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Chapter 2Chapter 2
Science, Systems, Science, Systems, Matter, and EnergyMatter, and Energy
Chapter Overview QuestionsChapter Overview Questions
What is science, and what do scientists do?What is science, and what do scientists do? What are major components and behaviors What are major components and behaviors
of complex systems?of complex systems? What are the basic forms of matter, and what What are the basic forms of matter, and what
makes matter useful as a resource?makes matter useful as a resource? What types of changes can matter undergo What types of changes can matter undergo
and what scientific law governs matter?and what scientific law governs matter?
Chapter Overview Questions (cont’d)Chapter Overview Questions (cont’d)
What are the major forms of energy, and What are the major forms of energy, and what makes energy useful as a resource?what makes energy useful as a resource?
What are two scientific laws governing What are two scientific laws governing changes of energy from one form to another?changes of energy from one form to another?
How are the scientific laws governing How are the scientific laws governing changes of matter and energy from one form changes of matter and energy from one form to another related to resource use, to another related to resource use, environmental degradation and environmental degradation and sustainability?sustainability?
Updates OnlineUpdates Online
The latest references for topics covered in this section can be found at 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 the book companion website. Log in to the book’s e-resources page at www.thomsonedu.com to access InfoTrac articles.www.thomsonedu.com to access InfoTrac articles.
InfoTrac: Underwater Microscope Finds Biological Treasures in InfoTrac: Underwater Microscope Finds Biological Treasures in Subtropical Ocean. Subtropical Ocean. Ascribe Higher Education News ServiceAscribe Higher Education News Service, June 26, , June 26, 2006.2006.
InfoTrac: In Bacterial Diversity, Amazon Is a 'Desert'; Desert Is an InfoTrac: In Bacterial Diversity, Amazon Is a 'Desert'; Desert Is an 'Amazon'. 'Amazon'. Ascribe Higher Education News ServiceAscribe Higher Education News Service, Jan 9, 2006., Jan 9, 2006.
InfoTrac: Making MGP wastes beneficial. Bob Paulson. InfoTrac: Making MGP wastes beneficial. Bob Paulson. Pollution Pollution EngineeringEngineering, June 2006 v38 i6 p20(5)., June 2006 v38 i6 p20(5).
NASA: Nitrogen CycleNASA: Nitrogen Cycle Environmental Literacy Council: Phosphorous CycleEnvironmental Literacy Council: Phosphorous Cycle National Sustainable Agriculture Information Service: Nutrient CyclesNational Sustainable Agriculture Information Service: Nutrient Cycles
Video: The Throw Away SocietyVideo: The Throw Away Society
This video clip is available in CNN Today This video clip is available in CNN Today Videos for Environmental Science, 2004, Videos for Environmental Science, 2004, Volume VII. Instructors, contact your local Volume VII. Instructors, contact your local sales representative to order this volume, sales representative to order this volume, while supplies last.while supplies last.
Core Case Study: Core Case Study: Environmental Lesson from Easter Environmental Lesson from Easter
IslandIsland Thriving societyThriving society
15,000 people by 1400.15,000 people by 1400. Used resources faster Used resources faster
than could be renewedthan could be renewed By 1600 only a few By 1600 only a few
trees remained.trees remained. Civilization collapsedCivilization collapsed
By 1722 only several By 1722 only several hundred people left.hundred people left.
Figure 2-1Figure 2-1
THE NATURE OF SCIENCETHE NATURE OF SCIENCE
What do scientists do?What do scientists do? Collect data.Collect data. Form hypotheses.Form hypotheses. Develop theories, Develop theories,
models and laws about models and laws about how nature works.how nature works.
