Science, Matter, Energy, and Systems

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Science, Matter, Energy, and Systems

• Chapter 2

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Core Case Study Carrying Out a Controlled
Scientific Experiment

• F. Herbert Bormann, Gene Likens, et al. Hubbard
  Brook Experimental Forest in NH (U.S.)
• Compared the loss of water and nutrients from an
  uncut forest (control site) with one that had
  been stripped (experimental site)

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The Effects of Deforestation on the Loss of Water
and Soil Nutrients
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2-1 What Is Science?

• Concept 2-1 Scientists collect data and develop
  theories, models, and laws about how nature
  works.

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Science Is a Search for Order in Nature (1)

• Science an endeavor to discover how nature
  works and to use that knowledge to make
  predictions about what is likely to happen in
  nature
• Cause-and-Effect Patterns
• Scientific Process
• 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

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Science Is a Search for Order in Nature (2)

• Important features of the scientific process
• Curiosity
• Skepticism
• Peer review
• Reproducibility
• Openness to new ideas

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The Scientific Process
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Science Focus Easter Island Revisions to a
Popular Environmental Story

• Some revisions in a popular environmental story
• Polynesians arrived about 800 years ago
• Population may have reached 3000
• Used trees in an unsustainable manner, but rats
  may have multiplied and eaten the seeds of the
  trees

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Video ABC News Easter Island
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Scientists Use Reasoning, Imagination, and
Creativity to Learn How Nature Works

• Important scientific tools
• Inductive reasoning using specific observations
  and measurements to arrive at a general
  conclusion or hypothesis bottom-up reasoning
  (specific to general)
• Deductive reasoning using logic to arrive at a
  specific conclusion based on a generalization or
  premise top-down reasoning (general to
  specific)
• Scientists also use
• Intuition
• Imagination
• Creativity

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Scientific Theories and Laws Are the Most
Important Results of Science

• Scientific theory overwhelming body of
  observation and measurements support a scientific
  hypothesis
• Widely tested
• Supported by extensive evidence
• Accepted by most scientists in a particular area
• Scientific law, law of nature well tested and
  widely accepted description of what we find
  happening over and over again in the same way in
  nature
• Paradigm shift new discoveries and ideas
  overthrow a well accepted theory or law majority
  of scientists accept a new paradigm

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Science Focus The Scientific Consensus over
Global Warming

• How much has the earths atmosphere warmed during
  the last 50 years?
• How much of this warming is due to human
  activity?
• How much is the atmosphere likely to warm in the
  future?
• Will this affect climate?
• 1988 Intergovernmental Panel on Climate Change
  (IPCC)

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The Results of Science Can Be Tentative,
Reliable, or Unreliable

• Tentative science, frontier science preliminary
  results not widely tested or accepted by peer
  review not considered reliable
• Reliable science data, hypotheses, theories,
  and laws that are widely accepted based on
  self-correcting testing, peer review,
  reproducibility, and debate
• Unreliable science hypotheses and results are
  presented as reliable without having undergone
  peer review or have been discarded by peer review

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Environmental Science Has Some Limitations

• Science can disprove things, but never prove
  anything absolutely due to degree of uncertainty
  in measurements, models, and observations
• Establish particular hypotheses, theories, or
  laws have a high probability of being true while
  not being absolute
• Bias can be minimized by high standards and peer
  review
• Statistical methods may be used to estimate very
  large or very small numbers
• Environmental phenomena involve interacting
  variables and complex interactions too costly so
  create models
• Scientific process is limited to the natural
  world

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Science Focus Statistics and Probability

• Statistics
• Collect, organize, and interpret numerical data
• Probability
• The chance that something will happen or be valid

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2-2 What Is Matter?

• Concept 2-2 Matter consists of elements and
  compounds, which are in turn made up of atoms,
  ions, or molecules.

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Matter Consists of Elements and Compounds

• 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

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Elements Important to the Study of Environmental
Science
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Atoms, Ions, and Molecules Are the Building
Blocks of Matter (1)

• Atomic theory - all elements are made of atoms
  (smallest unit of matter to which an element can
  be divided and retain chemical properties)
• Subatomic particles
• Protons (p) with positive charge and neutrons (0)
  with no charge in nucleus
• Negatively charged electrons (e) orbit the
  nucleus
• Atomic number protons in nucleus
• Mass number - protons plus neutrons
• Isotopes form of elements with same atomic
  number but different mass numbers

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Model of a Carbon-12 Atom
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Atoms, Ions, and Molecules Are the Building
Blocks of Matter (2)

• Ions atom or group of atoms with one or more
  net positive or negative charges
• Gain or lose electrons
• Form ionic compounds
• Nitrate
• pH
• Measure of acidity
• H and OH-
• Pure water pH of 7, neutral solution

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Animation pH scale
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Atoms, Ions, and Molecules Are the Building
Blocks of Matter (3)

• Molecule
• Two or more atoms of the same or different
  elements held together by chemical bonds
• Chemical formula
• Number and each type atom or ion in a compound
• Symbol for each element and subscripts represent
  number of atoms or ions

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Ions Important to the Study of Environmental
Science
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Compounds Important to the Study of Environmental
Science
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Organic Compounds Are the Chemicals of Life

• Inorganic compounds
• all other compounds
• Organic compounds
• At least 2 carbon atoms combined with atoms of
  one or more elements CH4
• Hydrocarbons and chlorinated hydrocarbons
• Simple carbohydrates (simple sugars)
• Macromolecules complex organic molecules form
  when monomers link together
• Complex carbohydrates (polymers)
• Proteins (polymers)
• Nucleic acids (polymers)
• Lipids

