Transcript Fig. 3-2 p. 41 Models and Behavior of Systems Inputs

Science, Systems, Matter, and Energy
G. Tyler Miller’s
Living in the Environment
13th Edition
Chapter 3
Key Concepts
Science as a process for understanding
Components and regulation of systems
Matter: forms, quality, and how it
changes; laws of matter
Energy: forms, quality, and how it
changes; laws of energy
Nuclear changes and radioactivity
Science, and Critical Thinking
Ask a question
 Scientific data
 Scientific hypotheses
 Scientific (natural) laws
 Scientific theories
Do experiments
and collect data
Interpret data
Formulate
hypothesis
to explain data
Well-tested and
accepted patterns
In data become
scientific laws
Do more
Experiments to
test hypothesis
 Consensus science
Revise hypothesis
if necessary
 Frontier science
Well-tested and
accepted
hypotheses
become
scientific theories
Fig. 3-2 p. 41
Models and Behavior of Systems
Inputs- matter, energy, information
Flows (throughputs) – of matter or energy
Stores (storage areas) – place where energy
or matter can accumulate for various lengths of time
(your body, water on earth)
Outputs-certain forms of matter or energy leave
the system and sink or absorbs into the environment
(air, water, soil)
System Regulation
 Positive Feedback
 Homeostasis
 Negative Feedback
 Time Delay –
 Synergy
corrective action can
be too late -smokers
Fig. 3-3 p. 46
Feedback Loops
•Positive Feedback- ex: collecting
interest in a bank account.
•Negative feedback- ex:
thermostat in a house, when the
house reaches or exceeds the set
temp, the air shuts off.
Threshold Level
•Point when a fundamental shift occurs
•Ex: your body becomes so overheated that you pass out. Your
body has a threshold temperature and when it is reached, there
is a change
•Ex: Easter Island exceeded threshold of resource use.
•Time delays can slow negative feedback
and more rapidly approach threshold
levels – population growth, unknown
pollution, degradation of forests from air
pollution.
Mt. Mitchell –Acid Rain Damage
Law of Conservation of Problems
•The solution to one problem usually creates one or
more new problems
•Ex: chemical fertilizers –increases crop productivity
can become widespread, new problem of
overstimulation of non-target plants and pollution to
water supply
•Do benefits outweigh potential harm?
•Not enough data
•Imperfect models
•Different assumptions
Environmental Surprises
•Result of
•Shifts when threshold is met
•Synergistic interaction
•Unpredictable or natural events (weather,
invasives)
•Strategies to reduce:
•Increase research
•Better models
•Prevent/reduce pollution, reduce population,
benign products
Matter: Forms, Structure, and Quality
Elements -building block of matter
Compounds-two or more elements
Molecules-two or more atoms of same element
Mixtures-various elements, compounds or both
Atoms
Subatomic Particles
Protons
Neutrons
Electrons
Atomic Characteristics
Atomic number
Ions
Atomic mass
Isotopes
Examples of Atoms
Fig. 3-4 p. 48
Chemical Bonds
Chemical formulas- # of atoms in compound
Ionic bonds-
oppositely charged
Metal and nonmetal
Covalent bonds
–valence
Electron sharing (less water soluble than ionic bonds)
Hydrogen bonds-
H to
Electronegative, weakest bond, occurs in organic and inorganic
Organic Compounds
Organic vs. inorganic compounds
Hydrocarbons- C and H
Chlorinated hydrocarbons –C, H, and Cl
Chlorofluorocarbons- C and Fl
Simple carbohydrates- C, H, O
Complex carbohydratesProteins- monomers of amino acids
polymer- 2 or more simple sugars
Genetic Material
Nucleic acids
Genes
Chromosomes
Gene mutations
Fig. 3-6 p. 50
The Four States of Matter
Solid
Liquid
Gas
Plasma
Fig. 3-7 p. 50
Matter Quality and Material Efficiency
 High-quality matter- near
Earth’s surface
 Low-quality matter
Dilute, deep underground, ocean, atmosphere
 Material efficiency
(resource productivity)
Total amount of material needed to produce each
unit of goods or services. 2-6% of matter used
in developed countries provides useful goods.
Fig. 3-8 p. 51
Energy: Forms
Kinetic energy Potential energy
Heat
Fig. 3-9 p. 52
Transfer of Heat Energy
Convection
Heating water in the bottom of a pan
causes some of the water to vaporize
into bubbles. Because they are
lighter than the surrounding water,
they rise. Water then sinks from the
top to replace the rising bubbles.This
up and down movement (convection)
eventually heats all of the water.
Conduction
Heat from a stove burner causes
atoms or molecules in the pan’s
bottom to vibrate faster. The vibrating
atoms or molecules then collide with
nearby atoms or molecules, causing
them to vibrate faster. Eventually,
molecules or atoms in the pan’s
handle are vibrating so fast it
becomes too hot to touch.
Radiation
As the water boils, heat from the hot
stove burner and pan radiate into the
surrounding air, even though air
conducts very little heat.
Fig. 3-11 p. 553
Energy: Quality
High-quality
energy
Low-quality
energy
Fig. 3-12 p. 53
Physical and Chemical Changes
Fig. In text p. 54
The Law of Conservation of Matter
Matter is not consumed
Matter only changes form
There is no “away”
Matter and Pollution
 Chemical nature of pollutants
 Concentration
 Persistence
 Degradable (nonpersistent) pollutants
 Biodegradable pollutants
 Slowly degradable (persistent) pollutants
 Nondegradable pollutants
Nuclear Changes
Natural radioactive decay
Radioisotope –
–measured by half life
ex: Uranium 235 and 238, different half-lives =different energy
Output or hazard
Gamma rays
Alpha particles
Beta particles
Half life (See Table 3-2 p. 56)
Ionizing radiation
–high energy
Electromagnetic radiation
Fig. 3-13 p. 56
–radiation from radioisotopes, harmful, often in normal
Activities, can be in large doses (Chernobyl or 3 mile island
Nuclear Reactions
Fission
Fig. 3-16 p. 57
Fusion
Fig. 3-17 p. 58
Laws Governing Energy Changes
First Law of Thermodynamics (Energy)
 Energy is neither created nor destroyed
 Energy only changes form
 You can’t get something for nothing
ENERGY IN = ENERGY OUT
Laws Governing Energy Changes
Second Law of Thermodynamics
 In every transformation, some energy is
converted to heat
 You cannot break even in terms of
energy quality
Connections: Matter and Energy Laws
and Environmental Problems
 High-throughput (waste) economy
 Matter-recycling economy
 Low-throughput
economy
Fig. 3-20 p. 60;
see Fig. 3-21 p. 61