Biology ch. 7-12

1.) Contrast health issues in highly developed countries with those in less developed countries.
Developed countries: Cardiovascular diseases, cancer, and chronic obstructive pulmonary disease- health problems in the United States and highly developed nations
-Premature deaths caused by lifestyle choices involving diet, exercise, and smoking.
Developing Countries: Child mortality is particularly serious in developing countries, where leading causes of death in children include malnutrition, diarrheal diseases, and malaria.
2.) Explain the difference between endemic and emerging diseases.
Endemic diseases: are constantly present in a population or region. Some endemic diseases, such as smallpox and polio, have been controlled world- wide, while others remain common.
Emerging diseases: relatively new to human populations. Usually jumps from animal host. Because different strains prevail each year, influenza is often thought of as an emerging disease. AIDS was an emerging disease a few decades ago, but is now endemic in many places.
*WHO global vaccination project 1988-reduced incidence.
3.) Summarize the problems associated with chemicals that exhibit persistence, bioaccumulation, and biological magnification in the environment.
Chemicals that exhibit persistence are extremely stable and may take many years to break down into simpler forms by natural processes. Chemicals not found in nature. (DDT).
Bioaccumulation (Bioconcentrate): buildup of a persistent toxic substance (certain pesticides) in an organism’s body, often in fatty tissues.
Biological magnification: increased concentration of toxic chemicals, (Like PCBs, heavy metals, certain pesticides) in the tissues of organisms at higher levels in food webs.
4.) Briefly describe some of the data suggesting that certain chemicals used by humans may also function as endocrine disrupters in animals, including humans.
A chemical spill in 1980 contaminated Lake Apopka, FL with DDT and other agricultural chemicals with estrogenic properties. Male alligators living in Lake Apopka had low levels of testosterone (an androgen) and elevated levels of estrogen. Their reproductive organs were often feminized or abnormally small, and the mortality rate for eggs was extremely high. Humans may also be at risk from endocrine disrupters, as the number of reproductive disorders, infertility cases, and hormonally related cancers (such as testicular cancer and breast cancer) appears to be increasing. Phthalates- potential disrupter
5.) Define toxicant,and distinguish between acute and chronic toxicities.
Toxicant: a chemical with adverse human health effects. Measured-dose/response
Acute toxicity: adverse effects occur within a short period after exposure to toxin.
Chronic toxicity: adverse effects occur some time after exposure, or after prolonged exposure to toxin.
*Epidemiology: study of effects of toxic chemicals & diseases on human populations.
6.) Describe how a dose-response curve helps determine the health effects of environmental pollutants.
Dose-response curve: graph-shows effect of different doses on a population. Scientists first test the effects of high doses and then work their way down to a threshold level.
7.) Discuss pesticide risks to children.
1/2^ of all exposure reports & possible poisoning from household pesticides involve children. Exposure to pesticides may affect the development of intelligence & motor skills of infants-preschoolers
8.) Discuss how discovery of the effects of DDT on birds led to the replacement of the dilution paradigm with the boomerang paradigm.
Paradigm:generally accepted understanding- some aspect of the world works. According to the dilution paradigm(not valid), “solution to pollution-dilution.” Envi. scientists reject dilution paradigm for boomerang paradigm: “What you throw away can come back & hurt you.” Boomerang paradigm-after discovery that pesticide DDT- accumulating in birds at the top of the food web. Implications- DDT represented unacceptable threat to ecosystem & human health.
9.) Define ecotoxicology, and explain why knowledge of ecotoxicology is essential to human well-being.
Ecotoxicology: study of contaminants in biosphere & their harmful effects on ecosystems. Ecotoxicology helps policy makers determine costs/benefits of many industrial & technological “advances” that affect us & ecosystems we depend on. *Toxic Substances Control Act 1976
10.) Define risk, and explain how risk assessment helps determine adverse health effects.
Risk: probability that a particular adverse effect will result from some exposure or condition. Risk assessment: estimating/provide info about those probabilities and consequences. Assess risk 4 steps: Hazard identification, Dose response, Exposure assessment, Risk characterization.
11.) Explain how risk information can improve environmental decisions.
