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Science, Matter, Energy, and Systems

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Science, Matter, Energy, and Systems Chapter 2 – PowerPoint PPT presentation

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Title: Science, Matter, Energy, and Systems


1
Science, Matter, Energy, and Systems
  • Chapter 2

2
Core Case Study Carrying Out a Controlled
Scientific Experiment
  • 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)

3
The Effects of Deforestation on the Loss of Water
and Soil Nutrients
4
2-1 What Is Science?
  • Concept 2-1 Scientists collect data and develop
    theories, models, and laws about how nature
    works.

5
Science Is a Search for Order in Nature (1)
  • Science an endeavor to discover how nature
    works and to use that knowledge to make
    predictions about what is likely to happen in
    nature
  • Cause-and-Effect Patterns
  • Scientific Process
  • Identify a problem
  • Find out what is known about the problem
  • Ask a question to be investigated
  • Gather data
  • Hypothesize
  • Make testable predictions
  • Keep testing and making observations
  • Accept or reject the hypothesis

6
Science Is a Search for Order in Nature (2)
  • Important features of the scientific process
  • Curiosity
  • Skepticism
  • Peer review
  • Reproducibility
  • Openness to new ideas

7
The Scientific Process
8
Science Focus Easter Island Revisions to a
Popular Environmental Story
  • Some revisions in a popular environmental story
  • Polynesians arrived about 800 years ago
  • Population may have reached 3000
  • Used trees in an unsustainable manner, but rats
    may have multiplied and eaten the seeds of the
    trees

9
Video ABC News Easter Island
10
Scientists Use Reasoning, Imagination, and
Creativity to Learn How Nature Works
  • Important scientific tools
  • Inductive reasoning using specific observations
    and measurements to arrive at a general
    conclusion or hypothesis bottom-up reasoning
    (specific to general)
  • Deductive reasoning using logic to arrive at a
    specific conclusion based on a generalization or
    premise top-down reasoning (general to
    specific)
  • Scientists also use
  • Intuition
  • Imagination
  • Creativity

11
Scientific Theories and Laws Are the Most
Important Results of Science
  • Scientific theory overwhelming body of
    observation and measurements support a scientific
    hypothesis
  • Widely tested
  • Supported by extensive evidence
  • Accepted by most scientists in a particular area
  • Scientific law, law of nature well tested and
    widely accepted description of what we find
    happening over and over again in the same way in
    nature
  • Paradigm shift new discoveries and ideas
    overthrow a well accepted theory or law majority
    of scientists accept a new paradigm

12
Science Focus The Scientific Consensus over
Global Warming
  • How much has the earths atmosphere warmed during
    the last 50 years?
  • How much of this warming is due to human
    activity?
  • How much is the atmosphere likely to warm in the
    future?
  • Will this affect climate?
  • 1988 Intergovernmental Panel on Climate Change
    (IPCC)

13
The Results of Science Can Be Tentative,
Reliable, or Unreliable
  • Tentative science, frontier science preliminary
    results not widely tested or accepted by peer
    review not considered reliable
  • Reliable science data, hypotheses, theories,
    and laws that are widely accepted based on
    self-correcting testing, peer review,
    reproducibility, and debate
  • Unreliable science hypotheses and results are
    presented as reliable without having undergone
    peer review or have been discarded by peer review

14
Environmental Science Has Some Limitations
  • Science can disprove things, but never prove
    anything absolutely due to degree of uncertainty
    in measurements, models, and observations
  • Establish particular hypotheses, theories, or
    laws have a high probability of being true while
    not being absolute
  • Bias can be minimized by high standards and peer
    review
  • Statistical methods may be used to estimate very
    large or very small numbers
  • Environmental phenomena involve interacting
    variables and complex interactions too costly so
    create models
  • Scientific process is limited to the natural
    world

15
Science Focus Statistics and Probability
  • Statistics
  • Collect, organize, and interpret numerical data
  • Probability
  • The chance that something will happen or be valid

16
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.

17
Matter Consists of Elements and Compounds
  • Matter
  • Has mass and takes up space
  • Elements
  • Unique properties
  • Cannot be broken down chemically into other
    substances
  • Compounds
  • Two or more different elements bonded together in
    fixed proportions

18
Elements Important to the Study of Environmental
Science
19
Atoms, Ions, and Molecules Are the Building
Blocks of Matter (1)
  • Atomic theory - all elements are made of atoms
    (smallest unit of matter to which an element can
    be divided and retain chemical properties)
  • Subatomic particles
  • Protons (p) with positive charge and neutrons (0)
    with no charge in nucleus
  • Negatively charged electrons (e) orbit the
    nucleus
  • Atomic number protons in nucleus
  • Mass number - protons plus neutrons
  • Isotopes form of elements with same atomic
    number but different mass numbers

20
Model of a Carbon-12 Atom
21
Atoms, Ions, and Molecules Are the Building
Blocks of Matter (2)
  • Ions atom or group of atoms with one or more
    net positive or negative charges
  • Gain or lose electrons
  • Form ionic compounds
  • Nitrate
  • pH
  • Measure of acidity
  • H and OH-
  • Pure water pH of 7, neutral solution

22
Animation pH scale
23
Atoms, Ions, and Molecules Are the Building
Blocks of Matter (3)
  • Molecule
  • Two or more atoms of the same or different
    elements held together by chemical bonds
  • Chemical formula
  • Number and each type atom or ion in a compound
  • Symbol for each element and subscripts represent
    number of atoms or ions

