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Science, Systems, Matter, and Energy

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1 Science, Systems, Matter, and Energy
Chapter 2 Science, Systems, Matter, and Energy Matter “High-Q” Energy “Low-Q” 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 (cont’d)
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 THE NATURE OF SCIENCE Purpose of science: What do scientists do?
Discover order in the natural world and make predictions about what is likely to happen in the future What do scientists do? Collect data. Form hypotheses. Develop theories, models and laws about how nature works. next

5 Stepped Art Ask a question Do experiments and collect data
Interpret data Well-tested and accepted patterns In data become scientific laws Formulate hypothesis to explain data Do more experiments to test hypothesis Revise hypothesis if necessary Well-tested and accepted hypotheses become scientific theories Stepped Art Fig. 2-3, p. 30

6 Scientific Theories and Laws: The Most Important Results of Science
Scientific Theory Widely tested and accepted hypothesis. Atomic Theory Scientific Law What we find happening over and over again in nature. Gravitational Constant “Peer Review” next

7 by scientific community
Research results Scientific paper Peer review by experts in field Paper rejected Peer Review Process… Paper accepted Figure 2.3 Scientists use a peer review process to help identify sound science. Paper published in scientific journal …Brutal! Research evaluated by scientific community Fig. 2-3, p. 30

8 Testing Hypotheses Scientists test hypotheses using controlled experiments and constructing mathematical models. Variables or factors influence natural processes Single-variable experiments involve a control and an experimental group. Most environmental phenomena are multivariate and are hard to control in an experiment. Models are used to analyze interactions of variables.

9 A Controlled Experiment:The Effects of Deforestation on the Loss of Water and Soil Nutrients (p.28)

10 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.

11 Frontier Science, Sound Science, and Junk Science
Reliable science a.k.a. consensus science a.k.a. sound science consists of data, theories and laws that are widely accepted by experts. Tentative science a.k.a. frontier science has not been widely tested (starting point of peer-review). Unreliable science a.k.a. junk science is presented as sound science without going through the rigors of peer-review.

12 Paradigm Shift Paradigm Shift- a complete change in worldview as a result of new information Ex Earth-centered to sun-centered view of solar system

13 Limitations of Environmental Science
Inadequate data and scientific understanding can limit and make some results controversial. Scientific testing is based on disproving rather than proving a hypothesis. Based on statistical probabilities.

Usefulness of models Complex systems are predicted by developing a model of its inputs, throughputs (flows), and outputs of matter, energy and information. Models are simplifications of “real-life”. Models can be used to predict if-then scenarios. Poorly defined models of a system result in unreliable results…models are continuously tested against new real data

15 Feedback Loops: How Systems Respond to Change
Outputs of matter, energy, or information fed back into a system can cause the system to do more or less of what it was doing. Positive feedback loop (a.k.a.reinforcing loop) causes a system to change further in the same direction (e.g. population, fighting, erosion, greed) Negative feedback loop (a.k.a. balancing loop) causes a system to change in the opposite direction (e.g. seeking shade from sun to reduce stress, hunger & eating, body temp regulation).

16 Feedback Loops: How Systems Respond to Change
Practice Positive Practice Negative Feedback Loop Feedback Loop •brother & sister yelling • hunger & eating Draw each loop and determine if it represents positive or negative feedback: • thirst & drinking •pine trees & seeds •body temperature (hot day) & sweating •bank account & interest payment •angry thought & angry feelings

17 Feedback Loops: Threshold Behavior- Negative feedback can take so long that a system reaches a tipping point and drastically changes. E.g. tipping over in a chair; the recent economic troubles; a smoker gets cancer Prolonged delays may prevent a negative feedback loop from occurring. Synergy- Processes and feedbacks in a system can interact to amplify the results. E.g. smoking exacerbates the effect of asbestos exposure on lung cancer.

18 Feedback Loops: Some negative feedback loops have explicit goals
Balancing Metersticks Body Temperature Blood CO2 levels Etc.