Risk information- used to inform different decision approaches. Risk management: risks are assessed/described & policy choices are chosen to reduce known risks. Risk- input to cost-benefit analysis. Precautionary principle: No action taken when science inconclusive but risks are unknown. Fractional risk attribution: allocate responsibility for adverse outcomes based on likely contributors to those outcomes, even when cause of individual cases can’t be determined.
12.) Define ecological risk assessment.
Ecological risk assessment: Process- ecological consequences of a range of human-induced stressors are estimated. Difficult to assess b/c effect occur at wide range of scales: individual plants/animals-ecological communities over wide regions.
1.) Define demography and summarize the history of human population growth.
Demography: branch of sociology that studies population statistics, structure & growth. Thousands of yrs- human population to reach 1 billion. 130 yrs-2 bill (1930). 30 yrs-3 bill (1960). 15 yrs-4 bill (1975). 12 yrs-5 bill (1987). 12 yrs-6 bill (1999). 12 yrs-7 bill (2011). World population increase(decreased death); world growth rate (r)-declined since mid-1960s till 0 population growth
2.) Identify Thomas Malthus, relate his ideas on human population growth, and explain why he might or might not be correct.
Thomas Malthus: 19th-century economist-human population could increase faster than food supply(famine, disease, war). Wrong b/c: scientific advances allowed food production to keep pace with population growth. Correct b/c: we don’t know if increase food production is sustainable.
3.) Explain why it is impossible to answer precisely how many people Earth can support—that is, Earth’s carrying capacity for humans.
Carrying capacity(K): max # of individuals of a species that a particular environment can support for indefinite period, assuming no changes in environment. Estimates of # of people Earth can support vary b/c different standard of living, resource consumption, technological innovations & waste generation. If High lvl of material well-being=lifestyles in high developed countries, then Earth supports less humans.
4.) Explain how highly developed and developing countries differ in population characteristics such as infant mortality rate, total fertility rate, and age structure.
Infant mortality rate: # of infant deaths (under age 1) per 1000 live births.
Total fertility rate (TFR): average # of kids born to each woman.
Age structure: # & proportion of people at each age in a population.
Highly developed countries: lowest infant mortality rates, lowest total fertility rates & oldest age structure. Developing countries: highest infant mortality rates, highest total fertility rates & youngest age structure.Low fertility rate-large elderly population
5.) Explain how population growth momentum works.
Population growth momentum: potential future increases/decreases in a population based on present age structure. Country can have replacement-lvl fertility & still experience population growth if the largest percentage of the population is in prereproductive years.
6.) Relate carrying capacity to agricultural productivity.
land overuse occurs, often combined with extended drought, productive lands decline in agricultural productivity. Carrying capacity decrease.
7.) Relate human population to chronic hunger and food insecurity.
Rapid increased population-many human problems: hunger. Food insecurity: people live with chronic hunger/malnutrition. Weakened immune system, illness/disease. Countries with greatest food shortages-highest TFRs.
8.) Describe the relationship between economic development and population growth.
Economic development: expansion in government’s economy-best way to raise standard of living. Economists think slowing population growth promotes economic development.
9.) Define culture and explain how total fertility rate and cultural values are related.
Culture: ideas/customs of a group of people at a given period-passed generation to generation-evolves over time. 4 factors responsible for high TFRs: high infant/child mortality rates(children in demand), important economic/societal roles of children(Fam business), women-low status, lacking health/family planning services.
10.) Define gender inequality and relate the social and economic status of women to total fertility rate.
Gender inequality: social construct-women not having same rights, opportunities, privileges as men. Most important factor affecting high TFRs.
11.) Explain how the availability of family planning services affects total fertility rate.
Family planning services: enable men/women to limit family size, safeguard individual health rights, improve quality of life. TFRs-decrease when family planning services available.
12.) Compare how the governments of China and Mexico have tried to slow human population growth.
China 1979: coercive 1-child family/later marriage incentive policy-reduce TFR. Program now relaxed in rural China; education/publicity campaigns used today. Mexico 1974: government instigated educational reform, family planning, healthcare. Recent effort: multimedia campaigns.
13.) Explain the role of population growth momentum in Mexico’s population growth.
Even with lower birth rates, Mexico’s positive population growth momentum will cause its population to increase because of the large number of young women having babies.
14.) Describe at least four of the millennium Development goals that came out of the UN Millennium Summit.