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Loss of NO3- from a Deforested Watershed
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Matter Comes to Life through Genes, Chromosomes,
and Cells

• Cells fundamental units of life
• Genes sequences of nucleotides within the DNA
• Chromosomes composed of many genes

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Cells, Nuclei, Chromosomes, DNA, and Genes
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Matter Occurs in Various Physical Forms

• Differ in spacing and orderliness of atoms, ions,
  or molecules
• Solid
• Most compact, orderly arrangement
• Liquid
• Gas
• Least compact, orderly arrangement

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Some Forms of Matter Are More Useful than Others

• Matter Quality measure of how useful a form of
  matter is to humans as a resource, based on
  availability and concentration
• High-quality matter
• Highly concentrated, found near earths surface,
  great potential as resource
• Low-quality matter
• Not highly concentrated, found deep underground,
  little potential as resource

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Examples of Differences in Matter Quality
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Animation Subatomic particles
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Animation Carbon bonds
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Animation Ionic bonds
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Animation Atomic number, mass number
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2-3 How Can Matter Change?

• Concept 2-3 When matter undergoes a physical or
  chemical change, no atoms are created or
  destroyed (the law of conservation of matter).

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Matter Undergoes Physical, Chemical, and Nuclear
Changes

• Physical change
• Chemical change, chemical reaction
• Nuclear change
• Natural radioactive decay
• Radioisotopes unstable
• Nuclear fission
• Nuclear fusion

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Types of Nuclear Changes
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Fig. 2-7a, p. 41
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Radioactive decay
Alpha particle (helium-4 nucleus)
Radioactive isotope
Gamma rays
Beta particle (electron)
Fig. 2-7a, p. 41
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Fig. 2-7b, p. 41
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Nuclear fission
Uranium-235
Fission fragment
Energy
n
n
Neutron
n
n
Energy
Energy
n
n
Uranium-235
Fission fragment
Energy
Fig. 2-7b, p. 41
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Fig. 2-7c, p. 41
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Nuclear fusion
Reaction conditions
Fuel
Products
Proton
Neutron
Helium-4 nucleus
Hydrogen-2 (deuterium nucleus)
100 million C
Energy
Hydrogen-3 (tritium nucleus)
Neutron
Fig. 2-7c, p. 41
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Stepped Art
Fig. 2-7, p. 41
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We Cannot Create or Destroy Matter

• Law of conservation of matter
• Matter consumption
• Matter is converted from one form to another

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Animation Total energy remains constant
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Animation Half-life
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Animation Isotopes
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Animation Positron-emission tomography (PET)
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Video Nuclear energy
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2-4 What is Energy and How Can It Be Changed?

• Concept 2-4A When energy is converted from one
  form to another in a physical or chemical change,
  no energy is created or destroyed (first law of
  thermodynamics).
• Concept 2-4B Whenever energy is changed from one
  form to another, we end up with lower- quality or
  less usable energy than we started with (second
  law of thermodynamics).

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Energy Comes in Many Forms

• Kinetic energy
• Heat
• Transferred by radiation, conduction, or
  convection
• Electromagnetic radiation
• Potential energy
• Stored energy
• Can be changed into kinetic energy

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The Spectrum of Electromagnetic Radiation
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10
Energy emitted from sun (kcal/cm2/min)
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Visible
Infrared
Ultraviolet
0
2
0.25
1
2.5
3
Wavelength (micrometers)
Fig. 2-8, p. 42
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The Second Law of Thermodynamics in Living
Systems
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Mechanical energy (moving, thinking, living)
Chemical energy (food)
Chemical energy (photosynthesis)
Solar energy
Waste heat
Waste heat
Waste heat
Waste heat
Fig. 2-9, p. 43
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Some Types of Energy Are More Useful Than Others

• High-quality energy
• Low-quality energy

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Energy Changes Are Governed by Two Scientific Laws

• 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

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Active Figure Energy flow
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Active Figure Visible light
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Animation Martian doing mechanical work
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2-5 What Are Systems and How Do They Respond to
Change?

• Concept 2-5A Systems have inputs, flows, and
  outputs of matter and energy, and their behavior
  can be affected by feedback.
• Concept 2-5B Life, human systems, and the
  earths life support systems must conform to the
  law of conservation of matter and the two laws of
  thermodynamics.

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Systems Have Inputs, Flows, and Outputs

• System
• Inputs from the environment
• Flows, throughputs
• Outputs

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Inputs, Throughput, and Outputs of an Economic
System
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Throughputs
Outputs
Energy Inputs
Energy resources
Heat
Matter resources
Waste and pollution
Economy
Goods and services
Information
Fig. 2-10, p. 44
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Systems Respond to Change through Feedback Loops

• Positive feedback loop
• Negative, or corrective, feedback loop

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Positive Feedback Loop
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Negative Feedback Loop
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Time Delays Can Allow a System to Reach a Tipping
Point

• 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

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System Effects Can Be Amplified through Synergy

• Synergistic interaction, synergy
• Helpful
• Harmful
• E.g., Smoking and inhaling asbestos particles

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Human Activities Can Have Unintended Harmful
Results

• Deforested areas turning to desert
• Coral reefs dying
• Glaciers melting
• Sea levels rising

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Animation Economic types
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Animation Feedback control of temperature