Chapter 2
Science, Systems,
Matter, and Energy
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?
Chapter Overview Questions (cont’d)
 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?
Updates Online
The latest references for topics covered in this section can be found at
the book companion website. Log in to the book’s e-resources page at
www.thomsonedu.com to access InfoTrac articles.






InfoTrac: Underwater Microscope Finds Biological Treasures in
Subtropical Ocean. Ascribe Higher Education News Service, June 26,
2006.
InfoTrac: In Bacterial Diversity, Amazon Is a 'Desert'; Desert Is an
'Amazon'. Ascribe Higher Education News Service, Jan 9, 2006.
InfoTrac: Making MGP wastes beneficial. Bob Paulson. Pollution
Engineering, June 2006 v38 i6 p20(5).
NASA: Nitrogen Cycle
Environmental Literacy Council: Phosphorous Cycle
National Sustainable Agriculture Information Service: Nutrient Cycles
Video: The Throw Away Society
 This
video clip is available in CNN Today
Videos for Environmental Science, 2004,
Volume VII. Instructors, contact your local
sales representative to order this volume,
while supplies last.
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
THE NATURE OF SCIENCE
 What




do scientists do?
Collect data.
Scientist Answer
Questions & Solve
Problems
Form hypotheses.
Develop theories,
models and laws about
how nature works.
Figure 2-2
Scientific Theories and Laws: The
Most Important Results of Science

Scientific Theory



Widely tested and
accepted hypothesis.
Has evidence that
supports it.
Scientific Law


What we find
happening over and
over again in nature.
Fact / Always True
Figure 2-3
Important Features of Scientific Process
 Skepticism

Scientists tend to be highly skepticle of new data
until they can be verified
 Peer

Review
Scientist working in the same field examine &
criticize work of colleges either through Journals
or Conferences.
 Reproducibility

Experiments/Data should be reporducable by
other scientists.
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.
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.
Controlled Experiments
 Controlled
experiments limit the number of
variables to testing primarily one variable.
 Control group lacks variable (independent
variable) and experimental group has
variable.
Q- Why are controlled experiments not
effective when analyzing environmental
phenomena?
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 peerreview.
Limitations of Environmental Science
 Inadequate
data and scientific understanding
can limit and make some results
controversial.

Scientists will rarely say 100%!
 Note-
Realize that opportunists can take
advantage of morally correct scientists.
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.
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).
Types of Pollutants
 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
Synergistic Interaction
 A synergisitc
interaction occurs when tow or
more processes interact so that the combined
effect is greater than the sum of their
individual effects when separate.
 Smokers- 10x the risk of lung cancer
 Asbestos exposure- 5x the risk of lung
cancer
 Exposure to Both- 50x
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).
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
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
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
Electromagnetic Spectrum
 Many
different forms of electromagnetic
radiation exist, each having a different
wavelength and energy content.
Figure 2-11
Electromagnetic Spectrum
 Organisms
vary
in their ability to
sense different
parts of the
spectrum.
Figure 2-12
Source of Energy
Electricity
Very high temperature heat
(greater than 2,500°C)
Nuclear fission (uranium)
Nuclear fusion (deuterium)
Concentrated sunlight
High-velocity wind
Relative
Energy Tasks (Diagram on pg 44)
Energy Quality
(usefulness)
Very high-temperature heat
(greater than 2,500°C) for
industrial processes and
producing electricity to run
electrical devices (lights,
motors)
High-temperature heat
(1,000–2,500°C)
Hydrogen gas
Natural gas
Gasoline
Coal
Food
Mechanical motion to move
vehicles and other things)
High-temperature heat
(1,000–2,500°C) for
industrial processes and
producing electricity
Normal sunlight
Moderate-velocity wind
High-velocity water flow
Concentrated geothermal energy
Moderate-temperature heat
(100–1,000°C)
Wood and crop wastes
Moderate-temperature heat
(100–1,000°C) for
industrial processes, cooking,
producing
steam, electricity, and
hot water
Dispersed geothermal energy
Low-temperature heat
(100°C or lower)
Low-temperature heat
(100°C or less) for
space heating
Fig. 2-13, p. 44
ENERGY LAWS: TWO RULES WE
CANNOT BREAK

The first law of thermodynamics: we cannot create
or destroy energy.


Environmentally- We cannot get something for nothing in
terms of energy quantity..
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.
When energy changes form one form to another- there is
a decrease in energy quality- so less work can be
accomplished.
Chemical
energy
(photosynthesis)
Solar
energy
Waste
Heat
Mechanical
energy
(moving,
thinking,
living)
Chemical
energy
(food)
Waste
Heat
Waste
Heat
Waste
Heat
Fig. 2-14, p. 45
The Thermo Lesson- the best way to get
more energy is to stop wasting almost half
of the energy we use!
 Methods






of Reducing Energy Waste:
Driving gas efficient cars
Living in well insulated houses
Energy efficient lights
Energy efficient heating & cooling
Energy efficient appliances
Running appliances from sun (renewable energy)
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
System
Throughputs
Inputs
(from environment)
High-quality energy
Matter
Outputs
(into environment)
Unsustainable
high-waste
economy
Low-quality energy (heat)
Waste and pollution
Fig. 2-15, p. 46
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.
Inputs
(from environment)
Energy
Matter
System
Throughputs
Outputs
(into environment)
Energy
conservation
Waste
and
pollution
Low-quality
Energy
(heat)
Sustainable
low-waste
economy
Pollution
control
Matter
Feedback
Waste
and
pollution
Recycle
and
reuse
Energy Feedback
Fig. 2-16, p. 47
Sustainable Low Throughput EconomicsLearning from Nature!
 We
can live more sustainably by reducing the
throughput of matter and energy in our
economies, not wasting matter and energy
resources, recycling and reusing most of the
matter resources we use, and stabilizing the
size of our population.