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
Stepped Art
Fig. 2-1, p. 28
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2-1 What Is Science?

• Concept 2-1 Scientists collect data and develop
  theories, models, and laws about how nature
  works.

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Science Is a Search for Order in Nature (1)

• 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

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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
Scientists Use Reasoning, Imagination, and
Creativity to Learn How Nature Works

• Important scientific tools
• Inductive reasoning
• Deductive reasoning
• Scientists also use
• Intuition
• Imagination
• Creativity

8
The Scientific Process
Identify a problem
Find out what is known about the
problem (literature search)
Ask a question to be investigated
Perform an experiment to answer the question and
collect data
Scientific law Well-accepted pattern in data
Analyze data (check for patterns)
Propose an hypothesis to explain data
Use hypothesis to make testable predictions
Perform an experiment to test predictions
Make testable predictions
Accept hypothesis
Revise hypothesis
Test predictions
Scientific theory Well-tested and widely
accepted hypothesis
Fig. 2-2, p. 30
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Scientific Theories and Laws Are the Most
Important Results of Science

• Scientific hypothesis a possible and testable
  explanation of what is observed in nature (edu.
  Guess)
• Scientific theory
• Supported by extensive evidence (tested many
  times)
• Accepted by most scientists in a particular area
• Explains
• Scientific law, law of nature
• Based on countless observations, tests
• Describes

10
Read guest essay on global warming

• The Scientific Consensus About Global Warming
• John Harte

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What is Global Warming?

• Talking about the warming of the air atmosphere
  closest to ground.
• More energy from the sun is kept at surface of
  earth than usual
• Scientist are looking at some fundamental
  questions
• Is this actually occurring? (1C increase in
  10yrs)
• Did humans cause this (cars, burning forests
  which add greenhouse gases like CO2 to atmo)
• What could be result? (complex Q, complex A)

12
Economics/Politics/Ethics and Science

• Any other possible causes?
• Yes, changes in the Sun, Volcanoes, variation in
  earths orbit
• Has this happened in the past, before humans?
• Yes, many times
• Ramifications and Blame?
• Industries, Nations, Consumers
• Scare Tactic?
• Big business wants to paint warnings as a method
  of societal controlby government and shift the
  blame/concern

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Stepped Art
Fig. 19-7, p. 507
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The Results of Science Can Be Tentative,
Reliable, or Unreliable

• Tentative science, frontier science (hypothesis)
• Reliable science
• (theory)
• Unreliable science
• (a theory based on false, misleading or no
  evidence, faith)

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Environmental Science Has Some Limitations

• Particular hypotheses, theories, or laws have a
  high probability of being true while not being
  absolute
• Bias has to be minimized by scientists, for
  validity
• Statistical methods may be used to estimate very
  large or very small numbers
• Environmental phenomena involve many interacting
  variables and complex interactions, testability
  limitations
• Scientific process is limited to the natural
  world (can not prove or disprove ethical or moral
  questions)

16
Science Focus Statistics and Probability

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

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Animation pH scale
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2-2 What Is Matter?

• Concept 2-2 Matter consists of elements and
  compounds, which are in turn made up of atoms,
  and/or molecules.

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What is matter?

• Is everything made out of matter?
• Explain your answer.

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Matter

• Has mass and takes up space

21

• What is the difference between elements,
  compounds and mixtures?

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Matter Consists of Elements and Compounds

• Elements
• Unique properties
• Cannot be broken down chemically into other
  substances
• Compounds
• Two or more different elements chemically bonded
  together in fixed proportion
• Mixtures 2 or more elements, compounds or other
  mixtures physically mixed together

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Elements you might consider important
environmentally
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Elements Important to the Study of Environmental
Science
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What is a compound? What is a mixture?

