APES: Chapter 3
Matter and Energy
EQ: What methods and techniques are
used by scientists to study problems?
3-1: Science and Critical Thinking
The scientific method consists of the
following steps:
1. Define the question
2. Research what is already known
3. Form a hypothesis (educated
guess) to be tested- “if then”
statement
a. Models are often used to
approximate or simulate some
aspect of nature being studied.
4. Experiment (test hypothesis)
a. Make observations, collect data
b. Controlled experiments
c. Experimental variable
(experimental group)
i. Control group
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5. Draw conclusions (laws and
theories)
a. Theories: concept supported by
a large number of experiments
b. Law: an explanation or
description of how nature works
http://www.youtube.com/watch?v=zGgIdrD20do
Scientists frequently use one of two
types of reasoning to solve scientific
problems. Inductive reasoning involves
the use of observation, measurement,
and previous experience to arrive at a
general hypothesis.
Deductive reasoning involves an ifthen (logic) statement.
HW #1: Chapter Review (page 61-62) #’s: 3 (all terms), 4, 5, 6.
EQ: How are models and feedback
loops applicable to the study of
environmental science?
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3-2 Models and Behavior of Systems
A system is a set of components that
function and interact in a theoretically
predictable manner (mechanism) and
can be isolated for the purpose of study
(reductionism).
Models (approximate representations
of real systems) can be used to study
systems or test a hypothesis. Models in
the environmental sciences are
frequently mathematical (consisting of
equations). It is important to remember
that models are only as good as the
information used to construct them.
Systems undergo changes when
output (matter, energy, or information) is
fed back into the systems as input.
Positive feedback causes the system to
continue to change in the same direction.
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https://www.youtube.com/watch?v=FM0hczFNDZI
Negative feedback leads to a slowing
down or reversal of the change.
http://www.youtube.com/watch?v=_QbD92p_EVs
Time delays are often found in
complex systems. Time delays may allow
a problem to build up slowly until a
threshold level is reached. (filling a cup
with water until it overflows)
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Synergistic interactions occur when
two or more processes interact to have
an effect greater than either would
separately.
Antagonist interactions tend to cancel
or mediate each other.
Chaotic events tend to be unforeseen
or unpredictable (earthquakes).
EQ: How is the concept of matter
quality important to the study of the
problems we face on the planet?
Section 3-3
Matter is defined as anything that takes
up space and has mass. Matter is found in
two chemical forms:
Elements: pure substances in which
every atom is identical (Periodic Table)
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Compounds: two or more different
elements held together by a chemical bond.
The smallest part of element is an atom
while the smallest part of compound is a
molecule. Atoms and molecules can exist as
charged particles known as ions.
Compounds are frequently classified as
being organic (carbon-based) or inorganic
(lacking carbon).
Important organic compounds include
hydrocarbons, chlorinated hydrocarbons,
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chloroflurocarbons, carbohydrates, lipids,
proteins, and nucleic acids.
Important inorganic compounds include
salts, water, and numerous air pollutants.
http://www.youtube.com/watch?v=w0MWbjIH_Lc#t=62
Matter quality is a measure of how
useful a form of matter is to us based upon
its availability and concentration.
High Quality
- concentrated
- found near the
Earth’s surface
Low Quality
- dilute
- deep underground
or in ocean
Material efficiency (resource
productivity) refers to the amount of material
needed to produce each unit of a good or
service. In developed countries material
efficiency is extremely low (2-6%).
HW #2: Review Questions #’ 8, 9, 11, 12.
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EQ: What are the major ways in which
energy is transferred and how is this
related to the concept of energy quality?
3-4 Energy: Forms and Quality
Energy is defined as the ability to do
work and transfer heat. There are two major
types of energy: kinetic (energy of motion)
and potential (stored energy). Heat is the
total amount of kinetic energy a substance
has while temperature is the average
kinetic energy.
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Heat is transferred in three major ways,
conduction (through contact), convection
(through the movement of heated material),
and radiation. Radiation is the transfer of
energy through space as particles or waves.
Electromagnetic radiation occurs in many
different forms based upon wavelength.
http://www.youtube.com/watch?v=cfXzwh3KadE
Energy quality is a measure of an energy
source’s ability to do work. High quality
energy is concentrated and can perform large
amounts of work (electricity, coal, gasoline,
uranium-235). Low quality energy is
typically dispersed (the total amount of heat
in the ocean).
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EQ: How are the problems of pollution
related to the Law of Conservation of
Matter?
3-5 Physical and Chemical Changes and
the Law of Conservation of Matter
Physical changes do not involve a change
in the chemical composition of a substance
while chemical changes do.
Various elements and compounds can
be changed from one physical or chemical
form to another but we cannot create or
destroy any of the atoms involved (Law of
Conservation of Matter). There is no away in
throw away.
Therefore we must always deal with
certain pollutants the severity of which
depends upon three factors:
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1- Chemical nature
2- Concentration – usually expressed in
parts per million
3- Persistence – how long the pollutant
stays around
Pollutants are classified based upon their
persistence.
1. degradable or nonpersistent
(biodegradable if they can be broken
down by biological processes: like
human sewage)
2. persistent- decades to degradeinsecticides, most plastics
3. Nondegradable - lead, mercury,
arsenic
HW. #3: Review Questions: 21, 22, 23, 24, 25.
EQ: How is the process of nuclear fission
similar/different to the process of nuclear
fusion.
3-6 Nuclear Changes
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In addition to undergoing physical and
chemical change matter can undergo nuclear
decay. This occurs when unstable isotopes
is emitted as radiation and can be extremely
dangerous causing both genetic (DNA)
damage and tissue (burns, miscarriages)
damage.
The amount of time it takes for an
unstable isotope (parent) to decay to a stable
form (daughter) is expressed in terms of a
half-life. The relationship is indirect and
exponential.
Use ratio’s to solve: 1half-life
Time of half life
=
# of half-lives
given amount of time
Nuclear fission occurs when atoms are
split causing a chain reaction once a critical
mass is achieved.
http://www.youtube.com/watch?v=mBdVK4cqiFs#t=50
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Nuclear fusion occurs when atoms
are joined.
http://www.youtube.com/watch?v=Cb8NX3HiS4U
EQ: In what major ways do the Laws of
Thermodynamics impact on the
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environmental problems we face on planet
Earth?
3-7 Two Laws Governing Energy Changes
The First Law of Thermodynamics
states that during changes in matter, energy
is neither created nor destroyed although it
might change from one form to another.
Energy input is always equal energy output.
Energy Input = Energy Output
(We can never get more energy out of a
system than we put in).
The Second Law of Thermodynamics
states that when energy is changed from one
form to another some of it is always
degraded to a lower form (usually heat). We
can never recycle high quality energy to do
work.
Energy Input Quality> Energy Output Quality
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Energy efficiency is a measure of the
amount of useful work is accomplished by
the input of a particular amount of energy.
Ecosystems have efficiencies of about 10%.
3-8 Matter and Energy Change Laws and
Environmental Problems.
Because of the law of the conservation of
matter and the laws of thermodynamics it is
clear that the use of resources always adds
waste heat and waste matter to the
environment.
Modern industrialized countries tend to
be high-waste societies because they
attempt to maintain economic growth by
increasing the flow of matter and energy into
the system.
Matter-recycling economies attempt to
allow for economic growth without depleting
material resources. What is the problem
with matter-recycling economies?
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The only long-term (sustainable) solution
is to switch to a low-waste economy.
HW. #4. Review Questions #’s 27, 29, 31, 32, 33.
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