Science. Matter. Energy. Systems.

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Science. Matter. Energy. Systems.

• Chapter 2

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Important Definitions to Review

• Science knowledge of how the world works
• Technology creation of new processes intended
  to improve the quality of life
• Law certain phenomena always act in a
  predictable manner
• Theory rational explanation for numerous
  observations of a certain phenomena global
  warming due to greenhouse effect
• Accuracy measurement agrees with the accepted
  correct value
• Precision measure of reproducibility
• Inductive reasoning- using observations and facts
  to arrive at generalizations
• Deductive reasoning - using logic to arrive at a
  specific conclusion

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Scientific method

• identify question/problem
• HYPOTHESIS proposed to explain observed
  patterns
• Complete experiment and collect data
• Analysis and conclusions (results tentative,
  reliable or unreliable)
• Experiments subject to peer review
• identify biases
• Identify limitations

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Systems

• system set of components that interact in some
  regular way
• Open system systems the exchange both energy and
  matter across their boundaries
• most environmental systems open
• Inputs - matter, energy, information
• Throughput - flow of input
• Output - matter, energy, information flowing out
• Closed system exchange energy but not matter
  across their boundaries
• ex. water cycle
• feedback loop Change in one part of a system
  influences another part of the system

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Positive feedback loop

• causes a system to change further in the same
  direction. (farther from normal)
• Exponential growth of population more
  individuals lead to increased number of births
• Precipitation causes erosion. Erosion causes
  plants to die. More precipitation causes more
  erosion and more vegetation death.

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Negative feedback loop

• system to change in the opposite direction from
  which it is moving (closer to normal)
• Temperature regulation in humans increased
  temperature leads to decrease in temperature by
  sweating

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Implications for the environment High waste
society
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Implications for the environment Low waste
society
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Complex systems

• Time lags change in a system leads to other
  changes after a delay
• lung cancer
• Resistance to change built in resistance
• political, economic
• Synergy-when two or more processes interact so
  that the combined effect is greater
• Can be beneficial or harmful
• Chaos unpredictable behavior in a system

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Matter and Energy Resources

• Natures Building Blocks
• anything that has mass and takes up space

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Forms of matter

• elements single type of atoms
• 110 elements
• 92 natural, 18 synthesized
• table 2.1 (important elements)
• compounds - 2 or more elements, held together by
  chemical bonds
• table 2.3 (important compounds)

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Atomic Theory Definitions

• atoms - smallest units of matter- protons (),
  neutrons (0), electrons (-)
• protons/neutrons in nucleus of atom
• atomic of protons
• isotope same atomic number but different mass
  number (different form of the same element)
• Carbon-14 Uranium-235
• ion - electrically charged atoms
• Table 2.2 (important ions)
• molecules - combinations of atoms of the same or
  different elements

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Some Important elements composition by weight
only 8 elements make up 98.5 of the Earths crust
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Organic Compounds

• with 2 or more atoms of carbon
• hydrocarbons carbon and hydrogen atoms
• methane CH4 (only exception to 2 C rule)
• Octane C8H18
• chlorinated hydrocarbons carbon, hydrogen and
  chlorine
• DDT C14H9Cl5
• Simple carbohydrates carbon, hydrogen and oxygen
• glucose C6H12O6
• Also includes Polymers.
• complex carbohydrates (made of simple sugars),
  nucleic acids (made of nucleotides), proteins
  (made of amino acids) and lipids

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Inorganic compounds

• no carbon, not originating from a living source
• Earths crust minerals, water
• water, nitrous oxide, nitric oxide, sodium
  chloride, ammonia

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Matter quality

• Measure of how useful a matter is for humans
  based on availability and concentration

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Energy

• capacity to do work and transfer heat
• Kinetic Energy -energy in action
• electromagnetic radiation (energy in waves
  resulting from electrical/magnetic fields), heat
  (energy in moving atoms)
• Potential energy - stored energy that is
  potentially available may be changed to kinetic

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Electromagnetic radiation

• different wave lengths
• Shorter wavelength high energy
• disrupts cells with long term exposure

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Energy sources

• 99 of the energy that supports earth comes from
  the sun
• without it earths temperature -240 C or -400 F
• allows for wind, hydro and biomass sources of
  renewable energy
• 1 - commercial sources. Burning oil, coal and
  natural gas.

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Energy quality

• Measure of how useful an energy source is in
  terms of concentration and ability to perform
  useful work

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Energy Changes

• energy changes governed by 2 scientific laws
• law of conservation of energy (first law of
  thermodynamics)
• no energy is created or destroyed as it changes
  from one form to another
• energy input energy output
• can lose energy quality (converted to a less
  useful form)
• second law of thermodynamics
• as energy changes form we end up with a lower
  quality or less usable energy source (heat)

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Nuclear Changes

• nuclei of certain isotopes spontaneously change
  (radioisotopes) or made to change into one or
  more different isotopes
• Occurs with one of the following particles
• Alpha particles fast moving (2 protons2
  neutrons)
• Beta particles high speed electrons
• Gamma particles - high energy electromagnetic
  radiation
• radioactive decay, nuclear fission, nuclear
  fusion

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Use.radioisotopes

• Estimate age of rocks and fossils
• Tracers in pollution detection and medicine
• Genetic control of insects

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Half Life (radioactive decay)

• time needed for one-half of the nuclei in a
  radioisotope to decay and emit their radiation.
• ranges from fraction of a second to millions of
  years

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Nuclear Fission

• certain isotopes (uranium-235) split apart into
  lighter nuclei neutrons when struck by neutrons
• chain reaction releases energy
• Releases an enormous amount of energy very quickly

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Nuclear fusion

• two isotopes (hydrogen) forced together at
  extremely high temperatures (100 million C)
• Fuse to form a heavy nucleus and release a
  tremendous amount of energy

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