Millennium Development Goals (MDGs): eradicate extreme hunger/poverty; achieve universal primary education; promote gender equality/empower women; reduce child mortality; improve maternal health; combat HIV/AIDS, malaria/other diseases; ensure environmental sustainability; develop global partnership for economic development.
15.) Explain how individuals can adopt voluntary simplicity to miti- gate the effects of population growth.
Voluntary simplicity: way of life involving wanting/spending less. Each person who scales back unnecessary consumption lessens effects of population growth.
1.) urbanization:
Process-people increasingly move from rural areas to densely populated cities. Urbanization is growing more quickly in developing countries than in developed countries.
Describe trends in the distribution of people in rural and urban areas:
As a nation develops economically, the proportion of the population living in cities increases. In developing nations, most people live in rural settings, but their rates of urbanization are rapidly increasing.
Jobs define urban vs. rural, not populations
The young age structure of urban areas can be attributed to influx of young people from rural areas.
2.) Distinguish between megacities and urban agglomerations:
Megacities: Cities with more that 10 million inhabitants. CITIES> 10 Million inhabitants
In some places, separate urban areas have merged into an:
Urban agglomeration: urbanized core region that consists of several adjacent cities or megacities and their surrounding developed suburbs.
3.) Describe some of the problems associated with the rapid growth rates of large urban areas.
Rapid urban growth often outstrips the capacity of cities to provide basic services. Challenges include substandard housing; poverty; high unemployment; pollution; and inadequate or nonexistent water, sewage, waste disposal, police and fire protection. *? urban population in developing countries=squatters.
Rapid urban growth also strains school, medical, and transportation systems. Cities in less developed nations are generally faced with more serious challenges than are cities in highly developed countries.
4.) Explain how cities are analyzed from an ecosystem perspective.
Urban ecosystem: an urban area studied in the context of a broader ecological system.
Urban ecology: is the study of urban trends and patterns in the context of four interrelated variables: population, organization, environment, and technology (POET).
Population- total number of people: births, deaths, immigration and emigration and the composition of the city by age, sex, and ethnicity.
Organization- social structure of the city, including its economic policies, method of government, and social hierarchy.
Environment- includes both the natural environment and they city’s physical infrastructure (man made), including its roads, bridges, and buildings. Including changes like: air and water pollution.
Technology- human inventions that directly affects the urban environment. (aqueducts, air conditioning etc.)
5.) Describe brownfields and food deserts:
Brownfield: an urban area of abandoned, vacant factories, warehouses, and residential sites that may be contaminated from part uses.
Food desert: an area where grocery stores and farmers’ markets are not as abundant as fast food and convenience stores. Typically, high processed foods are easier to purchase than fresh produce in these neighborhoods.
6.) distinguish between urban heat islands and dust domes:
Urban heat island: local heat buildup in an area of high population density. Affect local air currents and weather conditions. Contribute to buildup of pollutants-dust domes.
Dust dome: dome of heated air that surrounds an urban area and contains a lot of air pollution.
7.) Define Compact development (Environmental benefits of urbanization):
The designs of cities in which tall, multiple-unit residential buildings are close to shopping and jobs, and all are connected by public transportation.
designing and constructing buildings that are energy efficient, economical, and made of recycled materials, is a trend called: green architecture.
8.) Discuss the use of zoning in land-use planning:
Land-use planning: process of deciding the best uses for undeveloped land in a given area. (David Harvey 1970s and Baltimore, Maryland)
The main way that cities regulate land use is by zoning, in which the city is divided into use zones.
Use zones: areas restricted to specific land uses, such as commercial, residential, or industrial. Zoning has largely resulted in separation of industrial parks, shopping centers, apartment districts, and other land uses. Property owners must meet zoning ordinances.
9.) Relate how a city’s transportation infrastructure affects urban development:
Transportation and land use are linked, because as cities grow, they expand along public transportation routes. Cars and trucks have increased the city’s spatial scale: The interstate highway system and beltway “loops” have encouraged development far from city’s central business district.
10.) Define suburban sprawl and discuss a problem caused or exacerbated by sprawl:
Suburban sprawl: patchwork of vacant and developed tracts around the edges of cities; sprawl contains a low population density.