Figure 2-2Figure 2-2
Fig. 2-2, p. 29
Well-tested andaccepted patterns
in data becomescientific laws
Interpret data
Ask a question
Do experimentsand collect data
Formulate hypothesisto explain data
Do more experimentsto test hypothesis
Revise hypothesisif necessary
Well-tested andaccepted
hypothesesbecome
scientific theories
Ask a question
Do experimentsand collect data
Formulate hypothesisto explain data
Do more experimentsto test hypothesis
Revise hypothesisif necessary
Well-tested andaccepted
hypothesesbecome
scientific theories
Interpret data
Well-tested andaccepted patternsIn data becomescientific laws
Fig. 2-3, p. 30
Stepped Art
Scientific Theories and Laws: The Scientific Theories and Laws: The Most Important Results of ScienceMost Important Results of Science
Scientific TheoryScientific Theory Widely tested and Widely tested and
accepted accepted hypothesis.hypothesis.
Scientific LawScientific Law What we find What we find
happening over and happening over and over again in over again in nature.nature.
Figure 2-3Figure 2-3
Fig. 2-3, p. 30
Research results
Scientific paper
Peer review byexperts in field
Paperrejected
Paper accepted
Paper published inscientific journal
Research evaluatedby scientific community
Testing HypothesesTesting Hypotheses
Scientists test hypotheses using controlled Scientists test hypotheses using controlled experiments and constructing mathematical experiments and constructing mathematical models.models. VariablesVariables or or factorsfactors influence natural processes influence natural processes Single-variable experiments involve a control and Single-variable experiments involve a control and
an experimental group.an experimental group. Most environmental phenomena are Most environmental phenomena are
multivariablemultivariable and are hard to control in an and are hard to control in an experiment.experiment.• Models are used to analyze interactions of variables.Models are used to analyze interactions of variables.
Scientific Reasoning and CreativityScientific Reasoning and Creativity
Inductive reasoningInductive reasoning Involves using specific observations and Involves using specific observations and
measurements to arrive at a general conclusion measurements to arrive at a general conclusion or hypothesis.or hypothesis.
Bottom-up reasoning going from specific to Bottom-up reasoning going from specific to general.general.
Deductive reasoningDeductive reasoning Uses logic to arrive at a specific conclusion.Uses logic to arrive at a specific conclusion. Top-down approach that goes from general to Top-down approach that goes from general to
specific.specific.
Frontier Science, Sound Science, and Frontier Science, Sound Science, and Junk ScienceJunk Science
Frontier science has not been widely tested Frontier science has not been widely tested (starting point of peer-review).(starting point of peer-review).
Sound science consists of data, theories and Sound science consists of data, theories and laws that are widely accepted by experts.laws that are widely accepted by experts.
Junk science is presented as sound science Junk science is presented as sound science without going through the rigors of peer-without going through the rigors of peer-review.review.
Limitations of Environmental ScienceLimitations of Environmental Science
Inadequate data and scientific understanding Inadequate data and scientific understanding can limit and make some results can limit and make some results controversial.controversial. Scientific testing is based on disproving rather Scientific testing is based on disproving rather
than proving a hypothesis.than proving a hypothesis.• Based on statistical probabilities.Based on statistical probabilities.
MODELS AND BEHAVIOR OF MODELS AND BEHAVIOR OF SYSTEMSSYSTEMS
Usefulness of modelsUsefulness of models Complex systems are predicted by developing a Complex systems are predicted by developing a
model of its inputs, throughputs (flows), and model of its inputs, throughputs (flows), and outputs of matter, energy and information.outputs of matter, energy and information.
Models are simplifications of “real-life”.Models are simplifications of “real-life”. Models can be used to predict Models can be used to predict if-thenif-then scenarios. scenarios.
Feedback Loops: Feedback Loops: How Systems Respond to ChangeHow Systems Respond to Change
Outputs of matter, energy, or information fed Outputs of matter, energy, or information fed back into a system can cause the system to back into a system can cause the system to do do moremore or or lessless of what it was doing. of what it was doing. Positive feedback loop causes a system to Positive feedback loop causes a system to
change further in the same direction (e.g. change further in the same direction (e.g. erosion)erosion)
Negative (corrective) feedback loop causes a Negative (corrective) feedback loop causes a system to change in the opposite direction (e.g. system to change in the opposite direction (e.g. seeking shade from sun to reduce stress).seeking shade from sun to reduce stress).
