Chapter 2

1. Chapter 2 Systems

2. Easter Island • A closed system • Once a paradise • Tragedy of the commons • Time delay • Exponential devastation • Population crash • Model of the planet

3. Experiments • Blind – do not know what is being taken by subject • Double blind – neither the tester nor the subject know what is being given to the subject • Placebo – harmless sample used as a control and test validity of the group being used

4. Accuracy vs. Precision • Accuracy refers to getting the correct measurement or reading • Precision refers to being able to repeat your performance exactly

5. Good accuracy and good precision Poor accuracy and poor precision Poor accuracy and good precision Fig. 3.3, p. 46

6. Positive feedback loop • Runaway cycle • A change in the system (input) causes the output to increase which causes more input • Ex. Global warming – as temperatures rise from increased CO2, the oceans will release more dissolved CO2 causing the ocean temperatures to rise further.

7. Negative feedback loop • Homeostasis • A change in input creates an output which causes the input to decrease • Ex. As pollution becomes less of a problem, it will bother fewer people, regulations on pollution will become less stringent

8. Rate of metabolic chemical reactions Positive feedback loop Blood temperature in hypothalamus Excess temperature perceived by brain Sweat production by skin Heat in body Heat input from sun and metabolism Heat loss from air cooling skin Negative feedback loop Fig. 3.4, p. 51

9. Time delays in systems • Typical for environmental systems • Do not see/feel the consequence coming until it is too late to avoid • Smoking – years of smoking may lead to cancer and then quitting doesn’t matter, it is too late.

10. Synergistic interactions • When two processes create a stronger effect together than the sum of their individual parts • Ex. Smog – heat and UV radiation from the sun combine with car emissions and create a toxic substance worse than either alone

11. What’s the “matter” • Matter – anything with mass and volume • Elements vs. compounds • Parts of the atom, atomic number, mass number • Ions – positive or negative • Isotopes – watch those neutrons • Molecules – types of bonding ionic, covalent, hydrogen

12. Organic compounds(have carbon) • NOT Carbon Dioxide (exception) • Hydrocarbons – fossil fuels (methane) • Chlorinated hydrocarbons – DDT • Chlorofluorocarbons (CFCs) – Freon • Carbohydrates – glucose C6H12O6

13. pH scale • pH – percent Hydronium • Logarithmic scale from 0 (strong acid) to 14 (strong base) with 7 being neutral • A 2 means 10-2 Hydronium ions in solution or ten times more than a 3 on the scale

14. Fig. 3.7, p. 56

15. Quality matter • High quality matter is easily used by man in terms of creating a product • Low quality matter is difficult to obtain or to convert into usable objects

16. High Quality Low Quality Gas Solid Salt Solution of salt in water Coal Coal-fired power plant emissions Gasoline Automobile emissions Fig. 3.9, p. 57 Aluminum can Aluminum ore

17. Human matter • What are we made of? The human body contains about 100 trillion cells. There is a nucleus inside each human cell (except red blood cells). Each nucleus contains 46 chromosomes, arranged in 23 pairs. One chromosome of every pair is from each parent. The chromosomes are filled with tightly coiled strands of DNA. Genes are segments of DNA that contain instructions to make proteins—the building blocks of life. There are approximately 140,000 genes in each cell, each coded by sequences of nucleotides in its DNA molecules.

18. Forms of energy • Energy is the ability to do work and transfer heat • Kinetic energy – motion • Potential energy – stored energy • High quality is easy to use to do work, such as electricity

19. Sun High energy, short wavelength Low energy, long wavelength Nonionizing radiation Ionizing radiation Cosmic rays Gamma rays X rays Far ultraviolet waves Near ultraviolet waves Visible waves Near infrared waves Far infrared waves microwaves TV waves Radio waves 10-14 10-12 10-8 10-7 10-6 10-5 10-3 10-2 10-1 1 Wavelength in meters (not to scale) Fig. 3.10, p. 58

20. Physical vs chemical changes Reactant(s) Products(s) carbon + oxygen carbon dioxide+ energy C + O2 CO2+ energy O C O C O + energy O black solid colorless gas colorless gas In-text, p. 59

