Chapter 2Chapter 2 Science, Systems, Science, Systems, Matter, and EnergyMatter, and Energy

Matter

“High-Q” Energy

“Low-Q” 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 What are major componentscomponents and and behaviorsbehaviors

of of complex systemscomplex systems?? What are the What are the basic formsbasic forms of matter, and what of matter, and what

makes makes matter usefulmatter useful as a resource? as a resource? What types of What types of changeschanges can matter undergo 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 What are the major forms of energyforms of energy, and , and what makes what makes energy usefulenergy useful as a resource? as a resource?

What are What are two scientifictwo scientific laws governing laws governing changes of energy changes of energy from one form to another?from one form to another?

How are the scientific laws governing How are the scientific laws governing changes of matter and energychanges of matter and energy from one form from one form to another related to to another related to resource useresource use, , environmental degradationenvironmental degradation and and sustainabilitysustainability??

THE NATURE OF SCIENCETHE NATURE OF SCIENCE Purpose of science:Purpose of science:

Discover order in the Discover order in the natural world and make natural world and make predictions about what is predictions about what is likely to happen in the likely to happen in the futurefuture

What do scientists do?What do scientists do? Collect data.Collect data. Form hypotheses.Form hypotheses. Develop theories, models Develop theories, models

and laws about how nature and laws about how nature works.works.

nextnext

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.

Atomic TheoryAtomic Theory

Scientific LawScientific Law What we find What we find

happening over and happening over and over again in over again in nature.nature.

Gravitational Gravitational ConstantConstant

next

“Peer Review”

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

Peer Review Process…

…Brutal!

Testing HypothesesTesting Hypotheses

Scientists test hypotheses using Scientists test hypotheses using controlled controlled experimentsexperiments and constructing and constructing mathematical 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 multivariatemultivariate and are hard to control in an and are hard to control in an experiment.experiment.• ModelsModels are used to analyze interactions of variables. are used to analyze interactions of variables.

A Controlled Experiment:The Effects A Controlled Experiment:The Effects of Deforestation on the Loss of Water of Deforestation on the Loss of Water

and Soil Nutrients (p.28)and Soil Nutrients (p.28)

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 reasoningBottom-up reasoning going from specific to 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 approachTop-down approach that goes from general to that goes from general to

specific.specific.

Frontier Science, Sound Science, and Frontier Science, Sound Science, and Junk ScienceJunk Science

Reliable science a.k.a. consensus science Reliable science a.k.a. consensus science a.k.a. sound sciencea.k.a. sound science consists of data, consists of data, theories and laws that are widely accepted by theories and laws that are widely accepted by experts.experts.

Tentative science a.k.a. frontier scienceTentative science a.k.a. frontier science has has not been widely tested (starting point of peer-not been widely tested (starting point of peer-review).review).

Unreliable science a.k.a. junk scienceUnreliable science a.k.a. junk science is is presented as sound science without going presented as sound science without going through the rigors of peer-review.through the rigors of peer-review.

Paradigm ShiftParadigm Shift

Paradigm Shift-Paradigm Shift- a complete change in a complete change in worldview as a result of new informationworldview as a result of new information

ExEx Earth-centered to sun-centered view of Earth-centered to sun-centered view of solar systemsolar system

Limitations of Environmental ScienceLimitations of Environmental Science

Inadequate data and scientific understandingInadequate 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 model of Complex systems are predicted by developing a model of

its inputs, throughputs (flows), and outputs of matter, its inputs, throughputs (flows), and outputs of matter, energy and information.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.

Poorly defined models of a system result in unreliable Poorly defined models of a system result in unreliable results…models are continuously tested against new real results…models are continuously tested against new real data data

Feedback Loops: Feedback Loops: How Systems Respond to ChangeHow Systems Respond to Change

Outputs of matter, energy, or information Outputs of matter, energy, or information fed fed backback into a system can cause the system to 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 loopPositive feedback loop (a.k.a.reinforcing loop) (a.k.a.reinforcing loop)

causes a system to change further in the same causes a system to change further in the same direction (e.g. population, fighting, erosion, direction (e.g. population, fighting, erosion, greed)greed)

Negative feedback loopNegative feedback loop (a.k.a. balancing loop) (a.k.a. balancing loop) causes a system to change in the opposite causes a system to change in the opposite direction (e.g. seeking shade from sun to reduce direction (e.g. seeking shade from sun to reduce stress, hunger & eating, body temp regulation).stress, hunger & eating, body temp regulation).