Feedback Loops: Feedback Loops:
Negative feedback can take so long that a Negative feedback can take so long that a system reaches a threshold and changes.system reaches a threshold and changes. Prolonged delays may prevent a negative Prolonged delays may prevent a negative
feedback loop from occurring.feedback loop from occurring. Processes and feedbacks in a system can Processes and feedbacks in a system can
(synergistically) interact to amplify the results.(synergistically) interact to amplify the results. E.g. smoking exacerbates the effect of asbestos E.g. smoking exacerbates the effect of asbestos
exposure on lung cancer.exposure on lung cancer.
TYPES AND STRUCTURE OF TYPES AND STRUCTURE OF MATTERMATTER
Elements and CompoundsElements and Compounds Matter exists in chemical forms as elements and Matter exists in chemical forms as elements and
compounds.compounds.• Elements (represented on the periodic table) are the Elements (represented on the periodic table) are the
distinctive building blocks of matter.distinctive building blocks of matter.• Compounds: two or more different elements held Compounds: two or more different elements held
together in fixed proportions by chemical bonds.together in fixed proportions by chemical bonds.
AtomsAtoms
Figure 2-4Figure 2-4
IonsIons
An ion is an atom or group of atoms with one An ion is an atom or group of atoms with one or more net positive or negative electrical or more net positive or negative electrical charges.charges.
The number of positive or negative charges The number of positive or negative charges on an ion is shown as a superscript after the on an ion is shown as a superscript after the symbol for an atom or group of atoms symbol for an atom or group of atoms Hydrogen ions (HHydrogen ions (H++), Hydroxide ions (OH), Hydroxide ions (OH--)) Sodium ions (NaSodium ions (Na++), Chloride ions (Cl), Chloride ions (Cl--))
The pH (potential of Hydrogen) is the The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of concentration of hydrogen ions in one liter of solution.solution.
Figure 2-5Figure 2-5
Compounds and Chemical FormulasCompounds and Chemical Formulas
Chemical formulas are shorthand ways to Chemical formulas are shorthand ways to show the atoms and ions in a chemical show the atoms and ions in a chemical compound. compound. Combining Hydrogen ions (HCombining Hydrogen ions (H++) and Hydroxide ) and Hydroxide
ions (OHions (OH--) makes the compound H) makes the compound H22O O
(dihydrogen oxide, a.k.a. water).(dihydrogen oxide, a.k.a. water). Combining Sodium ions (NaCombining Sodium ions (Na++) and Chloride ions ) and Chloride ions
(Cl(Cl--) makes the compound NaCl (sodium chloride ) makes the compound NaCl (sodium chloride a.k.a. salt).a.k.a. salt).
Organic Compounds: Carbon RulesOrganic Compounds: Carbon Rules
Organic compounds contain carbon atoms Organic compounds contain carbon atoms combined with one another and with various combined with one another and with various other atoms such as Hother atoms such as H++, N, N++, or Cl, or Cl--..
Contain at least two carbon atoms combined Contain at least two carbon atoms combined with each other and with atoms.with each other and with atoms. Methane (CHMethane (CH44) is the only exception.) is the only exception. All other compounds are All other compounds are inorganicinorganic..
Organic Compounds: Carbon RulesOrganic Compounds: Carbon Rules
HydrocarbonsHydrocarbons: compounds of carbon and : compounds of carbon and hydrogen atoms (e.g. methane (CHhydrogen atoms (e.g. methane (CH44)).)).
Chlorinated hydrocarbonsChlorinated hydrocarbons: compounds of : compounds of carbon, hydrogen, and chlorine atoms (e.g. carbon, hydrogen, and chlorine atoms (e.g. DDT (CDDT (C1414HH99CCl5l5)).)).
Simple carbohydratesSimple carbohydrates: certain types of : certain types of compounds of carbon, hydrogen, and oxygen compounds of carbon, hydrogen, and oxygen (e.g. glucose (C(e.g. glucose (C66HH1212OO66)).)).
