1. LIVING IN THE ENVIRONMENT 17 TH MILLER/SPOOLMAN CHAPTER 2 Science, Matter, Energy, and Systems

2. Core Case Study: A Story About a Forest Hubbard Brook Experimental Forest in New Hampshire Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site) Stripped site: 30-40% more runoff More dissolved nutrients More soil erosion

3. The Effects of Deforestation on the Loss of Water and Soil Nutrients Fig. 2-1, p. 31

4. 2-1 What Do Scientists Do? Concept 2-1 Scientists collect data and develop theories, models, and laws about how nature works.

5. Science Is a Search for Order in Nature Identify a problem Find out what is known about the problem Ask a question to be investigated Gather data through experiments Propose a scientific hypothesis Make testable predictions Keep testing and making observations Accept or reject the hypothesis Scientific theory: well-tested and widely accepted hypothesis

6. Science Is a Search for Order in Nature Make testable predictions Keep testing and making observations Accept or reject the hypothesis Scientific theory: well-tested and widely accepted hypothesis

7. Scientific theory Well-tested and widely accepted hypothesis Stepped Art Test predictions Make testable predictions Accept hypothesis Revise hypothesis Perform an experiment to test predictions Use hypothesis to make testable predictions Propose an hypothesis to explain data Analyze data (check for patterns) Scientific law Well-accepted pattern in data Perform an experiment to answer the question and collect data Ask a question to be investigated Find out what is known about the problem (literature search) Identify a problem Fig. 2-2, p. 33

8. Testing a Hypothesis Fig. 2-3, p. 33

9. Nothing happens when I try to turn on my flashlight. Question: Why didn’t the light come on? Hypothesis: Maybe the batteries are dead. Test hypothesis with an experiment: Put in new batteries and try to turn on the flashlight. Result: Flashlight still does not work. New hypothesis: Maybe the bulb is burned out. Experiment: Put in a new bulb. Result: Flashlight works. Conclusion: New hypothesis is verified. Observation:

10. Characteristics of Science…and Scientists Curiosity Skepticism Reproducibility Peer review Openness to new ideas Critical thinking Creativity

11. Easter Island: Some revisions to a popular environmental story Polynesians arrived about 800 years ago Population may have reached 3000 Used trees in an unsustainable manner, but rats may have multiplied and eaten the seeds of the trees

12. Scientific Theories and Laws Are the Most Important Results of Science Scientific theory Widely tested Supported by extensive evidence Accepted by most scientists in a particular area Scientific law, law of nature A well tested and widely accepted description of what we find happening repeatedly in nature in the same way

13. The Results of Science Can Be Tentative, Reliable, or Unreliable Tentative science (frontier science) Preliminary scientific results that have not been widely tested and accepted Reliable science Consists of data, hypotheses, models, theories and laws that are widely accepted by many “experts” in the particular field of study Unreliable science Hypotheses and results that have not undergone, or have been discarded by widespread peer review

14. Science Has Some Limitations 1.Particular hypotheses, theories, or laws have a high probability of being true while not being absolute 2.Bias can be minimized by scientists 3.Environmental phenomena involve interacting variables and complex interactions 4.Statistical methods may be used to estimate very large or very small numbers 5.Scientific process is limited to the natural world

15. Science Focus: Statistics and Probability Statistics Collect, organize, and interpret numerical data Probability The chance that something will happen or be valid Need large enough sample size

16. 2-2 What Is Matter? Concept 2-2 Matter consists of elements and compounds, which are in turn made up of atoms, ions, or molecules.

17. Matter Consists of Elements and Compounds Matter Has mass and takes up space Elements Unique properties Cannot be broken down chemically into other substances Compounds Two or more different elements bonded together in fixed proportions

18. Gold and Mercury Are Chemical Elements Fig. 2-4a, p. 38

19. Chemical Elements Used in The Book Table 2-1, p. 38

20. Atoms, Ions, and Molecules Are the Building Blocks of Matter Atomic theory All elements are made of atoms Subatomic particles Protons with positive charge and neutrons with no charge in nucleus Negatively charged electrons orbit the nucleus Atomic number Number of protons in nucleus Mass number Number of protons plus neutrons in nucleus

