Science, Matter, Energy, and Systems

1. Science, Matter, Energy, and Systems Chapter 2

2. Core Case Study: Carrying Out a Controlled Scientific Experiment • F. Herbert Bormann, Gene Likens, et al.: Hubbard Brook Experimental Forest in NH (U.S.) • Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site)

3. Stepped Art Fig. 2-1, p. 28

4. 2-1 What Is Science? • 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 (1) • Identify a problem • Find out what is known about the problem • Ask a question to be investigated • Gather data • Hypothesize • Make testable predictions • Keep testing and making observations • Accept or reject the hypothesis

6. Science Is a Search for Order in Nature (2) • Important features of the scientific process • Curiosity • Skepticism • Peer review • Reproducibility • Openness to new ideas

7. Scientists Use Reasoning, Imagination, and Creativity to Learn How Nature Works • Important scientific tools • Inductive reasoning • Deductive reasoning • Scientists also use • Intuition • Imagination • Creativity

8. Identify a problem The Scientific Process Find out what is known about the problem (literature search) Ask a question to be investigated Perform an experiment to answer the question and collect data Scientific law Well-accepted pattern in data Analyze data (check for patterns) Propose an hypothesis to explain data Use hypothesis to make testable predictions Perform an experiment to test predictions Make testable predictions Accept hypothesis Revise hypothesis Test predictions Scientific theory Well-tested and widely accepted hypothesis Fig. 2-2, p. 30

9. Scientific Theories and Laws Are the Most Important Results of Science • Scientific hypothesis: a possible and testable explanation of what is observed in nature (edu. Guess) • Scientific theory • Supported by extensive evidence (tested many times) • Accepted by most scientists in a particular area • Explains • Scientific law, law of nature • Based on countless observations, tests • Describes

10. Read guest essay on global warming The Scientific Consensus About Global Warming John Harte

11. What is Global Warming? • Talking about the warming of the air atmosphere closest to ground. • More energy from the sun is kept at surface of earth than usual • Scientist are looking at some fundamental questions: • Is this actually occurring? (1⁰C increase in 10yrs) • Did humans cause this (cars, burning forests which add greenhouse gases like CO2 to atmo) • What could be result? (complex Q, complex A)

12. Economics/Politics/Ethics and Science • Any other possible causes? • Yes, changes in the Sun, Volcanoes, variation in earth’s orbit • Has this happened in the past, before humans? • Yes, many times • Ramifications and Blame? • Industries, Nations, Consumers • Scare Tactic? • Big business wants to paint warnings as a method of societal controlby government and shift the blame/concern

13. Stepped Art Fig. 19-7, p. 507

14. The Results of Science Can Be Tentative, Reliable, or Unreliable • Tentative science, frontier science (hypothesis) • Reliable science (theory) • Unreliable science (a theory based on false, misleading or no evidence, faith)

15. Environmental Science Has Some Limitations • Particular hypotheses, theories, or laws have a high probability of being true while not being absolute • Bias has to be minimized by scientists, for validity • Statistical methods may be used to estimate very large or very small numbers • Environmental phenomena involve many interacting variables and complex interactions, testability limitations • Scientific process is limited to the natural world (can not prove or disprove ethical or moral questions)

16. Science Focus: Statistics and Probability • Statistics • Collect, organize, and interpret numerical data • Probability • The chance that something will happen or be valid

17. Animation: pH scale

18. 2-2 What Is Matter? • Concept 2-2 Matter consists of elements and compounds, which are in turn made up of atoms, and/or molecules.

19. What is matter? Is everything made out of matter? Explain your answer.

20. Matter • Has mass and takes up space

21. What is the difference between elements, compounds and mixtures?

22. Matter Consists of Elements and Compounds Elements • Unique properties • Cannot be broken down chemically into other substances Compounds • Two or more different elements chemically bonded together in fixed proportion Mixtures: 2 or more elements, compounds or other mixtures physically mixed together

23. Elements you might consider important environmentally

24. Elements Important to the Study of Environmental Science

25. What is a compound? What is a mixture? • Orange Juice • Ketchup • Distilled Water • Steel • Water from a drinking fountain

26. What is the smallest amount of an element you can have that has all of its properties?

27. Model of a Carbon-12 Atom

28. Animation: Subatomic particles

29. Atoms, Ions, and Molecules Are the Building Blocks of Matter (1) • Atomic theory • Subatomic particles • Protons (p) with positive charge and neutrons (n) with no charge in nucleus (all the mass) • Negatively charged electrons (e) orbit the nucleus (almost no mass)

30. Numbers in chemistry • Atomic number • # of protons in each atom • Every element has a different # of protons • Mass number • Protons plus neutrons

31. Need a Periodic Table • How many protons does Helium have? Argon? • What is the atomic number of Mercury, Nitrogen? • How many electrons does a stable atom of Oxygen have, how do you know? • What is the mass number of the most common form of Carbon, Lead

32. Animation: Atomic number, mass number

33. Atoms, Ions, and Molecules Are the Building Blocks of Matter (2) • Isotopes • Number of neutrons vary, properties same • Most common version founded by rounding atomic mass • Ions • Gain or lose electrons (exteme bonding) • Form ionic compounds

34. Need a periodic table • What is the most common isotope of Sulfur? Magnesium? • Determine how many electrons are lost or gained when atom of Fluorine or Boron is ionized • How are the most common ions of Oxygen and Lithium written

35. Animation: Isotopes

36. Animation: Ionic bonds

37. Chemical Formulas • SO42- • 2H20 • Chemical formula • “Recipe” for 1 molecule of a chemical Compound • Letters • Numbers • Signs

38. Ions Important to the Study of Environmental Science

39. Why are ions important? • Reactivity • Ions with an 1 extra electron or lacking one electron react more strongly • The stronger the reaction means more energy is released or absorbed • Greater effects

40. Loss of NO3−from a Deforested Watershed

41. Atoms, Ions, and Molecules Are the Building Blocks of Matter (3) • Molecule • Two or more atoms of the same or different elements held together by chemical bonds

42. Compounds Important to the Study of Environmental Science

43. Animation: Carbon bonds

44. pH the acid test • pH • Measure of acidity # of Hydrogen ions in a certain volume of a solution • Solution can be neutral , acidic, or basic • Defined by relative amounts of H+ and OH- • Something on either end of scale has a tendency to react strongly • Scale is exponential in amount, 10x for each step

45. Acid lab

46. Organic Compounds Are the Chemicals of Life • Organic compounds: contain 2 + Carbon atoms • 1 exception: Methane CH4 • Types • Hydrocarbons and chlorinated hydrocarbons • Simple carbohydrates • Macromolecules: complex organic molecules • Complex carbohydrates • Proteins • Nucleic acids • Lipids • Inorganic compounds: any other compound not organic

47. Arrange in terms of size • An Artery • Cell • Chromosomes • DNA Molecules • Electron • Genes • Nucleus (in terms of cells, not atoms) • One Atom • Proton

48. 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. Stepped Art Fig. 2-5, p. 38

49. Matter Comes to Life through Genes, Chromosomes, and Cells • Cells: fundamental units of life • Genes: sequences of nucleotides within the DNA , instructions for 1 trait • Chromosomes: composed of many genes

50. Matter Occurs in Various Physical Forms • Solid • Liquid • Gas (plasma)