Sprawl cuts into the surrounding rural land and causes environmental problems such as loss of wetlands, loss of biological habitat, air and water pollution.
11.) List at least 5 characteristics of an ideal sustainable city:
Sustainable city: a city with a livable environment, a strong economy, and a social and cultural sense of community; sustainable cities enhance the wellbeing of current and future generations of urban dwellers.
A sustainable city has clear, cohesive urban policies that enable the government infrastructure to manage it effectively.
Uses energy and other resources efficiently and makes use of renewable energy as much as possible.
Reduces pollution and wastes by reusing and recycling materials.
Has large areas of green space.
People-centered, not automobile-centered.
-sustainable urban development I really involves: green space, recycling, urban farmers, solar energy.
12.) Explain how city planners have incorporated environmental sustainability into the design of Curitiba, Brazil:
Curitiba developed an inexpensive, efficient mass transit system that uses clean, modern buses that run in high-speed bus lanes. High-density development was largely restricted to areas along the bus lines. Curitiba uses a special low-polluting fuel that contains a mixture of diesel fuel, alcohol, and soybean extract. Over several decades, Curitiba purchased and converted flood-prone properties along rivers in the city to a series of interconnected parks crisscrossed by bicycle paths. This move reduced flood damage and increased the per capita amount of green space.
Biophilic design:
based on the theory of ‘biophilia’ which contends that human health and well-being has a biologically based need to affiliate with nature.
13.) Explain the importance of the concentration of energy in a source:
The concentration of energy in a source determines the amount of useful energy that can be extracted from a given volume or mass of fuel. Concentrated fuels are typically easier to transport and use than are less concentrated fuels. Modern transportation, industry, agriculture, and buildings rely on highly concentrated fuels like coal and gasoline.
14.) Describe global energy use:
Energy use is unevenly distributed around the world. 20% of the world’s population uses 60% of all commercial energy. Global energy use has increased every year for several decades. Some highly developed countries have managed to keep their energy use constant over the past decade. Energy use in China and India is growing rapidly, although per capita energy use in those countries remains below that of highly developed countries like the United States.
15.) Explain the relationship between energy services and efficiency:
Energy services: the benefits we get from using energy. They include transportation, industry, agriculture, commercial, and household energy use.
Energy efficiency: using less energy to accomplish a given task, as for example, with new technology. Amount of available energy in a source that is transformed into useful work.(NAECA sets national standards for appliances [2010])
changing incandescent light bulbs to compact fluorescent light bulbs will increase energy efficiency.
Light bulbs ranked from most to least efficient: LED>compact fluorescent>incandescent
Energy conservation: Using less energy, as for an example, by reducing energy use and waste.
More efficient practices and technologies allow us to get more energy services from a given amount of an energy resource.
16.) Describe some advantages and disadvantages of conserving energy:
Energy conservation: saves money, reduces pollution, and reduces our reliance on foreign energy sources.
Some forms of conservation, such as maintaining a lower indoor temperature in winter, are seen by some as reducing the quality of life.
Other conservation measures, such as switching from driving to walking, can have both benefits (health, cost savings) and downsides (longer commute time).
compared to development of new energy sources, energy efficiency and energy conservation costs less, improves the economy’s productivity, and saves energy for future uses.
Why is investment in energy conservation and efficiency a necessary component of any governmental energy policy? —it is often difficult for individuals or corporations to make purchases that save money in the long run, if they are more expensive over the short term.
17.) Explain why electricity is a flexible form of energy:
Electricity: the flow of electrons in a wire. Can be produced from any energy resource.
-It is relatively easy to transport and can be used in very small or very large amounts.
-Finally, it can be put to a range of uses, from heating and lighting to electronics to transportation.
-Source of electricity can be 100s of miles away. Environmental impacts are far away from those who use the energy.
18.) Provide examples of the role hydrogen could play as a future fuel source:
Hydrogen can be generated from a variety of energy sources and can be used for transportation as either a combustible fuel or in a fuel cell.
Consequently, hydrogen has the potential to serve as a major transportation energy source if we transition away from fossil fuels.
Hydrogen can also be used to store energy.
Hydrogen Fuel cell: device that directly converts chemical energy into electricity.
