result is highly reactive electrons and ions…DANGEROUS!<br />Genetic damage<br />Cause disruptions in DNA that is passed down to offspring<br />Somatic damage<br />Causes damage to tissue structure<br />Burns, miscarriages, cataracts, cancers<br />Nonionizing radiation<br />Not enough energy to knock off electrons and create ions<br />
  48. 48. Electromagnetic Spectrum<br />Organisms vary in their ability to sense different parts of the spectrum.<br />Figure 2-12<br />
  49. 49. Energy emitted from sun (kcal/cm2/min)<br />Visible<br />Infrared<br />Ultraviolet<br />Wavelength (micrometers)<br />Fig. 2-12, p. 43<br />
  50. 50. Relative<br />Energy Quality<br />(usefulness)<br />Source of Energy<br />Energy Tasks<br />Electricity<br />Very high temperature heat<br /> (greater than 2,500°C)<br />Nuclear fission (uranium)<br />Nuclear fusion (deuterium)<br />Concentrated sunlight<br />High-velocity wind<br />Very high-temperature heat (greater than 2,500°C) for industrial processes and producing electricity to run electrical devices (lights, motors)<br />High-temperature heat<br /> (1,000–2,500°C)<br />Hydrogen gas<br />Natural gas<br />Gasoline<br />Coal<br />Food<br />Mechanical motion to move<br /> vehicles and other things) <br />High-temperature heat<br /> (1,000–2,500°C) for<br /> industrial processes and<br /> producing electricity<br />Normal sunlight<br />Moderate-velocity wind<br />High-velocity water flow<br />Concentrated geothermal energy<br />Moderate-temperature heat<br /> (100–1,000°C)<br />Wood and crop wastes<br />Moderate-temperature heat <br /> (100–1,000°C) for <br /> industrial processes, cooking, producing <br /> steam, electricity, and <br /> hot water<br />Dispersed geothermal energy<br />Low-temperature heat<br /> (100°C or lower)<br />Low-temperature heat<br /> (100°C or less) for<br /> space heating<br />Fig. 2-13, p. 44<br />
  51. 51. ENERGY LAWS: TWO RULES WE CANNOT BREAK<br />The first law of thermodynamics: we cannot create or destroy energy.<br />We can change energy from one form to another.<br />The second law of thermodynamics: energy quality always decreases.<br />When energy changes from one form to another, it is always degraded to a more dispersed form.<br />Energy efficiency is a measure of how much useful work is accomplished before it changes to its next form.<br />
  52. 52. Laws of Thermodynamics<br />Cannot create or destroy energy, only transfer or change form<br />When energy changes form, some energy is always degraded to lower quality, more dispersed, less useful forms of energy (more useful to less useful)<br />
  53. 53.
  54. 54. Mechanicalenergy(moving,thinking,living)<br />Chemical <br />energy<br />(photosynthesis)<br />Chemical<br />energy<br />(food)<br />Solar<br />energy<br />Waste<br />Heat<br />Waste<br />Heat<br />Waste<br />Heat<br />Waste<br />Heat<br />Fig. 2-14, p. 45<br />
  55. 55. ISOTOPES! <br />Atoms with the same atomic number but with different atomic masses are called isotopes<br />Changing the # of neutrons in an atom will affect the…<br />MASS NUMBER= protons + neutrons<br />Isotopes of an element have the same # of p+ and e-…so they behave the same CHEMICALLY<br />The average of all the mass #s of the isotopes of an element give us that decimal on the periodic table (Average Atomic Mass)<br />
  56. 56.
  57. 57.
  58. 58. Radioactive Isotopes<br />As the difference b/t p+ and n. in the nucleus increases, the nucleus becomes more unstable<br />When p=n , nucleus is stable…<br />When n>p or n<p, nucleus is unstable<br />Nucleus will give off tiny amounts of energy to become stable (protons or neutrons)<br />Radiation=energy<br />Radioactive=when something gives off energy<br />
  59. 59. Isotopes of the Element Potassium with a Known Natural Abundance<br />Mass # Natural Abundance Half-life <br />39 93.2581% Stable <br />40 0.0117% 1.265×10+9 years <br />41 6.7302% Stable<br />
  60. 60. Isotopes continued<br />Radiation can be dangerous in large amounts but in small amounts it can be useful in science<br />Geology-determine age of fossils and rocks<br />Medicine-treat cancer and detect cell processes (tracers)<br />PET scans, CT scans, MRI<br />Commercial-kill bacteria that spoils certain foods<br />
  61. 61. Nuclear Changes: Radioactive Decay<br />Natural radioactive decay: unstable isotopes spontaneously emit fast moving chunks of matter (alphaorbeta particles), high-energy radiation (gamma rays), or both at a fixed rate.<br />Radiation is commonly used in energy production and medical applications.<br />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).<br />
  62. 62. Half-life (HL)<br />Time needed for one-half of the nuclei to decay to form a different isotope<br />Emits radiation to form different isotope<br />Decay continues until stable nuclei is produced…forms various radioactive isotopes<br />Each radioactive isotope has a characteristic HL<br />HL cannot be changed by temperature, pressure, chemical rxns, or other known factors <br />
  63. 63. Half Life continued<br />Use HL to estimate how long a sample radioactive isotope must be stored in a safe container before it decays to what is considered a safe level<br />General rule: takes about 10 half-lives to reach this “safe” level<br />Radioactive Iodine-131<br />Concentrated in thyroid gland<br />HL= 8 days<br />How long to reach a safe level?<br />10 x 8 days = 80 days <br />Radioactive Plutonium-239<br />Produced in nuclear reactors and used as explosive in nuclear weapons<br />HL= 24,000 years<br />How long to reach a safe level?<br />10 x 24,000= 240,000 years<br />
  64. 64.