Cells: The Fundamental Units of LifeCells: The Fundamental Units of Life
Cells are the basic Cells are the basic structural and structural and functional units of all functional units of all forms of life.forms of life. Prokaryotic cells Prokaryotic cells
(bacteria) lack a distinct (bacteria) lack a distinct nucleus.nucleus.
Eukaryotic cells (plants Eukaryotic cells (plants and animals) have a and animals) have a distinct nucleus.distinct nucleus.
Figure 2-6Figure 2-6
Fig. 2-6a, p. 37
(a) Prokaryotic Cell
Protein constructionand energy conversionoccur without specializedinternal structures
Cell membrane(transport ofraw materials and finished products)
DNA(information storage, no nucleus)
Fig. 2-6b, p. 37
Protein construction
(b) Eukaryotic Cell
Cell membrane(transport of rawmaterials andfinished products)Packaging
Energy conversion
Nucleus (informationstorage)
Macromolecules, DNA, Genes and Macromolecules, DNA, Genes and ChromosomesChromosomes Large, complex organic Large, complex organic
molecules (macromolecules) molecules (macromolecules) make up the basic molecular make up the basic molecular units found in living units found in living organisms.organisms. Complex carbohydratesComplex carbohydrates ProteinsProteins Nucleic acidsNucleic acids LipidsLipids
Figure 2-7Figure 2-7
Fig. 2-7, p. 38
The genes in each cell are coded by sequences of nucleotides in their DNA molecules.
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 proteins—the building blocks of life.
Fig. 2-7, p. 38
A human body contains trillionsof cells, each with an identicalset of genes.
There is a nucleus inside eachhuman cell (except red blood cells).
Each cell nucleus has an identicalset of chromosomes, which arefound in pairs.
A specific pair of chromosomescontains one chromosome fromeach parent.
Each chromosome contains a longDNA molecule in the form of a coileddouble helix.
Genes are segments of DNA onchromosomes that contain instructionsto make proteins—the building blocksof life.
The genes in each cell are codedby sequences of nucleotides intheir DNA molecules.
Stepped Art
States of MatterStates of Matter
The atoms, ions, and molecules that make up The atoms, ions, and molecules that make up matter are found in three physical states:matter are found in three physical states: solid, liquid, gaseous.solid, liquid, gaseous.
A fourth state, plasma, is a high energy A fourth state, plasma, is a high energy mixture of positively charged ions and mixture of positively charged ions and negatively charged electrons.negatively charged electrons. The sun and stars consist mostly of plasma.The sun and stars consist mostly of plasma. Scientists have made artificial plasma (used in Scientists have made artificial plasma (used in
TV screens, gas discharge lasers, florescent TV screens, gas discharge lasers, florescent light).light).
Matter QualityMatter Quality
Matter can be classified Matter can be classified as having high or low as having high or low quality depending on quality depending on how useful it is to us as how useful it is to us as a resource.a resource. High quality matter is High quality matter is
concentrated and easily concentrated and easily extracted.extracted.
low quality matter is more low quality matter is more widely dispersed and widely dispersed and more difficult to extract.more difficult to extract.
Figure 2-8Figure 2-8
Fig. 2-8, p. 39
High Quality Low Quality
Salt
Solid Gas
Coal Coal-fired power plant emissions
GasolineAutomobile emissions
Solution of salt in water
Aluminum oreAluminum can
CHANGES IN MATTERCHANGES IN MATTER Matter can change from one physical form to Matter can change from one physical form to
another or change its chemical composition.another or change its chemical composition. When a physical or chemical change occurs, no When a physical or chemical change occurs, no
atoms are created or destroyed.atoms are created or destroyed.• Law of conservation of matter.Law of conservation of matter.
Physical change maintains original chemical Physical change maintains original chemical composition.composition.