19.) Describe the advantages and disadvantages of storing energy:
Energy resources are not always available when we need them. Because of this mismatch between the timing of energy production and consumption, it can be useful to store energy when it is produced and release it as demand increases. Most energy storage technologies, however, are inefficient- that in each time energy is stored and released, less of it is available for use. Energy storage technologies take advantage of potential, thermal, chemical, electrochemical, and kinetic energy, as well as superconducting magnets.
20.) Discuss how policy decisions shape energy resource and technology development:
Energy policy decisions can encourage or discourage particular energy resources, both through subsidizing the development of some sources but not others and through funding research to develop future energy sources. Policy decisions can influence which technologies get used. Minimum vehicle fuel-efficiency standards promote conservation. Planning that focuses on building large, unimpeded roadways promotes car ownership.
Objective 1: Increase Energy Efficiency and Conservation
-Requires many unpopular decisions
-Examples:
-Decrease speed limit to conserve fuel
-Eliminate government subsidies
Objective 2: Secure Future Fossil Fuel Energy Supplies
-2 oppositions: environmental and economic
Objective 3: Develop Alternative Energy Sources
-Who should pay for this? Gas taxes?
Objective 4: Meet the First Three Objectives Without Further Damage to the Environment
-Tax per barrel?
1.) Define fossil fuel and distinguish among coal, oil, and natural gas.
Fossil fuels are combustible deposits in Earth’s crust, composed of the remnants of prehistoric organisms that existed millions of years ago. Fossil fuels are nonrenewable resources; Earth has a finite supply of fossil fuels that are depleted by use.
Coal is a black combustible solid formed from the remains of ancient plants that lived millions of years ago.
Oil is a thick, yellow to black, flammable liquid hydrocarbon mixture.
Natural gas is a mixture of gaseous hydrocarbons (primarily methane) that often occurs with oil deposits.
2.) Describe the processes that formed coal, oil, and natural gas.
Coal was formed when partially decomposed plant material was exposed to heat and pressure for aeons, forcing out water and concentrating energy in chemical bonds. Oil and natural gas formed when countless microscopic aquatic organisms died and settled in oxygen-deficient sediments.
3.) Relate fossil fuels to the carbon cycle.
The energy in fossil fuels was captured through photosynthesis. Carbon was captured over a long period and has been stored in fossil fuels for millions of years. Over the past century, much of that carbon has been released into the atmosphere through combustion, a trend that is increasing worldwide.
4.) Distinguish between surface mining and subsurface mining.
Surface mining is the extraction of mineral and energy resources near Earth’s surface by first removing the soil, subsoil, and overlying rock strata.
Subsurface mining is the extraction of mineral and energy resources from deep underground deposits. In the United States, surface mining accounts for 60% of the coal mined, and subsurface mining accounts for 40%.
5.) Summarize the environmental problems associated with using coal.
Surface mining destroys existing vegetation and topsoil. As with all fossil fuels, the combustion of coal produces several pollutants—in particular, large amounts of the greenhouse gas carbon dioxide.
Acid mine drainage and acid deposition are two significant types of pollution associated with coal mining and combustion. Burning coal releases CO2 to the atmosphere, contributing to global climate disruption and ocean acidification.
6.) Define resource recovery and fluidized-bed combustion.
Resource recovery is the process of removing any material from polluted emissions or solid waste and selling it as a marketable product.
Fluidized-bed combustion is a technology in which crushed coal is mixed with limestone to neutralize the acidic sulfur compounds produced during combustion.
7.) Define structural trap and give two examples.
Structural traps are underground geologic structures that tend to trap any oil or natural gas present. Structural traps include upward foldings of rock strata and salt domes (underground columns of salt).
8.) Explain what is meant by peak oil and why it might concern us.
Peak oil is the point at which global oil production has reached a maximum rate. Once that peak is passed, less and less oil will be removed each year. By some estimates, we are just about at that peak; by others, peak oil remains decades away.
9.) Discuss the environmental problems of using oil and natural gas.
Oil exploration and extraction are a threat to environmentally sensitive areas. Oil spills can occur during extraction or transportation, creating environmental crises. Removing natural gas from shale using hydraulic fracturing creates large amounts of contaminated wastewater, and creates noise and dust; moving equipment and water also damages infrastructure. CO2 emissions released when oil and natural gas are burned contribute to global climate warming. Production of nitrogen oxides when oil is burned contributes to acid deposition.