Feedback Loops: Feedback Loops: How Systems Respond to ChangeHow Systems Respond to Change

Practice Positive Practice Positive Practice NegativePractice Negative

Feedback LoopFeedback Loop Feedback LoopFeedback Loop

••brother & sister yellingbrother & sister yelling •• hunger & eating hunger & eating

Draw each loop and determine if it represents positive Draw each loop and determine if it represents positive or negative feedback:or negative feedback:

• • thirst & drinkingthirst & drinking

••pine trees & seedspine trees & seeds

••body temperature (hot day) & sweatingbody temperature (hot day) & sweating

••bank account & interest paymentbank account & interest payment

••angry thought & angry feelingsangry thought & angry feelings

Feedback Loops: Feedback Loops: Threshold Behavior-Threshold Behavior- Negative feedback can Negative feedback can

take so long that a system reaches a take so long that a system reaches a tipping tipping pointpoint and drastically changes. and drastically changes. E.g. tipping over in a chair; the recent economic E.g. tipping over in a chair; the recent economic

troubles; a smoker gets cancertroubles; a smoker gets cancer Prolonged Prolonged delaysdelays may prevent a negative may prevent a negative

feedback loop from occurring.feedback loop from occurring.

Synergy-Synergy- Processes and feedbacks in a Processes and feedbacks in a system can interact to amplify the results.system can 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.

Feedback Loops: Feedback Loops: Some negative feedback loops have explicit Some negative feedback loops have explicit

goalsgoals Balancing MetersticksBalancing Metersticks Body TemperatureBody Temperature Blood COBlood CO22 levels levels Etc.Etc.

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.• ElementsElements (represented on the periodic table) are the (represented on the periodic table) are the

distinctive building blocks of matter.distinctive building blocks of matter. Carbon, hydrogen, oxygen, nitrogen, etcCarbon, hydrogen, oxygen, nitrogen, etc

• CompoundsCompounds: two or more different elements held : two or more different elements held together in fixed proportions by chemical bonds.together in fixed proportions by chemical bonds.

COCO22, H, H22O, CO, C66HH1212OO66

AtomsAtoms

Figure 2-4Figure 2-4

IonsIons

An An ionion is an atom or group of atoms with one is an atom or group of atoms with one or more or more net positive or negative electrical 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 concentration of hydrogen ions in one liter of solution.The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution.

00 = strongest acids= strongest acids

7 7 = neutral= neutral

14 = strongest base 14 = strongest base

pH adjectives: pH adjectives:

*acids are “acidic”*acids are “acidic”

*bases are “basic” a.k.a. “alkaline”*bases are “basic” a.k.a. “alkaline”

Figure 2-5Figure 2-5

Figure 2-5Figure 2-5

Compounds and Chemical FormulasCompounds and Chemical Formulas

Chemical formulasChemical formulas are shorthand ways to 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 ) makes the compound HH22OO

(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 ) makes the compound NaClNaCl (sodium chloride (sodium chloride a.k.a. salt).a.k.a. salt).

Organic Compounds: Carbon RulesOrganic Compounds: Carbon Rules

Organic compoundsOrganic compounds contain carbon atomscontain 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--..

Organic compoundsOrganic compounds contain at contain at least two least two carbon atomscarbon atoms combined with each other and combined with each other and with atoms.with atoms. Methane (CHMethane (CH44) is the only exception.) is the only exception. All other compounds (without C) are All other compounds (without C) are inorganicinorganic..

Organic Compounds: Carbon RulesOrganic Compounds: Carbon Rules HydrocarbonsHydrocarbons: compounds of carbon and : compounds of carbon and

hydrogen atoms (e.g. methane (hydrogen atoms (e.g. methane (CHCH44)).)).

Chlorinated hydrocarbonsChlorinated hydrocarbons: compounds of : compounds of carbon, hydrogen, and chlorine atoms (e.g. carbon, hydrogen, and chlorine atoms (e.g. DDT (DDT (CC1414HH99ClCl55)).)).

Simple carbohydratesSimple carbohydrates: certain types of : certain types of compounds of carbon, hydrogen, and oxygen compounds of carbon, hydrogen, and oxygen (e.g. glucose ((e.g. glucose (CC66HH1212OO66)).)).

Complex carbohydrates:Complex carbohydrates: chains of glucose, chains of glucose, such as starch or cellulosesuch as starch or cellulose

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. ProkaryoticProkaryotic cells cells

(bacteria) lack a distinct (bacteria) lack a distinct nucleus.nucleus.

