Science, Systems, Matter, and Energy

1
Chapter 2

• Science, Systems, Matter, and Energy

2
Chapter Overview Questions

• What is science, and what do scientists do?
• What are major components and behaviors of
  complex systems?
• What are the basic forms of matter, and what
  makes matter useful as a resource?
• What types of changes can matter undergo and what
  scientific law governs matter?

3
Chapter Overview Questions (contd)

• What are the major forms of energy, and what
  makes energy useful as a resource?
• What are two scientific laws governing changes of
  energy from one form to another?
• How are the scientific laws governing changes of
  matter and energy from one form to another
  related to resource use, environmental
  degradation and sustainability?

4
(No Transcript)
5
THE NATURE OF SCIENCE

• What do scientists do?
• Collect data.
• Form hypotheses.
• Develop theories, models and laws about how
  nature works.

Figure 2-2
6
Scientific Theories and Laws The Most Important
Results of Science

• Scientific Theory
• Widely tested and accepted hypothesis, often
  explains why or how.
• Scientific Law
• What we find happening over and over again in
  nature, often explains what.

Figure 2-3
7
Testing Hypotheses

• Scientists test hypotheses using controlled
  experiments and constructing mathematical models.
• Variables or factors influence natural processes
• Models are used to analyze interactions of
  variables.

8
Scientific Reasoning and Creativity

• Inductive reasoning
• Involves using specific observations and
  measurements to arrive at a general conclusion or
  hypothesis.
• Bottom-up reasoning going from specific to
  general.
• Deductive reasoning
• Uses logic to arrive at a specific conclusion.
• Top-down approach that goes from general to
  specific.

9
Frontier Science, Sound Science, and Junk Science

• 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.

10
MODELS AND BEHAVIOR OF SYSTEMS

• Usefulness of models
• Complex systems are predicted by developing a
  model
• Models are simplifications of real-life.
• Models can be used to predict if-then scenarios.

11
Feedback Loops How Systems Respond to Change

• 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).

12
Animation Feedback Control of Temperature
PLAY ANIMATION
13
Feedback Loops

• 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.

14
TYPES AND STRUCTURE OF MATTER

• Matter exists in chemical forms as elements and
  compounds.
• Elements (represented on the periodic table)
  identified by their number of protons.
• Compounds two or more different elements held
  together by chemical bonds.

15
Atoms
Figure 2-4
16
Animation Subatomic Particles
PLAY ANIMATION
17
Animation Atomic Number, Mass Number
PLAY ANIMATION
18
Ions

• An ion is an atom or group of atoms with one or
  more net positive or negative charges.
• The number of positive or negative charges on an
  ion is shown as a superscript
• Hydrogen ions (H), Hydroxide ions (OH-)
• Sodium ions (Na), Chloride ions (Cl-)

19
Animation Ionic Bonds
PLAY ANIMATION
20

• The pH (potential of Hydrogen) is the
  concentration of hydrogen ions in one liter of
  solution.

Figure 2-5
21
Animation pH Scale
PLAY ANIMATION
22
Compounds and Chemical Formulas

• Chemical formulas are shorthand ways to show 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).

23
Cells The Fundamental Units of Life

• Prokaryotic cells (bacteria) lack a distinct
  nucleus.
• Eukaryotic cells (plants and animals) have a
  distinct nucleus.

Figure 2-6
24
(a) Prokaryotic Cell
DNA(information storage, no nucleus)
Cell membrane (transport of raw materials and
finished products)
Protein construction and energy conversion occur
without specialized internal structures
Fig. 2-6a, p. 37
25
(b) Eukaryotic Cell
Energy conversion
Nucleus (information storage)
Protein construction
Cell membrane (transport of raw materials
and finished products)
Packaging
Fig. 2-6b, p. 37
26
Animation Prokaryotic and Eukaryotic Cells
PLAY ANIMATION
27
States of Matter

• 3 solid, liquid, gas
• 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.

28
Matter Quality

• High quality matter is concentrated and easily
  extracted.
• Low quality matter is more widely dispersed and
  more difficult to extract.

Figure 2-8
29
High Quality
Low Quality
Solid
Gas
Solution of salt in water
Salt
Coal
Coal-fired power plant emissions
Gasoline
Automobile emissions
Aluminum can
Aluminum ore
Fig. 2-8, p. 39
30
CHANGES IN MATTER

• 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.

31
Chemical Change

• Energy is given off during the reaction as a
  product.

32
Types of Pollutants

• Factors that determine the severity of a
  pollutants effects chemical nature,
  concentration, and persistence.
• Degradable pollutants
• Biodegradable pollutants
• Slowly degradable pollutants
• Nondegradable pollutants

33
Nuclear Changes Radioactive Decay

• Natural radioactive decay unstable isotopes
  spontaneously emit fast moving chunks of matter
• 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).

34
Animation Positron-Emission Tomography
PLAY ANIMATION
35
Animation Half-Life
PLAY ANIMATION
36
Nuclear Changes Fission

• Nuclear fission nuclei of certain isotopes with
  large mass numbers are split apart into lighter
  nuclei when struck by neutrons.

Figure 2-9
37
Stepped Art
Fig. 2-6, p. 28
38
Video Isotopes
PLAY VIDEO
39
Nuclear Changes Fusion

• Nuclear fusion two isotopes of light elements
  are forced together at extremely high
  temperatures until they fuse to form a heavier
  nucleus.

Figure 2-10
40
Reaction Conditions
Products
Fuel
Proton
Neutron
Energy
Hydrogen-2 (deuterium nucleus)

100 million C

Helium-4 nucleus


Hydrogen-3 (tritium nucleus)
Neutron
Fig. 2-10, p. 42
41
Video Nuclear Energy
PLAY VIDEO

• From ABC News, Environmental Science in the
  Headlines, 2005 DVD.

42
ENERGY

• 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

43
Animation Martian Doing Mechanical Work
PLAY ANIMATION
44
Electromagnetic Spectrum

• Many different forms of electromagnetic radiation
  exist, each having a different wavelength and
  energy content.

Figure 2-11
45
Animation Visible Light
PLAY ANIMATION
46
ENERGY LAWS TWO RULES WE CANNOT BREAK

• 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.

47
Animation Total Energy Remains Constant
PLAY ANIMATION
48
Recycling of energy in the Environment
Mechanicalenergy(moving,thinking,living)
Chemical energy (photosynthesis)
Chemical energy (food)
Solar energy
Waste Heat
Waste Heat
Waste Heat
Waste Heat
Fig. 2-14, p. 45
49
Animation Energy Flow
PLAY ANIMATION
50
SUSTAINABILITY AND MATTER AND ENERGY LAWS

• Unsustainable High-Throughput Economies Working
  in Straight Lines
• Converts resources to goods in a manner that
  promotes waste and pollution.

Figure 2-15
51
Sustainable Low-Throughput Economies Learning
from Nature

• Matter-Recycling-and-Reuse Economies Working in
  Circles
• Mimics nature by recycling and reusing, thus
  reducing pollutants and waste.
• It is not sustainable for growing populations.

52
Inputs (from environment)
System Throughputs
Outputs (into environment)
Energy conservation
Low-quality Energy (heat)
Energy
Sustainable low-waste economy
Waste and pollution
Waste and pollution
Pollution control
Matter
Recycle and reuse
Matter Feedback
Energy Feedback
Fig. 2-16, p. 47
53
Animation Economic Types
PLAY ANIMATION