Elements and Compounds Matter exists in chemical forms as elements and compounds. Elements (represented on the periodic table) are the distinctive building blocks of matter. Carbon, hydrogen, oxygen, nitrogen, etc Compounds: two or more different elements held together in fixed proportions by chemical bonds. CO2, H2O, C6H12O6

20 Atoms Figure 2-4

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

22 *bases are “basic” a.k.a. “alkaline”
The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution. 0 = strongest acids 7 = neutral 14 = strongest base pH adjectives: *acids are “acidic” *bases are “basic” a.k.a. “alkaline” Figure 2-5

23 Figure 2-5

24 Compounds and Chemical Formulas
Chemical formulas are shorthand ways to show the atoms and ions in 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).

25 Organic Compounds: Carbon Rules
Organic compounds contain carbon atoms combined with one another and with various other atoms such as H+, N+, or Cl-. Organic compounds contain at least two carbon atoms combined with each other and with atoms. Methane (CH4) is the only exception. All other compounds (without C) are inorganic.

26 Organic Compounds: Carbon Rules
Hydrocarbons: compounds of carbon and hydrogen atoms (e.g. methane (CH4)). Chlorinated hydrocarbons: compounds of carbon, hydrogen, and chlorine atoms (e.g. DDT (C14H9Cl5)). Simple carbohydrates: certain types of compounds of carbon, hydrogen, and oxygen (e.g. glucose (C6H12O6)). Complex carbohydrates: chains of glucose, such as starch or cellulose

27 Cells: The Fundamental Units of Life
Cells are the basic structural and functional units of all forms of life. Prokaryotic cells (bacteria) lack a distinct nucleus. Eukaryotic cells (plants and animals) have a distinct nucleus. Figure 2-6

28 DNA (information storage, no nucleus)
(a) Prokaryotic Cell DNA (information storage, no nucleus) Figure 2.6 Natural capital: (a) generalized structure of a prokaryotic cell. Note that a prokaryotic cell lacks the distinct nucleus and generalized structure of (b) a eukaryotic cell. The parts and internal structure of cells in various types of organisms such as plants and animals differ somewhat from this generalized model. Cell membrane (transport of raw materials and finished products) Protein construction and energy conversion occur without specialized internal structures Fig. 2-6a, p. 37

29 (b) Eukaryotic Cell Nucleus (information storage) Energy conversion
Figure 2.6 Natural capital: (a) generalized structure of a prokaryotic cell. Note that a prokaryotic cell lacks the distinct nucleus and generalized structure of (b) a eukaryotic cell. The parts and internal structure of cells in various types of organisms such as plants and animals differ somewhat from this generalized model. Protein construction Cell membrane (transport of raw materials and finished products) Packaging Fig. 2-6b, p. 37

30 Macromolecules, DNA, Genes and Chromosomes
Large, complex organic molecules (macromolecules) make up the basic molecular units found in living organisms. Complex carbohydrates Proteins Nucleic acids Lipids Figure 2-7

31 Stepped Art Fig. 2-7, p. 38 A human body contains trillions
of cells, each with an identical set of genes. There is a nucleus inside each human cell (except red blood cells). Each cell nucleus has an identical set of chromosomes, which are found in pairs. A specific pair of chromosomes contains one chromosome from each parent. Each chromosome contains a long DNA molecule in the form of a coiled double helix. Genes are segments of DNA on chromosomes that contain instructions to make proteins—the building blocks of life. The genes in each cell are coded by sequences of nucleotides in their DNA molecules. Stepped Art Fig. 2-7, p. 38

32 States of Matter The atoms, ions, and molecules that make up matter are found in three physical states: solid, liquid, gaseous. 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. Scientists have made artificial plasma (used in TV screens, gas discharge lasers, florescent light).

