chapter 2: science, matter , energy and systems
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Chapter 2: Science, Matter , Energy and Systems. APES, Fall 2013. Controlled experiment (case study). F. Herbert Bormann, Gene Likens, et al.: Hubbard Brook Experimental Forest in NH (U.S.) - PowerPoint PPT PresentationTRANSCRIPT
Chapter 2:Science, Matter, Energy and Systems
APES, Fall 2013
Controlled experiment (case study)F. Herbert Bormann, Gene Likens, et al.:
Hubbard Brook Experimental Forest in NH (U.S.)
Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site)
The Effects of Deforestation on the Loss of Water and Soil Nutrients
What is scienceConcept 2-1 Scientists collect data and
develop theories, models, and laws about how nature works.
Science Is a Search for Order in Nature Identify a problemFind out what is known about the problemAsk a question to be investigatedGather dataHypothesizeMake testable predictions Keep testing and making observationsAccept or reject the hypothesis
Scientific Theories and Laws Are the Most Important Results of ScienceScientific theory – Explanation of what happens
Widely testedSupported by extensive evidenceAccepted by most scientists in a particular area
Scientific law, law of nature – Statement of what happensWidely testedSupported by extensive evidenceAccepted by most scientists in a particular area
Paradigm shift
The Results of Science Can Be Tentative, Reliable, or UnreliableTentative science, frontier science
Reliable science
Unreliable science
(but all science is tentative, right?)Non-science??
Science Focus: Statistics and ProbabilityStatistics
Collect, organize, and interpret numerical data
ProbabilityThe chance that something will happen or be
valid
2-2 What is matter?Concept 2-2 Matter consists of elements and
compounds, which are in turn made up of atoms, ions, or molecules.
Matter Consists of Elements and CompoundsMatter
Has mass and takes up spaceElements
Unique propertiesCannot be broken down chemically into other
substancesCompounds
Two or more different elements bonded together in fixed proportions
Elements important to Env Sci
Ions Important to Env Sci
Atoms, Ions, and Molecules Are the Building Blocks of Matter Atomic theorySubatomic particles
Protons (p) with positive charge and neutrons (0) with no charge in nucleus
Negatively charged electrons (e) orbit the nucleusMass number
Protons plus neutronsIsotopes
Variants of an element with different massesAlso different number of neutrons
Atoms, Ions, and Molecules Are the Building Blocks of Matter Ions
Gained or lost electronsForm ionic compounds
pHMeasure of acidity or basicityH+ and OH-1-7 = acidic, 7-14 = basic (7 = neutral)
Atoms, Ions, and Molecules Are the Building Blocks of Matter Molecule
Two or more atoms of the same or different elements held together by chemical bonds
Chemical formulaSymbols and numbers used to represent the
elements in a compound and their relative proportions
Model of a Carbon-12 Atom
Loss of NO3- from Deforested Watershed
Organic Compounds Are the Chemicals of LifeInorganic compounds – no C+HOrganic compounds – CH
Hydrocarbons and chlorinated hydrocarbonsSimple carbohydrates - CHOMacromolecules: complex organic molecules
Complex carbohydrates - CHO Proteins - CHON, amino acid chain Nucleic acids - CHONPS, DNA and RNA, GCTA,
GCAU Lipids - large, water insoluble, CHO
Matter Comes to Life through Genes, Chromosomes, and CellsCells: fundamental units of lifeGenes: sequences of nucleotides within the
DNAChromosomes: composed of many genes
A human body contains trillionsof cells, each with an identical setof genes.
Each human cell (except for redblood cells) contains a nucleus.
Each cell nucleus has an identical setof chromosomes, which are found inpairs.
A specific pair of chromosomescontains one chromosome from eachparent.
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.
Some Forms of Matter Are More Useful than OthersHigh-quality matter: easily used by people
Low-quality matter: Not easily used
High Q Low Q Figure 2.6High-quality matter is fairly easy to extract and is highly concentrated;
Low-quality matter is not highly concentrated and is more difficult to extract than high-quality matter.
WATER can even be low quality, IF…
2-3 How Can Matter Change?Concept 2-3 When matter undergoes a
physical or chemical change, no atoms are created or destroyed (the law of conservation of matter).
Matter Undergoes Physical, Chemical, and Nuclear ChangesPhysical changeChemical change, chemical reactionNuclear change
Natural radioactive decay Radioisotopes: unstable
Nuclear fissionNuclear fusion
Decay Alpha particle(helium-4 nucleus)
Radioactive isotope
Beta particle (electron)
Gamma rays
Fission
FusionProton Neutron
Hydrogen-2(deuterium nucleus)
Hydrogen-3(tritium nucleus)
100million °C
Helium-4 nucleus
Energy
Neutron
We Cannot Create or Destroy MatterLaw of conservation of matterMatter consumption
Matter is converted from one form to another
2-4 What is Energy and How Can It Be Changed?Concept 2-4A When energy is converted
from one form to another in a physical or chemical change, no energy is created or destroyed (first law of thermodynamics).
Concept 2-4B Whenever energy is changed from one form to another, we end up with lower- quality or less usable energy than we started with (second law of thermodynamics).
Energy Comes in Many FormsKinetic energy
Heat Transferred by radiation, conduction, or convection
Electromagnetic radiationPotential energy
Stored energy In the nucleus (nuclear), in bonds (chemical),
gravitationalCan be changed into kinetic energy
Some Types of Energy Are More Useful Than OthersHigh-quality energyLow-quality energy
The 2nd Law of Thermodynamics in Living Systems
Energy Changes Are Governed by Two Scientific LawsFirst Law of Thermodynamics
Energy input always equals energy outputSecond Law of Thermodynamics
Energy always goes from a more useful to a less useful form when it changes from one form to another
Also, (The zeroth law – seriouslyA=B, B=C, then A=C for temperatures.)
Energy efficiencyIn cars – 6% of gasoline combustion = kinetic
energy. 94% = heat.
Incandescent bulbs – 5% light, 95% heat
Estimated: 84% of E in US is wasted, 41% as heat, 43% wasted
2-5 What Are Systems and How Do They Respond to Change?Concept 2-5A Systems have inputs, flows,
and outputs of matter and energy, and their behavior can be affected by feedback.
Concept 2-5B Life, human systems, and the earth’s life support systems must conform to the law of conservation of matter and the two laws of thermodynamics.
Systems Have Inputs, Flows, and OutputsSystem
Inputs from the environmentFlows, throughputsOutputs
Systems Respond to Change through Feedback LoopsPositive feedback loopNegative, or corrective, feedback loop
Positive feedback =/= Good!
Negative feedback maintains conditions
Time Delays Can Allow a System to Reach a Tipping Point
Time delays varyBetween the input of a feedback stimulus and
the response to itTipping point, threshold level
Causes a shift in the behavior of a system
System Effects Can Be Amplified through SynergySynergistic interaction, synergy
HelpfulHarmful
E.g., Smoking and inhaling asbestos particles
Human Activities Can Have Unintended Harmful ResultsDeforested areas turning to desertCoral reefs dyingGlaciers meltingSea levels rising
FRQ’s Sci notation is useful!!