• Orange Juice
• Ketchup
• Distilled Water
• Steel
• Water from a drinking fountain

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What is the smallest amount of an element you can
have that has all of its properties?
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Model of a Carbon-12 Atom
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Animation Subatomic particles
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Atoms, Ions, and Molecules Are the Building
Blocks of Matter (1)

• Atomic theory
• Subatomic particles
• Protons (p) with positive charge and neutrons (n)
  with no charge in nucleus (all the mass)
• Negatively charged electrons (e) orbit the
  nucleus (almost no mass)

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Numbers in chemistry

• Atomic number
• of protons in each atom
• Every element has a different of protons
• Mass number
• Protons plus neutrons

31
Need a Periodic Table

• How many protons does Helium have? Argon?
• What is the atomic number of Mercury, Nitrogen?
• How many electrons does a stable atom of Oxygen
  have, how do you know?
• What is the mass number of the most common form
  of Carbon, Lead

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Animation Atomic number, mass number
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Atoms, Ions, and Molecules Are the Building
Blocks of Matter (2)

• Isotopes
• Number of neutrons vary, properties same
• Most common version founded by rounding atomic
  mass
• Ions
• Gain or lose electrons (exteme bonding)
• Form ionic compounds

34
Need a periodic table

• What is the most common isotope of Sulfur?
  Magnesium?
• Determine how many electrons are lost or gained
  when atom of Fluorine or Boron is ionized
• How are the most common ions of Oxygen and
  Lithium written

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Animation Isotopes
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Animation Ionic bonds
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Chemical Formulas

• SO42-
• 2H20

• Chemical formula
• Recipe for 1 molecule of a chemical Compound
• Letters
• Numbers
• Signs

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Ions Important to the Study of Environmental
Science
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Why are ions important?

• Reactivity
• Ions with an 1 extra electron or lacking one
  electron react more strongly
• The stronger the reaction means more energy is
  released or absorbed
• Greater effects

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Loss of NO3- from a Deforested Watershed
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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

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Compounds Important to the Study of Environmental
Science
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Animation Carbon bonds
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pH the acid test

• pH
• Measure of acidity of Hydrogen ions in a
  certain volume of a solution
• Solution can be neutral , acidic, or basic
• Defined by relative amounts of H and OH-
• Something on either end of scale has a tendency
  to react strongly
• Scale is exponential in amount, 10x for each step

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Acid lab
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Organic Compounds Are the Chemicals of Life

• Organic compounds contain 2 Carbon atoms
• 1 exception Methane CH4
• Types
• Hydrocarbons and chlorinated hydrocarbons
• Simple carbohydrates
• Macromolecules complex organic molecules
• Complex carbohydrates
• Proteins
• Nucleic acids
• Lipids
• Inorganic compounds any other compound not
  organic

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Arrange in terms of size

• An Artery
• Cell
• Chromosomes
• DNA Molecules
• Electron
• Genes
• Nucleus (in terms of cells, not atoms)
• One Atom
• Proton

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Stepped Art
Fig. 2-5, p. 38
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Matter Comes to Life through Genes, Chromosomes,
and Cells

• Cells fundamental units of life
• Genes sequences of nucleotides within the DNA ,
  instructions for 1 trait
• Chromosomes composed of many genes

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Matter Occurs in Various Physical Forms

• Solid
• Liquid
• Gas (plasma)

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Usefulness of matter

• High-quality matter
• Highly concentrated
• Near surface
• Great potential
• Low-quality matter

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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).

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Matter Undergoes Physical, Chemical, and Nuclear
Changes

• Physical change chemical composition does not
  change (tear apart paper)
• Chemical change, chemical reaction permanent
  chemical composition change (burning wood to make
  smoke with CO2 )

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Nuclear Change

• Nuclear change
• Natural radioactive decay
• Radioisotopes unstable
• Nuclear fission
• Nuclear fusion
• Difference between Nuclear and Chemical change
• Chemical change alters bonds between atoms
  (electrons, molecules)
• Nuclear change changes the nucleus of an atom
  (change of protons, neutrons) (high energy)

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Stepped Art
Fig. 2-7, p. 41
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Fig. 2-7a, p. 41
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Radioactive decay
Alpha particle (helium-4 nucleus)
Radioactive isotope
Gamma rays
Beta particle (electron)
Fig. 2-7a, p. 41
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Fig. 2-7b, p. 41
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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
60
Fig. 2-7c, p. 41
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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
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Animation Half-life
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Video Nuclear energy
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We Cannot Create or Destroy Matter

• Law of conservation of matter
• Matter consumption
• Matter is converted from one form to another
• Matter is never lost

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Animation Total energy remains constant
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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).