21. Energy absorbed Evaporation And boiling Melting Freezing Condensation solid liquid gas Energy released Fig. 3.5, p. 54

22. Law of conservation of matter • There is “no away” • – matter is changed either physically or chemically, but is still present • We will never run out of matter, only matter in an easily used form

23. The breakdown of matter • Concentration • Persistence – how long will it last? • Degradable – via physical,chemical, or biological • Slowly degradable – (plastics, DDT (takes decades)) • Nondegradable (elements like lead, mercury)

24. Nuclear (not nucular) Changes • Radioactive change (decay) is another possible change to matter • Natural radioactive decay • Nuclear fusion • Nuclear fission

25. Natural radioactive decay • Unstable isotopes (radioisotopes) breakdown at a uniform rate known as its half life • Gives off Gamma rays (ionizing radiation) in the form of alpha (2 protons and 2 neutrons) and beta (electrons) particles • Radioactivity is measured in Curies

26. Sheet of paper Block of wood Concrete wall Alpha Beta Gamma Fig. 3.12, p. 62

27. Don’t eat that, it’s radioactive • In general it takes ten half lives for a radioactive substance to be considered safe. • Plutonium-239 is carcinogenic is minute amounts. If its half-life is 24,000 years, how long do you have to quarantine a sample until it is safe?

28. 1 Fraction of original amount of plutonium-239 left 1/2 1/4 1st half-life 2nd half-life 3rd half-life 1/8 0 Fig. 3.13, p. 62 24,000 48,000 72,000 Time (years)

29. Ionizing Radiation • Harmful radiation resulting in two types of damage • Genetic damage – DNA mutations • Somatic damage – tissue damage, ex. Burns, cataracts, cancer, miscarriage

30. Other 1% Ionizing radiation sources (US) Consumer products 3% Radon 55% Nuclear medicine 4% Medical X rays 10% Space 8% Earth 8% The human body 11% Natural sources 82% Human-generated 18% Fig. 3.14, p. 63

31. Fission vs. Fusion • Nuclear fission involves splitting atoms • Typically a large mass isotope (U235) • When neutrons are shot at nucleus, the nucleus splits releasing energy, and more neutrons • Creates chain reaction • Used in power generation (Nuclear power plants)

32. Fission fragment n n Energy n n Uranium-235 nucleus Unstable nucleus Fission fragment Fig. 3.15, p. 64

33. 235 92 U n 92 36 Kr 235 92 n U n 235 92 U n 141 56 Ba 92 36 Kr n 92 36 Kr n n n n 235 92 n U 141 56 Ba 92 36 Kr n 141 56 Ba 235 92 U n 235 92 U n 141 56 Ba Fig. 3.16, p. 64 235 92 U

34. Fusion is “Da Bomb” • Two light nuclei are slammed together at high speed • Fusing produces new nucleus and releases energy • Typically isotopes of hydrogen are used • This is what is inside a Hydrogen Bomb, like “Fatman and Little Boy”

35. Fuel Reaction Conditions Products D-T Fusion Neutron + + Energy Hydrogen-2 or deuterium nucleus + + + + 100 million ˚C Helium-4 nucleus Hydrogen-3 or tritium nucleus D-D Fusion + + + Helium-3 nucleus Hydrogen-2 or deuterium nucleus Energy + + + + Proton Hydrogen-2 or deuterium nucleus 1 billion ˚C Neutron Neutron Fig. 3.17, p. 64

36. First Law of Thermodynamics • Also called the law of conservation of energy • Energy is neither created nor destroyed but may be converted from one form into another • ENERGY IN = ENERGY OUT

37. Second Law of Thermodynamics • When energy changes form, some energy is degraded in lower quality energy • In other words, heat is lost to the surrounding environment in all energy conversions or transfers (entropy)

38. Second Law of Thermodynamics Mechanical energy (moving, thinking, living) Chemical energy (food) Chemical energy (photosynthesis) Solar energy Waste heat Waste heat Waste heat Waste heat P.S. Also remember heat flows from hot to cold Fig. 3.18, p. 66

39. How does the second law of energy affect life? • If “all” energy comes from the sun, explain why, in terms of the environment, it is better to be a vegetarian than to be a carnivore.

40. The End… finally!