Chemical change involves a chemical reaction Chemical change involves a chemical reaction which changes the arrangement of the elements which changes the arrangement of the elements or compounds involved.or compounds involved.• Chemical equations are used to represent the Chemical equations are used to represent the
reaction.reaction.
Chemical ChangeChemical Change
Energy is given off during the reaction as a product.Energy is given off during the reaction as a product.
p. 39
Reactant(s) Product(s)
carbon + oxygen carbon dioxide + energy
C + O2 CO2 energy+
energy+
black solid colorless gas colorless gas
+
Types of PollutantsTypes of Pollutants
Factors that determine the severity of a Factors that determine the severity of a pollutant’s effects: pollutant’s effects: chemical naturechemical nature, , concentrationconcentration, and , and persistencepersistence..
Pollutants are classified based on their Pollutants are classified based on their persistence:persistence: Degradable pollutantsDegradable pollutants Biodegradable pollutantsBiodegradable pollutants Slowly degradable pollutantsSlowly degradable pollutants Nondegradable pollutantsNondegradable pollutants
Nuclear Changes: Radioactive DecayNuclear Changes: Radioactive Decay
Natural radioactive decay: unstable isotopes Natural radioactive decay: unstable isotopes spontaneously emit fast moving chunks of spontaneously emit fast moving chunks of matter (matter (alphaalpha oror beta particlesbeta particles), high-energy ), high-energy radiation (radiation (gamma raysgamma rays), or both at a fixed ), or both at a fixed rate.rate. Radiation is commonly used in energy production Radiation is commonly used in energy production
and medical applications.and medical applications. The rate of decay is expressed as a The rate of decay is expressed as a half-lifehalf-life (the (the
time needed for one-half of the nuclei to decay to time needed for one-half of the nuclei to decay to form a different isotope).form a different isotope).
Nuclear Changes: FissionNuclear Changes: Fission
Nuclear fission: Nuclear fission: nuclei of certain nuclei of certain isotopes with large isotopes with large mass numbers are mass numbers are split apart into split apart into lighter nuclei when lighter nuclei when struck by neutrons.struck by neutrons.
Figure 2-9Figure 2-9
Fig. 2-9, p. 41
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Neutron
FissionFragment
FissionFragment
Energy
EnergyEnergy
Energy
n
n
n
n
n
n
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235 Fig. 2-6, p. 28
Neutron
Uranium-235
Energy
Fissionfragment
Fissionfragment
n
n
n
n
n
n
Energy
Energy
Energy
Stepped Art
Nuclear Changes: FusionNuclear Changes: Fusion
Nuclear fusion: two isotopes of light elements Nuclear fusion: two isotopes of light elements are forced together at extremely high are forced together at extremely high temperatures until they fuse to form a heavier temperatures until they fuse to form a heavier nucleus.nucleus.
Figure 2-10Figure 2-10
Fig. 2-10, p. 42
Neutron
+
Hydrogen-2(deuterium nucleus)
Hydrogen-3(tritium nucleus)
+
Proton Neutron
100million °C
Energy
+
Helium-4 nucleus
ProductsReaction
ConditionsFuel
+
ENERGYENERGY
Energy is the ability to do work and transfer Energy is the ability to do work and transfer heat.heat. Kinetic energy – energy in motionKinetic energy – energy in motion
• heat, electromagnetic radiationheat, electromagnetic radiation Potential energy – stored for possible usePotential energy – stored for possible use
• batteries, glucose moleculesbatteries, glucose molecules
Electromagnetic SpectrumElectromagnetic Spectrum
Many different forms of electromagnetic Many different forms of electromagnetic radiation exist, each having a different radiation exist, each having a different wavelength and energy content.wavelength and energy content.
Figure 2-11Figure 2-11
Fig. 2-11, p. 43
Sun
Nonionizing radiationIonizing radiation
High energy, shortWavelength
Wavelength in meters(not to scale)
Low energy, longWavelength
Cosmicrays
GammaRays
X raysFar
infrared waves
Nearultra-violetwaves
VisibleWaves
Nearinfraredwaves
Farultra-violetwaves
Micro-waves
TVwaves
RadioWaves
Electromagnetic SpectrumElectromagnetic Spectrum
Organisms vary Organisms vary in their ability to in their ability to sense different sense different parts of the parts of the spectrum.spectrum.
