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

2. A. The Nature of Science
Science assumes that events in the natural world follow orderly patterns and that these patterns can be understood
Based on observations of phenomenon, scientists form a scientific hypothesis
Hypothesis — an unconfirmed explanation of an observed phenomenon to be tested
A scientific theory is a verified, believable, widely accepted scientific hypothesis or a related group of scientific hypotheses

3. Scientists use both inductive reasoning and deductive reasoning
Theories are the most reliable knowledge we have about how nature works
A scientific/natural law describes events/actions of nature that reoccur in the same way, over and over again
They always include a degree of uncertainty.
Scientists use both inductive reasoning and deductive reasoning
Inductive reasoning uses specific observations and measurements to arrive at a conclusion
Deductive reasoning uses logic to arrive at a specific conclusion

4. Stepped Art Ask a question Do experiments and collect data
Interpret data
Well-tested and
accepted patterns
In data become
scientific laws
Formulate hypothesis
to explain data
Do more experiments
to test hypothesis
Revise hypothesis
if necessary
Well-tested and
accepted
hypotheses
become
scientific theories
Stepped Art
Fig. 2-3, p. 30

5. Frontier science is scientific results that have not been confirmed;
Sound science results from scientific results that have been well tested and are widely accepted.
Media people mislead us, consider the reliability of the individuals presenting the data.

6. B. Models and Behavior of Systems
Scientists project the behavior of complex systems by developing a model of its inputs, throughputs (flows), and outputs of matter, energy, and information.
Mathematical models consist of one or a series of equations used to describe behavior of a system (e.g. Hurricane behavior)

7. Sustainable low-waste economy Matter Feedback Energy Feedback 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
Figure 2.16
Solutions: lessons from nature. A low-throughput economy, based on energy flow and matter recycling, works with nature to reduce the throughput of matter and energy resources (items shown in green). This is done by (1) reusing and recycling most nonrenewable matter resources, (2) using renewable resources no faster than they are replenished, (3) using matter and energy resources efficiently, (4) reducing unnecessary consumption, (5) emphasizing pollution prevention and waste reduction, and (6) controlling population growth.
Energy Feedback
Fig. 2-16, p. 47

8. Feedback loops can cause a system to do more positive feedback (what it was doing) or negative feedback (in opposite direction)

9. Animation: Feedback Control of Temperature
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ANIMATION

10. A synergistic interaction results in the combined effects interact to amplify the results
smoking magnify the effect of asbestos exposure on lung cancer

11. C. Types and Structure of Matter
Matter is anything that has mass and takes up space
Elements (represented on the periodic table) are the distinctive building blocks of matter
Compounds: two or more different elements held together in fixed proportions by chemical bonds

12. The building blocks of matter are atoms
Each atom has a nucleus containing protons and neutrons and one or more electrons orbit the nucleus.
A proton (p) is positively charged.
A neutron (n) is uncharged.
The electron (e) is negatively charged
Isotopes of an element are various forms of an element that have the same atomic number, but different mass number.
May need to show the difference in atomic number versus atomic mass i.e. Carbon is #6 but mass is 12 and it’s isotope is mass of 14 a two neutron difference.

13. Atoms
Figure 2-4

14. Animation: Subatomic Particles
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ANIMATION

15. Animation: Atomic Number, Mass Number
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ANIMATION

16. An ion is an atom or group of atoms with one or more net positive or negative electrical charges.
e.g. Hydrogen ions (H+), Hydroxide ions (OH- )
Elements known, as metals tend to lose one or more electrons
Elements known, as nonmetals tend to gain more electrons

17. Animation: Ionic Bonds
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ANIMATION

18. Hydrogen ions (H+) in a solution are a measure of how acidic or basic the solution
The amount of a substance in a unit volume of air, water, or other medium is its concentration
The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution

19. Figure 2-5

20. Animation: pH Scale
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ANIMATION

21. Chemical formulas are a type of shorthand to show the type and number of atoms/ions in a compound
Ionic compounds are made up of oppositely charged ions, (Na+ and Cl-).
Compounds made of uncharged atoms are called covalent compounds (CH4).

22. Organic compounds contain carbon atoms combined with one another and with various other atoms such as H+, N+, or Cl-.
Contain at least two carbon atoms combined with each other and with atoms.
Methane (CH4) is the only exception.
All other compounds are inorganic.
Hydrocarbons: compounds of carbon and hydrogen atoms
Chlorinated hydrocarbons: compounds of carbon, hydrogen, and chlorine atoms
Simple carbohydrates: specific types of compounds of carbon, hydrogen and oxygen atoms. (e.g. sugars)

23. Animation: Carbon Bonds
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ANIMATION

24. Large, complex organic molecules (macromolecules) make up the basic molecular units found in living organisms; four major types:
Complex carbohydrates contain two or more monomers of simple sugars
Proteins are formed by linking monomers of amino acids
Nucleic acids are made of sequences of nucleotides
Lipids large organic compounds that are non-polar ex; fats, oils, steroids, and hormones.

