Chapter 2

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

2. Chapter Overview Questions • What is science, and what do scientists do? • 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 types of changes can matter undergo and what scientific law governs matter?

3. Chapter Overview Questions (cont’d) • 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? • 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. Updates Online 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. • InfoTrac: Underwater Microscope Finds Biological Treasures in Subtropical Ocean. Ascribe Higher Education News Service, June 26, 2006. • InfoTrac: In Bacterial Diversity, Amazon Is a 'Desert'; Desert Is an 'Amazon'. Ascribe Higher Education News Service, Jan 9, 2006. • InfoTrac: Making MGP wastes beneficial. Bob Paulson. Pollution Engineering, June 2006 v38 i6 p20(5). • NASA: Nitrogen Cycle • Environmental Literacy Council: Phosphorous Cycle • National Sustainable Agriculture Information Service: Nutrient Cycles

5. Video: The Throw Away Society • 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.

6. Core Case Study: Environmental Lesson from Easter Island • Thriving society • 15,000 people by 1400. • Used resources faster than could be renewed • By 1600 only a few trees remained. • Civilization collapsed • By 1722 only several hundred people left. Figure 2-1

7. THE NATURE OF SCIENCE • What do scientists do? • Collect data. • Scientist Answer Questions & Solve Problems • Form hypotheses. • Develop theories, models and laws about how nature works. Figure 2-2

8. Scientific Theories and Laws: The Most Important Results of Science • Scientific Theory • Widely tested and accepted hypothesis. • Has evidence that supports it. • Scientific Law • What we find happening over and over again in nature. • Fact / Always True Figure 2-3

9. Important Features of Scientific Process • Skepticism • Scientists tend to be highly skepticle of new data until they can be verified • Peer Review • Scientist working in the same field examine & criticize work of colleges either through Journals or Conferences. • Reproducibility • Experiments/Data should be reporducable by other scientists.

10. Testing Hypotheses • Scientists test hypotheses using controlled experiments and constructing mathematical models. • Variables or factors influence natural processes • Single-variable experiments involve a control and an experimental group. • Most environmental phenomena are multivariable and are hard to control in an experiment. • Models are used to analyze interactions of variables.

11. Scientific Reasoning and Creativity • Inductive reasoning • Involves using specific observations and measurements to arrive at a general conclusion or hypothesis. • Bottom-up reasoning going from specific to general. • Deductive reasoning • Uses logic to arrive at a specific conclusion. • Top-down approach that goes from general to specific.

12. Controlled Experiments • Controlled experiments limit the number of variables to testing primarily one variable. • Control group lacks variable (independent variable) and experimental group has variable. Q- Why are controlled experiments not effective when analyzing environmental phenomena?

13. Frontier Science, Sound Science, and Junk Science • Frontier science has not been widely tested (starting point of peer-review). • Sound science consists of data, theories and laws that are widely accepted by experts. • Junk science is presented as sound science without going through the rigors of peer-review.

14. Limitations of Environmental Science • Inadequate data and scientific understanding can limit and make some results controversial. • Scientists will rarely say 100%! • Note- Realize that opportunists can take advantage of morally correct scientists.

15. MODELS AND BEHAVIOR OF SYSTEMS • Usefulness of models • 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 can be used to predict if-then scenarios.

16. States of Matter • The atoms, ions, and molecules that make up matter are found in three physical states: • solid, liquid, gaseous. • 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. • Scientists have made artificial plasma (used in TV screens, gas discharge lasers, florescent light).

17. Types of Pollutants • Factors that determine the severity of a pollutant’s effects: chemical nature, concentration, and persistence. • Pollutants are classified based on their persistence: • Degradable pollutants • Biodegradable pollutants • Slowly degradable pollutants • Nondegradable pollutants

18. Synergistic Interaction • A synergisitc interaction occurs when tow or more processes interact so that the combined effect is greater than the sum of their individual effects when separate. • Smokers- 10x the risk of lung cancer • Asbestos exposure- 5x the risk of lung cancer • Exposure to Both- 50x

19. Nuclear Changes: Radioactive Decay • 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. • 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).

20. Nuclear Changes: Fission • Nuclear fission: nuclei of certain isotopes with large mass numbers are split apart into lighter nuclei when struck by neutrons. Figure 2-9

21. 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. Figure 2-10

22. ENERGY • Energy is the ability to do work and transfer heat. • Kinetic energy – energy in motion • heat, electromagnetic radiation • Potential energy – stored for possible use • batteries, glucose molecules

23. Electromagnetic Spectrum • Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content. Figure 2-11

24. Electromagnetic Spectrum • Organisms vary in their ability to sense different parts of the spectrum. Figure 2-12

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

26. ENERGY LAWS: TWO RULES WE CANNOT BREAK • The first law of thermodynamics: we cannot create or destroy energy. • Environmentally- We cannot get something for nothing in terms of energy quantity.. • The second law of thermodynamics: energy quality always decreases. • 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. • When energy changes form one form to another- there is a decrease in energy quality- so less work can be accomplished.

27. Mechanicalenergy(moving,thinking,living) Chemical energy (photosynthesis) Chemical energy (food) Solar energy Waste Heat Waste Heat Waste Heat Waste Heat Fig. 2-14, p. 45

28. The Thermo Lesson- the best way to get more energy is to stop wasting almost half of the energy we use! • Methods of Reducing Energy Waste: • Driving gas efficient cars • Living in well insulated houses • Energy efficient lights • Energy efficient heating & cooling • Energy efficient appliances • Running appliances from sun (renewable energy)

29. SUSTAINABILITY AND MATTER AND ENERGY LAWS • Unsustainable High-Throughput Economies: Working in Straight Lines • Converts resources to goods in a manner that promotes waste and pollution. Figure 2-15

30. System Throughputs Inputs (from environment) Outputs (into environment) Unsustainable high-waste economy High-quality energy Low-quality energy (heat) Matter Waste and pollution Fig. 2-15, p. 46

31. Sustainable Low-Throughput Economies: Learning from Nature • Matter-Recycling-and-Reuse Economies: Working in Circles • Mimics nature by recycling and reusing, thus reducing pollutants and waste. • It is not sustainable for growing populations.

32. Inputs (from environment) System Throughputs Outputs (into environment) Energy conservation Low-quality Energy (heat) Energy Sustainable low-waste economy Waste and pollution Waste and pollution Pollution control Matter Recycle and reuse Matter Feedback Energy Feedback Fig. 2-16, p. 47

33. Sustainable Low Throughput Economics- Learning from Nature! • We can live more sustainably by reducing the throughput of matter and energy in our economies, not wasting matter and energy resources, recycling and reusing most of the matter resources we use, and stabilizing the size of our population.