Figure 2-12Figure 2-12
Fig. 2-12, p. 43
En
erg
y em
itte
d f
rom
su
n (
kcal
/cm
2 /m
in)
Wavelength (micrometers)
Ult
ravi
ole
t
Visible
Infrared
Fig. 2-13, p. 44
Low-temperature heat (100°C or less) for space heating
Moderate-temperature heat (100–1,000°C) for industrial processes, cooking, producing
steam, electricity, and hot water
Very high-temperature heat (greater than 2,500°C) for industrial processes and producing electricity to run electrical devices (lights, motors)
Mechanical motion to move vehicles and other things) High-temperature heat (1,000–2,500°C) for industrial processes and producing electricity
Dispersed geothermal energyLow-temperature heat (100°C or lower)
Normal sunlightModerate-velocity windHigh-velocity water flowConcentrated geothermal energyModerate-temperature heat
(100–1,000°C)Wood and crop wastes
High-temperature heat (1,000–2,500°C)Hydrogen gasNatural gasGasolineCoalFood
ElectricityVery high temperature heat (greater than 2,500°C)Nuclear fission (uranium)Nuclear fusion (deuterium)Concentrated sunlightHigh-velocity wind
Source of Energy RelativeEnergy Quality
(usefulness)
Energy Tasks
ENERGY LAWS: TWO RULES WE ENERGY LAWS: TWO RULES WE CANNOT BREAKCANNOT BREAK
The first law of thermodynamics: we cannot The first law of thermodynamics: we cannot create or destroy energy.create or destroy energy. We can change energy from one form to another.We can change energy from one form to another.
The second law of thermodynamics: energy The second law of thermodynamics: energy quality always decreases.quality always decreases. When energy changes from one form to another, When energy changes from one form to another,
it is always degraded to a more dispersed form.it is always degraded to a more dispersed form. Energy efficiency is a measure of how much Energy efficiency is a measure of how much
useful work is accomplished before it changes to useful work is accomplished before it changes to its next form.its next form.
Fig. 2-14, p. 45
Chemicalenergy(food)
Solarenergy
WasteHeat
WasteHeat
WasteHeat
WasteHeat
Mechanicalenergy
(moving,thinking,
living)
Chemical energy
(photosynthesis)
SUSTAINABILITY AND MATTER SUSTAINABILITY AND MATTER AND ENERGY LAWSAND ENERGY LAWS
Unsustainable High-Throughput Economies: Unsustainable High-Throughput Economies: Working in Straight LinesWorking in Straight Lines Converts resources to goods in a manner that Converts resources to goods in a manner that
promotes waste and pollution.promotes waste and pollution.
Figure 2-15Figure 2-15
Fig. 2-15, p. 46
High-quality energy
Matter
Unsustainablehigh-waste
economy
SystemThroughputs
Inputs(from environment)
Outputs(into environment)
Low-quality energy (heat)
Waste and pollution
Sustainable Low-Throughput Sustainable Low-Throughput Economies: Learning from NatureEconomies: Learning from Nature
Matter-Recycling-and-Reuse Economies: Matter-Recycling-and-Reuse Economies: Working in CirclesWorking in Circles Mimics nature by recycling and reusing, thus Mimics nature by recycling and reusing, thus
reducing pollutants and waste.reducing pollutants and waste. It is not sustainable for growing populations.It is not sustainable for growing populations.
Fig. 2-16, p. 47
Recycleand
reuse
Low-quality Energy(heat)
Waste and
pollution
Pollutioncontrol
Sustainable low-waste economy
Waste and
pollution
Matter Feedback
Energy Feedback
Inputs (from environment)
Energyconservation
Matter
Energy
SystemThroughputs
Outputs(into environment)