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Energy Comes in Many Forms

• Kinetic energy
• Energy of organized motion (most useful)
• Heat (energy of unorganized motion (not as good)
• Transferred by radiation, conduction, or
  convection
• Electromagnetic radiation KE transmitted as
  waves
• Potential energy
• Stored energy (GPE, EPE, chemical, nuclear)
• Can be changed into kinetic energy

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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
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Active Figure Visible light
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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

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Some Types of Energy Are More Useful Than Others

• High-quality energy
• Low-quality energy
• Determined by the capacity to do useful work

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The Second Law of Thermodynamics in Living
Systems
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Active Figure Energy flow
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Do Personal Energy Audit Lab
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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.

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Systems Have Inputs, Flows, and Outputs

• System is a set of components that function and
  interact in some regular way
• Parts of systems
• Inputs from the environment
• Flows, throughputs
• Outputs to the environment

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Inputs, Throughput, and Outputs of an Economic
System
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Animation Economic types
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Systems Respond to Change through Feedback Loops

• Feedback Any process which increases or
  decreases change to a system
• Feedback stimulus event or action which
  initiates the process of change(cycle or loop)
• Examples (cutting down trees) (paying farmers not
  to farm marginal land)

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Positive Feedback loop

• Positive or amplified feedback loop causes a
  system to change further in the same direction
• Cutting trees in a valley event that started a
  loop concerning the increasing environmental
  health problems of the valley

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Decreasing vegetation...
...which causes more vegetation to die.
...leads to erosion and nutrient loss...
Fig. 2-11, p. 45
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Negative feedback loop

• Negative, or corrective, feedback loop causes a
  change in the opposite direction to which it was
  moving
• Automatic thermostats in homes
• Increased recycling of aluminum, in terms of
  mining

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House warms
Temperature reaches desired setting and furnace
goes off
Furnace on
House cools
Temperature drops below desired setting and
furnace goes on
Fig. 2-12, p. 45
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Animation Feedback control of temperature
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What kind of feedback loop occurs

• Enforcement of no cell phones in class room on
  student achievement, class discipline?
• Commitment to recycling more at lunch on keeping
  the lunchroom clean,
• Commitment to quotas on the number of tuna that
  can be caught during a season to the health of
  the tuna population
• Lemmings

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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 by the system
• Tipping point, threshold level
• Causes a shift in the behavior of a system
• Land unable to support trees, crops
• Once crossed, takes a lot of time, change in
  conditions to revert

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Haiti and deforestation
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System Effects Can Be Amplified through Synergy

• Synergistic interaction, synergy
• 2 or more processes interact so combined effect
  is greater than either can produce separately
• Helpful (1 person, group working on a cause)
• Harmful
• E.g., Smoking and inhaling asbestos particles and
  risk of cancer
• 10 fold, 5 fold, combined 50 fold

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Human Activities Can Have Unintended Harmful
Results

• Deforested areas turning to desert (Haiti)
• Associated with Global Warming
• Coral reefs dying (Belize, Australia)
• Glaciers melting (US, Europe)
• Sea levels rising (global)

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Your Questions?

• Connected to the information presented in this
  chapter

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UN Project Questions for the chapter

• What are the major forms of energy used to fuel
  the economy, society in your country
• Where do the major Sources of the fuel come from,
  Are they derived from inside the country?
• Has the government signed the Kyoto agreements?
  If not, can you come up with a reason?
• Are there any effects of global warming evident
  connected to the country?