10.) Summarize the continuing controversy surrounding oil drilling in the Arctic National Wildlife Refuge.
Supporters of drilling in the Arctic National Wildlife Refuge say that development of domestic oil would improve the balance of trade and make us less dependent on foreign countries for our oil. Conservationists think oil exploration poses permanent threats to the delicate balance of nature in the Alaskan wilderness, in exchange for a temporary (and prob- ably relatively small) oil supply.
11.) Define synfuel and distinguish among tar sands, oil shales, gas hydrates, liquid coal, and coal gas.
Synfuel is a liquid or gaseous fuel that is synthesized from coal and other naturally occurring resources and used in place of oil or natural gas. Tar sands are underground sand deposits permeated with bitumen, a thick, asphalt-like oil. Oil shales are sedimentary rocks containing a mixture of hydrocarbons known collectively as kerogen. Gas hydrates are reserves of ice-encrusted natural gas located deep underground in porous rock. Coal liquid is a liquid fuel similar to oil, produced from coal by the process of coal liquefaction. Another synfuel, coal gas, is a gaseous product of coal.
12.) Briefly consider the environmental implications of using synfuels.
Synfuels have many of the same undesirable effects as fossil fuels. Their combustion releases enormous quantities of CO2 and other pollutants into the atmosphere, thereby contributing to global warming and air pollution. Some synfuels, such as coal gas, require large amounts of water during production and are of limited usefulness in arid areas. Enormously large areas of land would have to be surface mined to recover the fuel in tar sands and oil shales.
1.) Distinguish between active and passive solar heating and describe how each is used.
Passive solar heating is a system of putting the sun’s energy to use without requiring mechanical devices (pumps or fans) to distribute the collected heat. Currently, about 7% of new homes built in the United States have passive solar features.
Active solar heating is a system of putting the sun’s energy to use in which a series of collectors absorb the solar energy, and pumps or fans distribute the collected heat. Active solar heating is used for heating water and, to a lesser extent, space heating.
2.) Contrast the advantages and disadvantages of solar thermal electric generation and photovoltaics for converting solar energy into electricity.
Solar thermal electric generation is a means of producing electricity in which the sun’s energy is concentrated by mirrors or lenses onto a fluid- filled pipe; the heated fluid is used to generate electricity. Solar thermal plants are not yet cost-competitive with traditional fuels, but they are more efficient than other direct solar technologies, and they do not produce air pollution or contribute to acid rain or global climate change.
Photovoltaics (PV) include solar cells, wafers or thin-films of solid-state materials, such as silicon or gallium arsenide, that are treated with certain metals so that they generate electricity—that is, a flow of electrons—when they absorb solar energy. PV devices generate electricity with no pollution and minimal maintenance, but most are only about 10% to 15% efficient at converting solar energy to electricity.
3.) Define biomass, explain why it is an example of indirect solar energy, and outline how it is used as a source of energy.
Biomass consists of plant material that is used as fuel. Biomass is an example of indirect solar energy because it includes organic materials produced by photosynthesis. Biomass is burned directly to produce heat or electricity or converted to solid (charcoal), gas (biogas), or liquid (methanol and ethanol) fuels. Biomass is already being used for energy on a large scale, particularly in developing nations. India and China have several million biogas digesters that produce biogas from household and agricultural wastes.
4.) Describe the locations that can make optimum use of wind energy and of hydropower, and compare the potential of wind energy and hydropower.
Wind energy is electric energy obtained from surface air currents caused by the solar warming of air. Harvesting wind energy to generate electricity has great potential because it is currently the most cost- competitive of all forms of solar energy. Harnessing wind energy is most profitable in areas with fairly continual winds, such as islands, coastal areas, mountain passes, and grasslands.
Hydropower relies on flowing or falling water to generate electricity. The damming of rivers and streams to generate electricity is the major form of hydropower. Currently, hydropower produces about 19% of the world’s electricity. Environmental and social problems associated with hydropower include ecological destruction upstream and downstream, increased evaporation of water, disease and pollution, displacement of people, and inundation of farmland.
5.) Describe geothermal energy and tidal energy, the two forms of renewable energy that are not direct or indirect results of solar energy.
