Science, Systems, Matter, and Energy

1
Chapter 2

• Science, Systems, Matter, and Energy

2
Chapter Overview Questions

• What is science, and what do scientists do?
• What are major components and behaviors of
  complex systems?
• What are the basic forms of matter, and what
  makes matter useful as a resource?
• What types of changes can matter undergo and what
  scientific law governs matter?

3
Chapter Overview Questions (contd)

• What are the major forms of energy, and what
  makes energy useful as a resource?
• What are two scientific laws governing changes of
  energy from one form to another?
• How are the scientific laws governing changes of
  matter and energy from one form to another
  related to resource use, environmental
  degradation and sustainability?

4
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
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
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 scienti
fic theories
Fig. 2-2, p. 29
7
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
8
Research results
Scientific paper
Peer review by experts in field
Paper rejected
Paper accepted
Paper published in scientific journal
Research evaluated by scientific community
Fig. 2-3, p. 30
9
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.

10
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.

11
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.

12
Junk science

• 4 ways to recognize junk science
• What data supports the propsed?
• Have these been verified
• Does the explanation account for all
  observations? Are there alternative explanations?
• Have conclusions been verified by peer review?
• Are conclusions accepted by others in the field?

13
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.

14
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.

15
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).

16
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.

17
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.

18
Atoms
Figure 2-4
19
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

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

Figure 2-5
21
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).

22
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.

23
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)).

24
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
25
(a) Prokaryotic Cell
DNA(information storage, no nucleus)
Cell membrane (transport of raw materials and
finished products)
Protein construction and energy conversion occur
without specialized internal structures
Fig. 2-6a, p. 37
26
(b) Eukaryotic Cell
Energy conversion
Nucleus (information storage)
Protein construction
Cell membrane (transport of raw materials
and finished products)
Packaging
Fig. 2-6b, p. 37
27
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
28
A human body contains trillions of cells, each
with an identical set of genes.
There is a nucleus inside each human cell (except
red blood cells).
Each cell nucleus has an identical set of
chromosomes, which are found in pairs.
A specific pair of chromosomes contains one
chromosome from each parent.
Each chromosome contains a long DNA molecule in
the form of a coiled double helix.
Genes are segments of DNA on chromosomes that
contain instructions to make proteinsthe
building blocks of life.
The genes in each cell are coded by sequences of
nucleotides in their DNA molecules.
Fig. 2-7, p. 38
29
A human body contains trillions of cells, each
with an identical set of genes.
There is a nucleus inside each human cell (except
red blood cells).
Each cell nucleus has an identical set of
chromosomes, which are found in pairs.
A specific pair of chromosomes contains one
chromosome from each parent.
Each chromosome contains a long DNA molecule in
the form of a coiled double helix.
Genes are segments of DNA on chromosomes that
contain instructions to make proteinsthe
building blocks of life.
The genes in each cell are coded by sequences of
nucleotides in their DNA molecules.
Stepped Art
Fig. 2-7, p. 38
30
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).

31
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
High Quality
Low Quality
Solid
Gas
Solution of salt in water
Salt
Coal
Coal-fired power plant emissions
Gasoline
Automobile emissions
Aluminum can
Aluminum ore
Fig. 2-8, p. 39
33
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.

34
Chemical Change

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

35
Reactant(s)
Product(s)
energy
carbon dioxide
carbon

oxygen

energy

O2
C
CO2

energy


black solid
colorless gas
colorless gas
p. 39
36
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

37
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).

38
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
39
Uranium-235
Uranium-235
Uranium-235
Energy
Fission Fragment
Uranium-235
n
n
Neutron
n
n
Uranium-235
Energy
Energy
n
n
Uranium-235
Fission Fragment
Uranium-235
Energy
Uranium-235
Uranium-235
Uranium-235
Fig. 2-9, p. 41
40
Stepped Art
Fig. 2-6, p. 28
41
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
42
Reaction Conditions
Products
Fuel
Proton
Neutron
Energy
Hydrogen-2 (deuterium nucleus)

100 million C

Helium-4 nucleus


Hydrogen-3 (tritium nucleus)
Neutron
Fig. 2-10, p. 42
43
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

44
Electromagnetic Spectrum

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

Figure 2-11
45
Sun
Nonionizing radiation
Ionizing radiation
Near infrared waves
Far infrared waves
Near ultra- violet waves
Far ultra- violet waves
Cosmic rays
Gamma Rays
Visible Waves
TV waves
Radio Waves
X rays
Micro- waves
High energy, short Wavelength
Wavelength in meters (not to scale)
Low energy, long Wavelength
Fig. 2-11, p. 43
46
Electromagnetic Spectrum

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

Figure 2-12
47
Energy emitted from sun (kcal/cm2/min)
Visible
Infrared
Ultraviolet
Wavelength (micrometers)
Fig. 2-12, p. 43
48
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
49
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.

50
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
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
52
System Throughputs
Inputs (from environment)
Outputs (into environment)
Unsustainable high-waste economy
High-quality energy
Low-quality energy (heat)
Matter
Waste and pollution
Fig. 2-15, p. 46
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.

54
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