science, systems, matter, and energy - bioapes 9 the atoms, ions, and molecules that make up matter...
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9/9/2009
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Science, Systems, Matter, and Energy
What do scientists do?Collect data.
Form hypotheses.
Develop theories, models
and laws about how nature
works.
Scientific TheoryWidely tested and
accepted hypothesis.
Scientific LawWhat we find
happening over and
over again in nature.
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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.
Inductive reasoningInvolves using specific observations and
measurements to arrive at a general conclusion or
hypothesis.
Bottom-up reasoning going from specific to
general.
Deductive reasoningUses logic to arrive at a specific conclusion.
Top-down approach that goes from general to
specific.
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.
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Usefulness of modelsComplex 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.
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).
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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.
Elements and CompoundsMatter 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.
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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-)
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The pH (potential of Hydrogen) is the
concentration of hydrogen ions in one liter of
solution.
Figure 2-5
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).
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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.
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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)).
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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).
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.
High Quality Low Quality
Salt
Solid Gas
Coal Coal-fired power plant emissions
GasolineAutomobile emissions
Solution of salt in water
Aluminum oreAluminum can
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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.
Energy is given off during the reaction as a product.
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.
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Large, complex organic
molecules (macromolecules)
make up the basic molecular
units found in living
organisms.Complex carbohydrates
Proteins
Nucleic acids
Lipids
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
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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).
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Nuclear fission: nuclei of certain isotopes
with large mass numbers are split apart
into lighter nuclei when struck by neutrons.
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Uranium-235
Neutron
Uranium-235
Energy
Fission
fragment
Fission
fragment
n
n
n
n
n
n
Energy
Energy
Energy
Nuclear fusion: two isotopes of light elements are forced together at extremely high temperatures until they fuse to form a heavier nucleus.
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Neutron
+
Hydrogen-2
(deuterium nucleus)
Hydrogen-3
(tritium nucleus)
+
Proton Neutron
100
million °C
Energy
+
Helium-4 nucleus
ProductsReaction
ConditionsFuel
+
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
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Many different forms of electromagnetic
radiation exist, each having a different
wavelength and energy content.
Organisms vary
in their ability to
sense different
parts of the
spectrum.
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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 movevehicles and other things)
High-temperature heat(1,000–2,500°C) forindustrial processes andproducing 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 Relative
Energy Quality
(usefulness)
Energy Tasks
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.
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Chemical
energy
(food)
Solar
energy
Waste
Heat
Waste
HeatWaste
Heat
Waste
Heat
Mechanical
energy
(moving,
thinking,
living)
Chemical
energy
(photosynthesis)
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Matter-Recycling-and-Reuse Economies:
Working in CirclesMimics nature by recycling and reusing, thus reducing
pollutants and waste.
It is not sustainable for growing populations.
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