Geothermal energy is the use of energy from Earth’s interior for either space heating or the generation of electricity. Geothermal energy can be obtained from hydrothermal reservoirs of heated water near Earth’s surface. The established technology for extracting geothermal energy from heated areas of Earth’s crust involves drilling wells and bringing the steam or hot water to the surface.
Tidal energy is a form of renewable energy that relies on the ebb and flow of the tides to generate electricity; it is currently used on a very limited scale.
6.) Distinguish between nuclear energy and chemical energy.
In ordinary chemical reactions, the atoms of one element do not change into atoms of another element, nor does any of their mass (matter) change into energy. In contrast, nuclear energy is the energy released by nuclear fission or fusion. In nuclear energy small amounts of matter from atomic nuclei are converted into large amounts of energy.
7.) Describe the nuclear fuel cycle, including the process of enrichment.
The nuclear fuel cycle includes the processes involved in producing the fuel used in nuclear reactors and in disposing of radioactive wastes (or nuclear wastes).
Enrichment, which is part of the nuclear fuel cycle, is the process by which uranium ore is refined after mining to increase the concentration of fissionable U-235.
8.) Define nuclear reactor and describe a typical nuclear power reactor.
A nuclear reactor is a device that initiates and maintains a controlled nuclear fission chain reaction to produce energy for electricity. A typical reactor contains a reactor core, where fission occurs; a steam generator; a turbine; and a condenser. The reactor core contains fuel rods filled with pellets of uranium dioxide. Above each fuel assembly is a control rod that is moved into or out of the fuel assembly, thereby producing the amount of fission required. The fission of U-235 releases heat that converts water to steam, used to generate electricity. Safety features include a containment building built of steel-reinforced concrete. Conventional nuclear fission uses U-235, which makes up about 3% to 5% of uranium after enrichment. Spent fuel is the used fuel elements that were irradiated in a nuclear reactor.
9.) Discuss the pros and cons of electric power produced by nuclear energy.
Nuclear power can serve as an alternative to electricity generation from coal and natural gas, both of which contribute greenhouse gases to the atmosphere. One reason proponents of nuclear energy argue for its widespread adoption is that it has less of an environmental impact than fossil fuels, particularly coal. Nuclear energy emits few pollutants into the atmosphere and provides power without producing carbon dioxide. However, it generates highly radioactive waste such as spent fuel; every country that uses nuclear power is seeking a permanent waste-disposal site. Safety remains a concern at nuclear power plants.
10.) Describe the nuclear power plant accidents at Three Mile Island, Chernobyl, and Fukushima Daiichi.
The most serious nuclear reactor accident in the United States occurred in 1979 at the Three Mile Island power plant in Pennsylvania. A partial meltdown of the reactor core took place, although the containment build- ing kept almost all the radioactivity from escaping. In 1986 a nuclear reactor accident occurred in Chernobyl in the former Soviet Union (now Ukraine). One or two explosions ripped apart a nuclear reactor and expelled large quantities of radioactive material into the atmosphere, resulting in widespread environmental pollution as well as serious local contamination. At the Fukushima Daiichi nuclear power plant in Japan, three reactors melted down following inundation by a tsunami in March 2011. Over 400,000 people were evacuated, and the impacts of the accident and resulting radiation will continue to have impacts for decades to come.
11.) Distinguish between low-level and high-level radioactive wastes.
Low-level radioactive wastes are radioactive solids, liquids, or gases that give off small amounts of ionizing radiation.
High-level radioactive wastes are solids, liquids, or gases that initially give off large amounts of ionizing radiation.
12.) Explain the pros and cons of on-site storage and deep geologic disposal.
On-site storage in liquid is necessary for a short period of time, as spent fuel rods cool. However, spent fuel rods cannot be safely stored in liquid for long periods. The National Research Council suggests that deep geologic storage is the safest and most secure long-term solution for high- level nuclear wastes. Until a storage facility is licensed and constructed, on-site dry cask storage in large, expensive steel and concrete cylinders will be increasingly common.
13.) Briefly describe how future nuclear power reactors might differ from current plants.
The next generation of nuclear power plants is expected to be smaller, simpler, safer, and more cost-effective than the reactors currently in use around the world. The NRC has already approved four new designs, and more are proposed. Nuclear fusion as a source of energy is many years from becoming a reality.