24
Ions Important to the Study of Environmental
Science
25
Compounds Important to the Study of Environmental
Science
26
Organic Compounds Are the Chemicals of Life
  • Inorganic compounds
  • all other compounds
  • Organic compounds
  • At least 2 carbon atoms combined with atoms of
    one or more elements CH4
  • Hydrocarbons and chlorinated hydrocarbons
  • Simple carbohydrates (simple sugars)
  • Macromolecules complex organic molecules form
    when monomers link together
  • Complex carbohydrates (polymers)
  • Proteins (polymers)
  • Nucleic acids (polymers)
  • Lipids

27
Loss of NO3- from a Deforested Watershed
28
Matter Comes to Life through Genes, Chromosomes,
and Cells
  • Cells fundamental units of life
  • Genes sequences of nucleotides within the DNA
  • Chromosomes composed of many genes

29
Cells, Nuclei, Chromosomes, DNA, and Genes
30
Matter Occurs in Various Physical Forms
  • Differ in spacing and orderliness of atoms, ions,
    or molecules
  • Solid
  • Most compact, orderly arrangement
  • Liquid
  • Gas
  • Least compact, orderly arrangement

31
Some Forms of Matter Are More Useful than Others
  • Matter Quality measure of how useful a form of
    matter is to humans as a resource, based on
    availability and concentration
  • High-quality matter
  • Highly concentrated, found near earths surface,
    great potential as resource
  • Low-quality matter
  • Not highly concentrated, found deep underground,
    little potential as resource

32
Examples of Differences in Matter Quality
33
Animation Subatomic particles
34
Animation Carbon bonds
35
Animation Ionic bonds
36
Animation Atomic number, mass number
37
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).

38
Matter Undergoes Physical, Chemical, and Nuclear
Changes
  • Physical change
  • Chemical change, chemical reaction
  • Nuclear change
  • Natural radioactive decay
  • Radioisotopes unstable
  • Nuclear fission
  • Nuclear fusion

39
Types of Nuclear Changes
40
Fig. 2-7a, p. 41
41
Radioactive decay
Alpha particle (helium-4 nucleus)
Radioactive isotope
Gamma rays
Beta particle (electron)
Fig. 2-7a, p. 41
42
Fig. 2-7b, p. 41
43
Nuclear fission
Uranium-235
Fission fragment
Energy
n
n
Neutron
n
n
Energy
Energy
n
n
Uranium-235
Fission fragment
Energy
Fig. 2-7b, p. 41
44
Fig. 2-7c, p. 41
45
Nuclear fusion
Reaction conditions
Fuel
Products
Proton
Neutron
Helium-4 nucleus
Hydrogen-2 (deuterium nucleus)
100 million C
Energy
Hydrogen-3 (tritium nucleus)
Neutron
Fig. 2-7c, p. 41
46
Stepped Art
Fig. 2-7, p. 41
47
We Cannot Create or Destroy Matter
  • Law of conservation of matter
  • Matter consumption
  • Matter is converted from one form to another

48
Animation Total energy remains constant
49
Animation Half-life
50
Animation Isotopes
51
Animation Positron-emission tomography (PET)
52
Video Nuclear energy
53
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).

54
Energy Comes in Many Forms
  • Kinetic energy
  • Heat
  • Transferred by radiation, conduction, or
    convection
  • Electromagnetic radiation
  • Potential energy
  • Stored energy
  • Can be changed into kinetic energy

55
The Spectrum of Electromagnetic Radiation
56
15
10
Energy emitted from sun (kcal/cm2/min)
5
Visible
Infrared
Ultraviolet
0
2
0.25
1
2.5
3
Wavelength (micrometers)
Fig. 2-8, p. 42
57
The Second Law of Thermodynamics in Living
Systems
58
Mechanical energy (moving, thinking, living)
Chemical energy (food)
Chemical energy (photosynthesis)
Solar energy
Waste heat
Waste heat
Waste heat
Waste heat
Fig. 2-9, p. 43
59
Some Types of Energy Are More Useful Than Others
  • High-quality energy
  • Low-quality energy

60
Energy Changes Are Governed by Two Scientific Laws
  • First Law of Thermodynamics
  • Energy input always equals energy output
  • Second Law of Thermodynamics
  • Energy always goes from a more useful to a less
    useful form when it changes from one form to
    another
  • Energy efficiency or productivity

61
Active Figure Energy flow
62
Active Figure Visible light
63
Animation Martian doing mechanical work
64
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
    earths life support systems must conform to the
    law of conservation of matter and the two laws of
    thermodynamics.

65
Systems Have Inputs, Flows, and Outputs
  • System
  • Inputs from the environment
  • Flows, throughputs
  • Outputs

66
Inputs, Throughput, and Outputs of an Economic
System
67
Throughputs
Outputs
Energy Inputs
Energy resources
Heat
Matter resources
Waste and pollution
Economy
Goods and services
Information
Fig. 2-10, p. 44
68
Systems Respond to Change through Feedback Loops
  • Positive feedback loop
  • Negative, or corrective, feedback loop

69
Positive Feedback Loop
70
Negative Feedback Loop
71
Time Delays Can Allow a System to Reach a Tipping
Point
  • Time delays vary
  • Between the input of a feedback stimulus and the
    response to it
  • Tipping point, threshold level
  • Causes a shift in the behavior of a system

72
System Effects Can Be Amplified through Synergy
  • Synergistic interaction, synergy
  • Helpful
  • Harmful
  • E.g., Smoking and inhaling asbestos particles

73
Human Activities Can Have Unintended Harmful
Results
  • Deforested areas turning to desert
  • Coral reefs dying
  • Glaciers melting
  • Sea levels rising

74
Animation Economic types
75
Animation Feedback control of temperature
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