Chapter 4: Matter

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Chapter 4 Matter Energy

• Scientific Thinking
• Limitations of Science
• The Structure of Matter
• Energy Principles

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Limitations of Science

• Accuracy of data and measurements
• Accuracy of sampling Why a statistics course is
  a good idea
• Frontier science vs. consensus science
• Scientists are people too and have opinions, but
  these should NOT affect their science
• Cant make social or moral decisions

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The Structure of Matter

• From the very small to the very large...

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Energy Principles

• Two laws of Thermodynamics
• 1) Energy quantity is constant
• 2) Energy quality decreases with use

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First Law of Thermodynamics

• Energy can neither be created nor destroyed, it
  can only be changed from one form into another
• Energy can have different qualitiesgt degree of
  usefulness
• High quality is easily usable for work, e.g.
  electricity
• Lower quality is less useful for work, e.g.,
  normal sunlight

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First Law implies...

• Theres no magic energy machine, no perpetual
  motion, you cant get something for nothing
• Ex California energy crisis of Summer 01
• Politics cant make energy...

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Second Law of Thermodynamics

• Energy quality (NOT quantity) always decreases
  when energy is transferred, some energy is
  converted to useless heat (low quality energy)
• Ex Light bulb gets hot, you want light!
• Implies that a continuing supply of high quality
  energy is necessary. For ecosystems, this energy
  source is the Sun, and is concentrated by
  photosynthesis

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For conservation purposes, high quality energy...

• Should be used only for high quality tasks
• That is, only where its really needed
• Example, electricity (high quality) should be
  used for electronics, electric motors, etc.
• Should NOT be used for a low quality task, like
  space heating...

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In nature, PHOTOSYNTHESIS is critical...

• Concentrates low quality dispersed sunlight
• Into high quality chemical energy of
  carbohydrates
• Provides the energy at the base of the Food Chain

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