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Lecture Chapter 2 - Science Matter and Energy Chapter 2 An...

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Unformatted text preview: Science, Matter, and Energy Chapter 2 An Environmental Lesson from Easter Island Dutch arrived 1722 Colonized about 2,900 years ago Soil and tree resources exhausted Over 300 statues By 1600 AD, few trees left Islanders trapped and starved War over remaining resources Key Concepts Science is a process for understanding Matter: Basic forms and resources Energy: Basic forms and resources Scientific laws governing matter and energy Physical and chemical properties Nuclear changes and radioactivity Science and Critical Thinking What is science? Scientific data Experiments Scientific hypotheses Scientific models Scientific theories Natural laws Science vs. Junk Science Scientific method Scientific results Frontier science Sound science (consensus science) Junk science Matter and its Types What is matter? Elements Compounds Chemical bonds Atoms and ions Chemical formulas Organic and inorganic compounds Atoms Subatomic particles Protons Neutrons Electrons Atomic number Mass number Isotopes Organic Compounds Hydrocarbons Chlorinated hydrocarbons Simple carbohydrates (simple sugars) Polymers and monomers Complex carbohydrates Proteins Nucleic acids (DNA and RNA) Genetic Materials Genes Chromosomes DNA Cells Organisms A human body contains trillions of cells, each with an identical set of genes. Genetic Materials 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. 2-4, p. 25 Matter Quality High-quality matter Low-quality matter Material efficiency (resource productivity) Changes in Matter Physical Chemical Chemical Reaction of Burning Carbon In text on page 26 Changes in Matter Reactant(s) carbon C + + oxygen O2 Product(s) carbon dioxide CO2 + + energy energy O C + O black solid colorless gas colorless gas O C O + energy p. 26 Law of Conservation of Matter Matter is not destroyed Matter only changes form There is no "throwing away" Matter and Pollution Chemical nature of pollutants Concentration Persistence Degradable (nonpersistent) pollutants Biodegradable pollutants Slowly degradable (persistent) pollutants Nondegradable pollutants Nuclear Change Natural radioactive decay Radioactive isotopes (radioisotopes) Half-life Radiation (alpha, beta, and gamma) Uranium-235 Uranium-235 Uranium-235 Fission fragment n Energy n Uranium-235 Nuclear (Fission) Chain Reaction Neutron n Energy n Energy n n Uranium-235 Uranium-235 Fission fragment Uranium-235 Energy Uranium-235 Uranium-235 Stepped Art Fig. 2-6, p. 28 Uranium-235 Nuclear (Fusion) Chain Reaction Fuel Proton Neutron Energy Hydrogen-2 (deuterium nucleus) + 100 million C Helium-4 nucleus + Hydrogen-3 (tritium nucleus) Reaction conditions Products + Neutron Fig. 2-7, p. 28 Nuclear Fission Critical Mass Chain Reaction Nuclear Fusion Uncontrolled Controlled Energy Definition: The ability to do "work" and transfer heat Types: kinetic and potential Electromagnetic radiation: wavelength and energy content Electromagnetic Spectrum Sun Ionizing radiation Cosmic rays Gamma rays X rays Far Near Near visible ultraviolet ultraviolet infrared waves waves waves waves 10-8 10-7 10-6 10-5 Wavelength in meters (not to scale) Nonionizing radiation Far infrared waves microwaves 10-3 TV waves Radio waves 10-14 10-12 High energy, short wavelength 10-2 10-1 1 Low energy, long wavelength Fig. 2-8, p. 29 Sunlight Energy emitted from sun (kcal/cm2/min) Visible Ultraviolet Infrared Wavelength (micrometers) Fig. 2-9, p. 30 Energy Quality Source of Energy Electricity Very high temperature heat (greater than 2,500C) Nuclear fission (uranium) Nuclear fusion (deuterium) Concentrated sunlight High-velocity wind High-temperature heat (1,0002,500C) Hydrogen gas Natural gas Gasoline Coal Food Normal sunlight Moderate-velocity wind High-velocity water flow Concentrated geothermal energy Moderate-temperature heat (1001,000C) Wood and crop wastes Relative Energy Quality (usefulness) Energy Tasks Very high-temperature heat (greater than 2,500C) for industrial processes and producing electricity to run electrical devices (lights, motors) Very high High Mechanical motion (to move vehicles and other things) High-temperature heat (1,0002,500C) for industrial processes and producing electricity Moderate Moderate-temperature heat (1001,000C) for industrial processes, cooking, producing steam, electricity, and hot water Dispersed geothermal energy Low-temperature heat (100C or lower) Low Low-temperature heat (100C or less) for space heating Fig. 2-10, p. 31 First Law of Thermodynamics Energy is not created or destroyed Energy only changes form Can't get something for nothing Energy input = Energy output Second Law of Thermodynamics In every transformation, some energy quality is lost You can't break even in terms of energy quality Second Law greatly affects life Examples of the Second Law Cars: only 20-25% gasoline produces useful energy Ordinary light bulb: 5% energy is useful light, rest is low-quality heat Living systems: quality energy lost with every conversion Second Law of Thermodynamics Solar energy Chemical energy (photosynthesis) Chemical energy (food) Waste heat Waste heat Mechanical energy (moving, thinking, living) Waste heat Waste heat Fig. 2-11, p. 32 Matter and Energy Change: Laws and Sustainability Unsustainable high-throughput (highwaste) economies Matter-recycling-and-reuse economy Sustainable low-throughput (low-waste) economies High-throughput Economies System Throughputs Inputs (from environment) High-quality energy Matter Unsustainable high-waste economy Outputs (into environment) Low-quality energy (heat) Waste and pollution Fig. 2-12, p. 33 Lessons from Nature: Lowthroughput Economy Inputs (from environment) Energy conservation Sustainable low-waste economy Matter Waste and pollution prevention Pollution control Waste and pollution System Throughputs Outputs (into environment) Low-quality energy (heat) Energy Matter Feedback Energy Feedback Recycle and reuse Fig. 2-13, p. 33 ...
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