33 Matter Quality Matter can be classified as having high or low quality depending on how useful it is to us as a resource. High quality matter is concentrated and easily extracted. low quality matter is more widely dispersed and more difficult to extract. Figure 2-8

34 Coal-fired power plant emissions
High Quality Low Quality Solid Gas Salt Solution of salt in water Coal Coal-fired power plant emissions Figure 2.8 Examples of differences in matter quality. High-quality matter (left column) is fairly easy to extract and is concentrated; low-quality matter (right column) is more difficult to extract and is more widely dispersed than high-quality matter. Gasoline Automobile emissions Aluminum can Aluminum ore Fig. 2-8, p. 39

35 CHANGES IN MATTER Matter can change from one physical form to another or change its chemical composition. When a physical or chemical change occurs, no atoms are created or destroyed. 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. Chemical equations are used to represent the reaction.

36 Chemical Change Energy is given off during the reaction as a product.
Mass does not change (Conservation of Matter)

37 Three Types of Atomic Nuclear Changes
Radioactive decay Fission- splitting atoms (like uranium) First atomic bombs All nuclear power plants Fusion- fusing atoms together (like hydrogen) “H-Bomb” Sun and all other stars 100 million degrees Celsius to begin reaction

38 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

39 Stepped Art Fig. 2-6, p. 28 Uranium-235 Energy Fission fragment n
Neutron Stepped Art Fig. 2-6, p. 28

40 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

41 Reaction Conditions Products Fuel Proton Neutron Energy Hydrogen-2
(deuterium nucleus) + 100 million °C + Figure 2.10 The deuterium–tritium (D–T) nuclear fusion reaction takes place at extremely high temperatures. Helium-4 nucleus + + Hydrogen-3 (tritium nucleus) Neutron Fig. 2-10, p. 42

42 Nuclear Changes: Radioactive Decay
Natural radioactive decay: unstable isotopes spontaneously emit fast moving chunks of matter (alpha or beta particles), high-energy radiation (gamma rays), or both at a fixed rate. 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).

43 Matter: Types of Pollutants
Factors that determine the severity of a pollutant’s effects: chemical nature, concentration, and persistence. Pollutants are classified based on their persistence: Degradable pollutants- can be broken down Biodegradable pollutants- e.g. human sewage Slowly degradable pollutants- e.g. most plastics; chlorinated hydrocarbons like DDT Nondegradable (a.k.a. persistent) pollutants- e.g. lead, mercury, arsenic

44 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, any food, water behind a dam

45 Electromagnetic Spectrum
Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content. Next

46 Sun Ionizing radiation Nonionizing radiation Cosmic rays Gamma Rays
Far ultra- violet waves Near ultra- violet waves Near infrared waves Far infrared waves Cosmic rays Gamma Rays X rays Visible Waves Micro- waves TV waves Radio Waves Figure 2.11 The electromagnetic spectrum: the range of electromagnetic waves, which differ in wavelength (distance between successive peaks or troughs) and energy content. High energy, short Wavelength Wavelength in meters (not to scale) Low energy, long Wavelength

47 Electromagnetic Spectrum
Organisms vary in their ability to sense different parts of the spectrum. Next

48 Energy emitted from sun (kcal/cm2/min)
Visible Figure 2.12 Solar capital: the spectrum of electromagnetic radiation released by the sun consists mostly of visible light. Infrared Ultraviolet Wavelength (micrometers) Fig. 2-12, p. 43