25. All living things are composed of cells
Cells of eukaryotic organisms have a membrane, nucleus, and organelles
Cells of prokaryotic organisms have a membrane but no defined nucleus or organelles
Organic molecules are the building blocks of life

26. Animation: Prokaryotic and Eukaryotic Cells
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ANIMATION

27. Matter exists in four states, solid, liquid, gaseous and as plasma
Water can exist in all three forms
Plasma is a high-energy mixture of positively charged ions and negatively charged electrons.
Scientists make artificial plasmas in fluorescent lights, TV and computer screens.

28. Matter can be classified as having high or low quality depending on how useful it is to us as a resource.
High quality matter is concentrated and easily extracted.
low quality matter is more widely dispersed and more difficult to extract.
Figure 2-8

29. Material efficiency/resource productivity describes the total amount of material needed to produce a unit of good/service.

30. D. Changes in Matter
The Law of conservation of matter states that no atoms are created/destroyed during a physical or chemical change
In a physical change, the molecules are organized in different patterns.
In a chemical change, the chemical composition of the elements/compounds change
Chemical equations are used to verify that no atoms are created or destroyed in a chemical reaction

31. Changes in Matter
3 minutes

32. Reactant(s) Product(s) energy energy energy carbon carbon dioxide +
oxygen + C + O2
CO2 +
energy + +
energy
black solid
colorless gas
colorless gas
p. 39

33. Pollutants are classified based on their persistence:
We will always have some pollutants, but can produce less and clean up some that we do produce
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

34. Three types of nuclear change are radioactive decay, nuclear fission, and nuclear fusion.
Radioactive decay is the change of a radioisotope to different isotope by spontaneously emitting fast moving chunks of matter
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)
Exposure to ionizing radiation from this damages cells in two possible ways: genetic damage (mutation of DNA molecules), body cell damage to tissues.
Common half lives : Carbon14 5,760 yrs, U x 108 ,
Listing of Half-lifes;

35. Animation: Half-Life
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ANIMATION

36. Nuclear Changes: Fission
Nuclear fission: nuclei of certain isotopes with large mass numbers are split apart into lighter nuclei when struck by neutrons.
Critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction.
Figure 2-9

37. Stepped Art Fig. 2-6, p. 28 Uranium-235 Energy Fission fragment n
Neutron
Stepped Art
Fig. 2-6, p. 28

38. 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

39. Video: Nuclear Energy
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VIDEO
From ABC News, Environmental Science in the Headlines, 2005 DVD.

40. E. Energy & Energy Laws:
Energy is the capacity to do work and transfer heat; it moves matter
Kinetic energy has mass and speed
Potential energy is stored energy, ready to be used
Potential energy can be changed to kinetic energy

41. Animation: Martian Doing Mechanical Work
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ANIMATION

42. Electromagnetic radiation is energy that travels as a wave, a result of changing electric and magnetic fields
The electromagnetic spectrum describes the range of electromagnetic waves that have different wavelengths and energy content
Organisms vary in there ability to sense different parts of the spectrum.

43. Original Energy Source

44. Solar ejection

45. Sun Ionizing radiation Nonionizing radiation Cosmic rays Gamma Rays
Far
ultra-
violet
waves
Near
ultra-
violet
waves
Near
infrared
waves
Far
infrared
waves
X rays
Visible
Waves
Micro-
waves TV
waves
Radio
Waves
Figure 2.11
The electromagnetic spectrum: the range of electromagnetic waves, which differ in wavelength (distance between successive peaks or troughs) and energy content.
High energy, short
Wavelength
Wavelength in meters
(not to scale)
Low energy, long
Wavelength
Fig. 2-11, p. 43

46. Animation: Visible Light
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ANIMATION

47. The first law of thermodynamics: we cannot create or destroy energy.
We can change energy from one form to another.
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.t

48. Animation: Total Energy Remains Constant
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ANIMATION

49. Mechanical energy (moving, thinking, living)
Chemical
energy
(photosynthesis)
Chemical
energy
(food)
Solar
energy
Waste
Heat
Waste
Heat
Waste
Heat
Waste
Heat
Figure 2.14
The second law of thermodynamics in action in living systems. Each time energy changes from one form to another, some of the initial input of high-quality energy is degraded, usually to low-quality heat that is dispersed into the environment.
Fig. 2-14, p. 45

50. F Sustainability and Matter and Energy Laws
Resource use automatically adds some waste heat/waste to the environment
Advanced industrialized countries have high-throughput (high waste) economies
Eventually consumption will exceed capacity of the environment to dilute/degrade wastes
Recycling and reusing more of earth’s matter resources slows depletion of nonrenewable resources,

51. Shifting to a more sustainable, low-throughput (low-waste) economy is the best long-term solution to environmental/resource problems
Waste less matter, live more simply, slow population growth.