21. Model of a Carbon-12 Atom Fig. 2-5, p. 39

22. Atoms, Ions, and Molecules Are the Building Blocks of Matter Isotopes Same element, different number of protons Ions Gain or lose electrons Form ionic compounds pH Measure of acidity H + and OH -

23. Chemical Ions Used in This Book Table 2-2, p. 40

24. pH Scale Supplement 5, Figure 4

25. Loss of NO 3 − from a Deforested Watershed Fig. 2-6, p. 40

26. Undisturbed (control) watershed Disturbed (experimental) watershed Nitrate (NO 3 – ) concentration (milligrams per liter) Year 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 40 60 20

27. Compounds Used in This Book Table 2-3, p. 40

28. Organic Compounds Are the Chemicals of Life Organic compounds- at least two carbon atoms (except methane= CH 4 ) Hydrocarbons and chlorinated hydrocarbons Simple carbohydrates Macromolecules: complex organic molecules Complex carbohydrates Proteins Nucleic acids Lipids Inorganic compounds all compounds that are not considered organic

29. Glucose Structure Supplement 4, Fig. 4

30. Amino Acids and Proteins Supplement 4, Fig. 8

31. Nucleotide Structure in DNA and RNA Supplement 4, Fig. 9

32. DNA Double Helix Structure and Bonding Supplement 4, Fig. 10

33. Fatty Acid Structure and Triglyceride Supplement 4, Fig. 11

34. Matter Comes to Life through Genes, Chromosomes, and Cells Cells: fundamental units of life; all organisms are composed of one or more cells Genes Sequences of nucleotides within DNA Instructions for proteins Create inheritable traits Chromosomes: composed of many genes

35. Cells, Nuclei, Chromosomes, DNA, and Genes Fig. 2-7, p. 42

36. A human body contains trillions of cells, each with an identical set of genes. Each human cell (except for red blood cells) contains a nucleus. 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 proteins—the building blocks of life.

37. Some Forms of Matter Are More Useful than Others High-quality matter Highly concentrated Near earth’s surface High potential as a resource Low-quality matter Not highly concentrated Deep underground or widely dispersed Low potential as a resource

38. Examples of Differences in Matter Quality Fig. 2-8, p. 42

39. High QualityLow Quality SolidGas Salt Solution of salt in water Coal Coal-fired power plant emissions Gasoline Automobile emissions Aluminum canAluminum ore

40. 2-3 What Happens When Matter Undergoes Change? Concept 2-3 Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed (the law of conservation of matter).

41. Matter Undergoes Physical, Chemical, and Nuclear Changes Physical change No change in chemical composition Chemical change, chemical reaction Change in chemical composition Reactants and products Nuclear change Natural radioactive decay Radioisotopes: unstable Nuclear fission Nuclear fusion

42. Types of Nuclear Changes Fig. 2-9, p. 43

43. Fig. 2-9a, p. 43 Radioactive decay occurs when nuclei of unstable isotopes spontaneously emit fast-moving chunks of matter (alpha particles or beta particles), high- energy radiation (gamma rays), or both at a fixed rate. A particular radioactive isotope may emit any one or a combination of the three items shown in the diagram. Radioactive isotope Radioactive decay Gamma rays Alpha particle (helium-4 nucleus) Beta particle (electron)

44. Fig. 2-9b, p. 43 Nuclear fission Uranium-235 Neutron Energy Fission fragment n n n n n n Energy Fission fragment Radioactive isotope Radioactive decay occurs when nuclei of unstable isotopes spontaneously emit fast-moving chunks of matter (alpha particles or beta particles), high- energy radiation (gamma rays), or both at a fixed rate. A particular radioactive isotope may emit any one or a combination of the three items shown in the diagram.

45. Fig. 2-9c, p. 43 Nuclear fusion occurs when two isotopes of light elements, such as hydrogen, are forced together at extremely high temperatures until they fuse to form a heavier nucleus and release a tremendous amount of energy. Hydrogen-3 (tritium nucleus) 100 million °C Reaction conditions Neutron Energy Products Neutron Nuclear fusion Fuel Hydrogen-2 (deuterium nucleus) Helium-4 nucleus Proton

46. We Cannot Create or Destroy Matter Law of conservation of matter Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed

47. 2-4 What is Energy and What Happens When It Undergoes Change? Concept 2-4A When energy is converted from one form to another in a physical or chemical change, no energy is created or destroyed (first law of thermodynamics). Concept 2-4B Whenever energy is changed from one form to another in a physical or chemical change, we end up with lower-quality or less usable energy than we started with (second law of thermodynamics).