49 Source of Energy Energy Tasks Relative Energy Quality (usefulness)
Electricity Very high temperature heat (greater than 2,500°C) Nuclear fission (uranium) Nuclear fusion (deuterium) Concentrated sunlight High-velocity wind Very high-temperature heat (greater than 2,500°C) for industrial processes and producing electricity to run electrical devices (lights, motors) High-temperature heat (1,000–2,500°C) Hydrogen gas Natural gas Gasoline Coal Food Mechanical motion to move vehicles and other things) High-temperature heat (1,000–2,500°C) for industrial processes and producing electricity Normal sunlight Moderate-velocity wind High-velocity water flow Concentrated geothermal energy Moderate-temperature heat (100–1,000°C) Wood and crop wastes Moderate-temperature heat (100–1,000°C) for industrial processes, cooking, producing steam, electricity, and hot water Figure 2.13 Natural capital: categories of the qualities of different sources of energy. High-quality energy is concentrated and has great ability to perform useful work. Low-quality energy is dispersed and has little ability to do useful work. To avoid unnecessary energy waste, you should match the quality of an energy source with the quality of energy needed to perform a task. Dispersed geothermal energy Low-temperature heat (100°C or lower) Low-temperature heat (100°C or less) for space heating Fig. 2-13, p. 44

The first law of thermodynamics: we cannot create or destroy energy (a.k.a. Law of Conservation of Energy) We can change energy from one form to another. burning Cheeto: Chemical→ thermal & electromagnetic The second law of thermodynamics: energy quality always decreases (a.k.a. Law of Entropy) 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.

51 Mechanical energy (moving, thinking, living)
Second Law of Thermodynamics Mechanical energy (moving, thinking, living) Chemical energy (photosynthesis) Chemical energy (food) Solar energy Waste Heat Waste Heat Waste Heat Waste Heat Figure 2.14 The second law of thermodynamics in action in living systems. Each time energy changes from one form to another, some of the initial input of high-quality energy is degraded, usually to low-quality heat that is dispersed into the environment. Fig. 2-14, p. 45

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

53 Throughputs Inputs Outputs
System Throughputs Inputs (from environment) Outputs (into environment) High-quality energy Unsustainable high-waste economy Low-quality energy (heat) Matter Waste and pollution Figure 2.15 The high-throughput economies of most developed countries rely on continually increasing the rates of energy and matter flow. This practice produces valuable goods and services but also converts high-quality matter and energy resources into waste, pollution, and low-quality heat. Fig. 2-15, p. 46

54 Energy Inputs Throughputs Outputs Energy resources Heat Matter
Waste and pollution Economy Figure 2.10 Inputs, throughput, and outputs of an economic system. Such systems depend on inputs of matter and energy resources and outputs of waste and heat to the environment. Such a system can become unsustainable if the throughput of matter and energy resources exceeds the ability of the earth’s natural capital to provide the required resource inputs or the ability of the environment to assimilate or dilute the resulting heat, pollution, and environmental degradation. Goods and services Information Fig. 2-10, p. 44

55 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. Why not? Only sustainable if population stabilizes (ZPG)!

56 Figure 2.11 Positive feedback loop. Decreasing vegetation in a valley causes increasing erosion and nutrient losses, which in turn causes more vegetation to die, which allows for more erosion and nutrient losses. The system receives feedback that continues the process of deforestation. Fig. 2-11, p. 45

57 Figure 2.12 Negative feedback loop. When a house being heated by a furnace gets to a certain temperature, its thermostat is set to turn off the furnace, and the house begins to cool instead of continuing to get warmer. When the house temperature drops below the set point, this information is fed back, and the furnace is turned on and runs until the desired temperature is reached. The system receives feedback that reverses the process of heating or cooling. Fig. 2-12, p. 45

58 Data Analysis Marine scientists from the U.S. state of Maryland have produced the following two graphs as part of a report on the current health of the Chesapeake Bay. They are pleased with the recovery of the striped bass population but are concerned about the decline of the blue crab population, because blue crabs are consumed by mature striped bass. Their hypothesis is that as the population of striped bass increases, the population of blue crab decreases. p. 49

59 Data Analysis Marine scientists from the U.S. state of Maryland have produced the following two graphs as part of a report on the current health of the Chesapeake Bay. They are pleased with the recovery of the striped bass population but are concerned about the decline of the blue crab population, because blue crabs are consumed by mature striped bass. Their hypothesis is that as the population of striped bass increases, the population of blue crab decreases. p. 49

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