APES Chapter 2

1. APES Chapter 2

2. Science • 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

3. Science • Important scientific tools • Inductive reasoning uses observations and measurements to arrive at a conclusion • Deductive reasoning uses logic to arrive at a conclusion based upon a generalization

4. Science • Scientific theory • Widely tested • Supported by extensive evidence • Accepted by most scientists in a particular area • Scientific law, law of nature is a well-tested & widely accepted description of a natural event • Paradigm shift a change in the framework for theories and laws

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

6. Matter • 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

7. Matter

8. Matter • Subatomic particles • Protons (p) with positive charge and neutrons (0) with no charge in nucleus • Negatively charged electrons (e) orbit the nucleus • Mass number • Protons plus neutrons • Isotopes • Atoms of the same element that differ by mass

9. Matter • Ions • Gain or lose electrons • Form ionic compounds • pH • Measure of acidity • H+ and OH-

10. Matter

11. Matter • Inorganic compounds • Organic compounds • Hydrocarbons and chlorinated hydrocarbons • Simple carbohydrates • Macromolecules: complex organic molecules • Complex carbohydrates • Proteins • Nucleic acids • Lipids

12. Matter

13. Matter • Physical change • Chemical change, chemical reaction • Nuclear change • Natural radioactive decay • Radioisotopes: unstable • Nuclear fission • Nuclear fusion

14. Matter

15. Matter • Law of conservation of matter • Atoms can not be created or destroyed during chemical or physical change • Matter consumption • Matter is converted from one form to another

16. Energy • Kinetic energy • Heat • Transferred by radiation, conduction, or convection • Electromagnetic radiation • Examples: wind, electricity • Potential energy • Stored (latent) energy • Can be changed into kinetic energy

17. Energy • First Law of Thermodynamics • Energy input always equals energy output • Second Law of Thermodynamics • Energy always goes from a more useful to a less useful form when it changes from one form to another • Energy efficiency or productivity

18. Systems • System (a set of components that function and interact in a regular way • System components: • Inputsfrom the environment • Flows, throughputs (within the system) • Outputs to the environment

19. Systems • Positive feedback loop causes a system to change further in the same direction • Loss of vegetation leads to erosion; this leads to further loss of vegetation, etc • Negative, or corrective, feedback loopcauses a system to change in the opposite direction • Recycling/reuse

20. Systems

21. Systems • 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 • Examples include population growth, leaks from toxic waste dumps, global climate change

22. Systems Synergistic interaction, synergy • 2 or more processes that interact to produce an effect greater than the sum of their separate effects • Helpful (caffeine in aspirin) • Harmful (Smoking and inhaling asbestos particles)

23. Systems • Open system- exchanges of matter or energy occur across system boundaries. • Closed system- matter and energy exchanges across system boundaries do not occur