48. Energy Comes in Many Forms Kinetic energy- Energy assoc. with motion Flowing water Wind Heat- moving atoms, ions, molecules Transferred by radiation, conduction, or convection Electromagnetic radiation- wave energy that results from a change in electrical and magnetic fields Potential energy Stored energy Can be changed into kinetic energy

49. Wind’s Kinetic Energy Moves This Turbine Fig. 2-10, p. 44

50. The Electromagnetic Spectrum Fig. 2-11, p. 45

51. Visible light Gamma rays X rays Shorter wavelengths and higher energy Longer wavelengths and lower energy UV radiation Infrared radiation MicrowavesTV, Radio waves Wavelengths (not to scale) 0.0010.010.11100.1101000.11101 100 NanometersMicrometersCentimetersMeters

52. Potential Energy Fig. 2-12, p. 45

53. Energy Comes in Many Forms Sun provides 99% of earth’s energy Warms earth to comfortable temperature Plant photosynthesis Winds Hydropower Biomass Fossil fuels: oil, coal, natural gas

54. Nuclear Energy to Electromagnetic Radiation Fig. 2-13, p. 46

55. Fossil fuels Fig. 2-14a, p. 46

56. Some Types of Energy Are More Useful Than Others High-quality energy High capacity to do work Concentrated High-temperature heat Strong winds Fossil fuels Low-quality energy Low capacity to do work Dispersed

57. Ocean Heat Is Low-Quality Energy Fig. 2-15, p. 47

58. Energy Changes Are Governed by Two Scientific Laws First Law of Thermodynamics Law of conservation of energy Energy is neither created nor destroyed in physical and chemical changes Second Law of Thermodynamics Energy always goes from a more useful to a less useful form when it changes from one form to another Light bulbs and combustion engines are very inefficient: produce wasted heat

59. Energy-Wasting Technologies Fig. 2-16a, p. 48

60. 2-5 What Are Systems and How Do They Respond to Change? Concept 2-5 Systems have inputs, flows, and outputs of matter and energy, and feedback can affect their behavior.

61. Systems Have Inputs, Flows, and Outputs System Set of components that interact in a regular way Human body, earth, the economy Inputs from the environment Flows (throughputs) of matter and energy Outputs to the environment

62. Inputs, Throughput, and Outputs of an Economic System Fig. 2-17, p. 48

63. Systems Respond to Change through Feedback Loops Positive feedback loop Causes system to change further in the same direction Can cause major environmental problems Negative, or corrective, feedback loop Causes system to change in opposite direction

64. Positive Feedback Loop Fig. 2-18, p. 49

65. Negative Feedback Loop Fig. 2-19, p. 50

66. Time Delays Can Allow a System to Reach a Tipping Point Time delays vary Between the input of a feedback stimulus and the response to it Tipping point- threshold level Causes a shift in the behavior of a system Melting of polar ice Population growth

67. System Effects Can Be Amplified through Synergy Synergistic interaction (synergy) Two or more processes combine in such a way that combined effect is greater than the two separate effects Helpful Studying with a partner Harmful E.g., Smoking and inhaling asbestos particles

68. The Usefulness of Models for Studying Systems 1.Identify major components of systems and interactions within system, and then write equations 2.Use computer to describe behavior, based on the equations 3.Compare projected behavior with known behavior Can use a good model to answer “if-then“ questions

69. Three Big Ideas 1.There is no away. Matter does not go away. It can only change physical or chemical state. (Law of Cons. of Matter) 2.You cannot get something for nothing. You cannot get more energy out than you put in (Law of Cons. of Energy, 1 st Law of Thermodynamics)) 3.You cannot break even. When energy is converted you will always end up with lower-quality, or less usable energy than you started with (2 nd Law of Thermodynamics)