Science, Systems, Matter, and Energy

1
Chapter 2

• Science, Systems, Matter, and Energy

2
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
3
Video Easter Island
Videos/easter_island.html

• From ABC News, Environmental Science in the
  Headlines, 2005 DVD.

4
Video The Throw Away Society

• Throw Away Society
• Garbage Crisis In Italy

5
THE NATURE OF SCIENCE

• What do scientists do?
• Collect data.
• Form hypotheses.
• Develop theories, models and laws about how
  nature works.

Figure 2-2
6
Scientific Theories and Laws The Most Important
Results of Science

• Scientific Theory
• Widely tested and accepted hypothesis.
• Scientific Law
• What we find happening over and over again in
  nature.

Figure 2-3
7
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.

8
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.

9
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.

10
Limitations of Environmental Science

• Inadequate data and scientific understanding can
  limit and make some results controversial.
• Scientific testing is based on disproving rather
  than proving a hypothesis.
• Based on statistical probabilities.

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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.

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Feedback Loops How Systems Respond to Change

• Outputs of matter, energy, or information fed
  back into a system can cause the system to do
  more or less of what it was doing.
• Positive feedback loop causes a system to change
  further in the same direction (e.g. erosion)
• Negative (corrective) feedback loop causes a
  system to change in the opposite direction (e.g.
  seeking shade from sun to reduce stress).

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Animation Feedback Control of Temperature
Animations/dog_homeostasis.html
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Feedback Loops

• Negative feedback can take so long that a system
  reaches a threshold and changes.
• Prolonged delays may prevent a negative feedback
  loop from occurring.
• Processes and feedbacks in a system can
  (synergistically) interact to amplify the
  results.
• E.g. smoking exacerbates the effect of asbestos
  exposure on lung cancer.

15
TYPES AND STRUCTURE OF MATTER

• Elements and Compounds
• Matter exists in chemical forms as elements and
  compounds.
• 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.

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Atoms
Figure 2-4
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Animation Subatomic Particles
Animations/atomic_particles.html
18
Animation Atomic Number, Mass Number
Animations/mass_number.html
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Ions

• An ion is an atom or group of atoms with one or
  more net positive or negative electrical charges.
• The number of positive or negative charges on an
  ion is shown as a superscript after the symbol
  for an atom or group of atoms
• Hydrogen ions (H), Hydroxide ions (OH-)
• Sodium ions (Na), Chloride ions (Cl-)

20
Animation Ionic Bonds
Animations/ionic_bond.html
21

• The pH (potential of Hydrogen) is the
  concentration of hydrogen ions in one liter of
  solution.

Figure 2-5
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Animation pH Scale
Animations/ph_meter.html
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Compounds and Chemical Formulas

• Chemical formulas are shorthand ways to show the
  atoms and ions in a chemical compound.
• Combining Hydrogen ions (H) and Hydroxide ions
  (OH-) makes the compound H2O (dihydrogen oxide,
  a.k.a. water).
• Combining Sodium ions (Na) and Chloride ions
  (Cl-) makes the compound NaCl (sodium chloride
  a.k.a. salt).

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Organic Compounds Carbon Rules

• 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.

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Animation Carbon Bonds
Animations/carbon_bonding.html
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Organic Compounds Carbon Rules

• Hydrocarbons compounds of carbon and hydrogen
  atoms (e.g. methane (CH4)).
• Chlorinated hydrocarbons compounds of carbon,
  hydrogen, and chlorine atoms (e.g. DDT
  (C14H9Cl5)).
• Simple carbohydrates certain types of compounds
  of carbon, hydrogen, and oxygen (e.g. glucose
  (C6H12O6)).

27
Cells The Fundamental Units of Life

• Cells are the basic structural and functional
  units of all forms of life.
• Prokaryotic cells (bacteria) lack a distinct
  nucleus.
• Eukaryotic cells (plants and animals) have a
  distinct nucleus.

Figure 2-6
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Animation Prokaryotic and Eukaryotic Cells
Animations/cell_features_v2.html
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Macromolecules, DNA, Genes and Chromosomes

• Large, complex organic molecules (macromolecules)
  make up the basic molecular units found in living
  organisms.
• Complex carbohydrates
• Proteins
• Nucleic acids
• Lipids

Figure 2-7
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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).

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Matter Quality

• 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
32
CHANGES IN MATTER

• Matter can change from one physical form to
  another or change its chemical composition.
• When a physical or chemical change occurs, no
  atoms are created or destroyed.
• Law of conservation of matter.
• Physical change maintains original chemical
  composition.
• Chemical change involves a chemical reaction
  which changes the arrangement of the elements or
  compounds involved.
• Chemical equations are used to represent the
  reaction.

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Chemical Change

• Energy is given off during the reaction as a
  product.

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Types of Pollutants

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

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Nuclear Changes Radioactive Decay

• Natural radioactive decay unstable isotopes
  spontaneously emit fast moving chunks of matter
  (alpha or beta 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).

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Animation Positron-Emission Tomography
Animations/pet_scan.html
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Animation Half-Life
Animations/half_life.html
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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
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Stepped Art
Fig. 2-6, p. 28
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Video Isotopes
Videos/isotopes.html
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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
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Video Nuclear Energy
Videos/nuclear_energy.html

• From ABC News, Environmental Science in the
  Headlines, 2005 DVD.

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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

Animations/martian_working.html
44
Electromagnetic Spectrum

• Many different forms of electromagnetic radiation
  exist, each having a different wavelength and
  energy content.

Figure 2-11
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Electromagnetic Spectrum

• Organisms vary in their ability to sense
  different parts of the spectrum.

Figure 2-12
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Animation Visible Light
Animations/light_wavelength.html
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Relative Energy Quality (usefulness)
Source of Energy
Energy Tasks
Electricity Very high temperature heat (greater
than 2,500C) Nuclear fission (uranium) Nuclear
fusion (deuterium) Concentrated
sunlight High-velocity wind
Very high-temperature heat (greater than 2,500C)
for industrial processes and producing
electricity to run electrical devices (lights,
motors)
High-temperature heat (1,0002,500C) Hydroge
n gas Natural gas Gasoline Coal Food
Mechanical motion to move vehicles and other
things) High-temperature heat (1,0002,500C)
for industrial processes and producing
electricity
Normal sunlight Moderate-velocity
wind High-velocity water flow Concentrated
geothermal energy Moderate-temperature
heat (1001,000C) Wood and crop wastes
Moderate-temperature heat (1001,000C) for
industrial processes, cooking, producing steam,
electricity, and hot water
Dispersed geothermal energy Low-temperature heat
(100C or lower)
Low-temperature heat (100C or less) for
space heating
Fig. 2-13, p. 44
48
ENERGY LAWS TWO RULES WE CANNOT BREAK

• 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.

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Animation Total Energy Remains Constant
Animations/energy_constant.html
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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
51
Animation Energy Flow
Animations/energy_flow.html
52
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
53
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.

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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
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Animation Economic Types
Animations/hi_low-throughput.html