EukaryoticEukaryotic cells (plants 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

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 matter are found in three physical statesphysical states:: solid, liquid, gaseoussolid, liquid, gaseous..

A fourth state, A fourth state, plasmaplasma, is a high energy , 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 as having high or low high or low qualityquality depending on depending on how useful it is to us as how useful it is to us as a resource.a resource. High qualityHigh quality matter is matter is

concentrated and easily concentrated and easily extracted.extracted.

low quality matterlow quality matter is more 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 matterLaw of conservation of matter..

Physical changePhysical change maintains original chemical maintains original chemical composition.composition.

Chemical changeChemical change involves a chemical reaction 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. Mass does not change (Mass does not change (Conservation of MatterConservation of Matter))

Three Types of Atomic Nuclear ChangesThree Types of Atomic Nuclear Changes

Radioactive decayRadioactive decay FissionFission- splitting atoms (like uranium)- splitting atoms (like uranium)

First atomic bombsFirst atomic bombs All nuclear power plantsAll nuclear power plants

FusionFusion- fusing atoms together (like hydrogen)- fusing atoms together (like hydrogen) ““H-Bomb”H-Bomb” Sun and all other starsSun and all other stars 100 million degrees Celsius to begin reaction100 million degrees Celsius to begin reaction

Nuclear Changes: FissionNuclear Changes: Fission

Nuclear fissionNuclear 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

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 fusionNuclear fusion: two isotopes of light elements : 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

+

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 Radiation is commonly used in energy productionenergy production

and and medical applicationsmedical 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).

Matter: Types of PollutantsMatter: Types 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 persistencepersistence:: Degradable Degradable pollutants- can be broken downpollutants- can be broken down

• BiodegradableBiodegradable pollutants- e.g. human sewage pollutants- e.g. human sewage• Slowly degradableSlowly degradable pollutants- e.g. most pollutants- e.g. most

plastics; chlorinated hydrocarbons like DDTplastics; chlorinated hydrocarbons like DDT Nondegradable (a.k.a. persistent)Nondegradable (a.k.a. persistent) pollutants- e.g. pollutants- e.g.

lead, mercury, arseniclead, mercury, arsenic

ENERGYENERGY

EnergyEnergy is the ability to do work and transfer is the ability to do work and transfer heat.heat. Kinetic energyKinetic energy – –

• energy in motionenergy in motion heat, electromagnetic radiationheat, electromagnetic radiation

Potential energyPotential energy – – • stored for possible usestored for possible use

batteries, glucose molecules, any food, water behind a dambatteries, glucose molecules, any food, water behind a dam

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.

NextNext

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.

NextNext

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 The first law of thermodynamicsfirst law of thermodynamics: we cannot : we cannot create or destroy energy (a.k.a. Law of create or destroy energy (a.k.a. Law of Conservation of Energy)Conservation of Energy) We can change energy from one We can change energy from one formform to another. to another.

burning Cheeto:burning Cheeto: Chemical Chemical→ thermal & electromagnetic→ thermal & electromagnetic

The The second law of thermodynamicssecond law of thermodynamics: energy : energy quality always decreases (a.k.a. Law of quality always decreases (a.k.a. Law of Entropy)Entropy) When energy changes from one form to another, When energy changes from one form to another,

it is it is always degradedalways degraded to a more dispersed form. to a more dispersed form. Energy efficiencyEnergy efficiency is a measure of how much 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)

Second Law of Thermodynamics

SUSTAINABILITY AND MATTER SUSTAINABILITY AND MATTER AND ENERGY LAWSAND ENERGY LAWS

Unsustainable Unsustainable High-Throughput EconomiesHigh-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.

NextNext

Fig. 2-15, p. 46

High-quality energy

Matter

Unsustainablehigh-waste

economy

System

Throughputs

Inputs(from environment)

Outputs(into environment)

Low-quality energy (heat)

Waste and pollution

Fig. 2-10, p. 44

Heat

Energy Inputs Throughputs Outputs

Energyresources

Matterresources

Information

Economy

Goods andservices

Waste andpollution

Sustainable Low-Throughput Sustainable Low-Throughput Economies: Learning from NatureEconomies: Learning from Nature

Matter-Recycling-and-Reuse EconomiesMatter-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 It is not sustainablenot sustainable for for growing populations.growing populations.

Only sustainable if population Only sustainable if population stabilizes (ZPG)!stabilizes (ZPG)!

Why not?

Fig. 2-11, p. 45

Fig. 2-12, p. 45

p. 49

p. 49