  65. 65.
  66. 66. Nuclear Changes: Fission<br />Nuclear fission: nuclei of certain isotopes with large mass numbers are split apart into lighter nuclei when struck by neutrons.<br />Figure 2-9<br />
  67. 67. Uranium-235<br />Uranium-235<br />Uranium-235<br />Energy<br />Fission<br />Fragment<br />Uranium-235<br />n<br />n<br />Neutron<br />n<br />n<br />Uranium-235<br />Energy<br />Energy<br />n<br />n<br />Uranium-235<br />Fission<br />Fragment<br />Uranium-235<br />Energy<br />Uranium-235<br />Uranium-235<br />Uranium-235<br />Fig. 2-9, p. 41<br />
  68. 68. Uranium-235<br />Uranium-235<br />Uranium-235<br />Energy<br />Fission<br />fragment<br />Uranium-235<br />n<br />n<br />n<br />Neutron<br />n<br />Energy<br />Energy<br />Uranium-235<br />n<br />Uranium-235<br />n<br />Fission<br />fragment<br />Uranium-235<br />Energy<br />Uranium-235<br />Uranium-235<br />Uranium-235<br />Stepped Art<br />Fig. 2-6, p. 28<br />
  69. 69. Nuclear Changes: Fusion<br />Nuclear fusion: two isotopes of light elements are forced together at extremely high temperatures until they fuse to form a heavier nucleus.<br />Figure 2-10<br />
  70. 70. Reaction<br />Conditions<br />Products<br />Fuel<br />Proton<br />Neutron<br />Energy<br />Hydrogen-2<br />(deuterium nucleus)<br />+<br />100<br />million °C<br />+<br />Helium-4 nucleus<br />+<br />+<br />Hydrogen-3<br />(tritium nucleus)<br />Neutron<br />Fig. 2-10, p. 42<br />
  71. 71. SUSTAINABILITY AND MATTER AND ENERGY LAWS<br />Unsustainable High-Throughput Economies: Working in Straight Lines<br />Converts resources to goods in a manner that promotes waste and pollution.<br />Figure 2-15<br />
  72. 72. System<br />Throughputs<br />Inputs<br />(from environment)<br />Outputs<br />(into environment)<br />Unsustainable<br />high-waste <br />economy<br />High-quality energy<br />Low-quality energy (heat)<br />Matter<br />Waste and pollution<br />Fig. 2-15, p. 46<br />
  73. 73. Sustainable Low-Throughput Economies: Learning from Nature<br />Matter-Recycling-and-Reuse Economies: Working in Circles<br />Mimics nature by recycling and reusing, thus reducing pollutants and waste.<br />It is not sustainable for growing populations.<br />
  74. 74. Mechanicalenergy(moving,thinking,living)<br />Chemical <br />energy<br />(photosynthesis)<br />Chemical<br />energy<br />(food)<br />Solar<br />energy<br />Waste<br />Heat<br />Waste<br />Heat<br />Waste<br />Heat<br />Waste<br />Heat<br />Fig. 2-14, p. 45<br />
  75. 75. Inputs <br />(from environment)<br />System<br />Throughputs<br />Outputs<br />(into environment)<br />Energy<br />conservation<br />Low-quality <br />Energy<br />(heat)<br />Energy<br />Sustainable<br />low-waste <br />economy<br />Waste <br />and<br />pollution<br />Waste <br />and <br />pollution<br />Pollution<br />control<br />Matter<br />Recycle<br />and <br />reuse<br />Matter <br />Feedback<br />Energy Feedback<br />Fig. 2-16, p. 47<br />

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