Environmental Science Test 3

Science

A process used to solve problems or develop an understanding of nature that involves testing possible answers.

• modern science is based on demonstrable and reproducible data and aims for results through testing and analysis

• likened to a ‘mall cop’

scientific method

an empirical way of gaining information (facts) about the world by forming possible solutions to questions, followed by rigorous testing to determine of the proposed solutions are valid.

basic assumptions in science

1. specific causes exist for observed events

2. these causes can be identified

3. general rules or patterns can be used to describe observations

4. repeated events probably have the same cause

5. perceptions are not individualistic

6. fundamental rules of nature are universal

Science does not…

• make moral or aesthetic judgments

• tell you how to use scientific knowledge

• draw conclusions about supernatural explanations

scientific method

• observe

• hypothesis

• experiment/test

• analyze results

• conclusions

• comunicate

underlying all of these activities is constant attention to accuracy and freedom from bias

hypothesis

a testable statement (suggestion) that provides a possible answer to a question, or an explanation for an observation

• normally in the form of an “if/then” statement

• must be testable and falsifiable

testable

possible to make observations that agree or disagree with it

falsifiable

must be a possible negative answer; if a hypothesis is false, it must be able to be shown false

experiment

a re-creation of an event that enables an investigator to support or disprove a hypothesis

controlled experiment

divides experiment into two groups (experimental and control) that differ by only one variable

reproducibility

important to the scientific method

• a good experiment must be able to be repeated by independent investigators to ensure a lack of bias

matter

anything that has mass and takes up space

atom

fundamental unit of matter

• 92 atoms found in nature

• composed of protons, neutrons, and electrons

• each kind of atom forms a specific type of matter —> element

• all atoms of the same element have the same number of protons and electrons, but may vary in number of neutrons

protons

positively charged

neutrons

neutral charge

electrons

negatively charged

isotopes

atoms of the same element that differ from one another in the number of neutrons they contain

particles

can be atoms, molecules, or ions

• atoms: single neutral particle

• molecules: atoms bonded together into neutral units

• ions: positively or negatively charged particles; number of protons do not equal number of electrons

atoms that lose electrons are __________ charged

positively

atoms that gain electrons are _________ charged

negatively

compounds

formed when two or more atoms or ions bind to one another

Water

• water can exist in 3 phases: solid, liquid, gas

• ¾ of the earth’s surface is covered with water

• water determines the weather and climate of a region, and the flow of water and ice shape the earth’s surface

• the most common molecule found in living things is water

• water molecules are polar with positive and negative end

• water is the universal solvent

solids

molecular particles have low energy and vibrate in place very close to one another

liquids

more energy; molecules are farther apart from one another

gases

molecular particles move very rapidly and are very far apart

sensible heat transfer

occurs when heat energy flows, or is transferred, from a warmer object to a cooler object without a phase change.

latent heat transfer

occurs when heat energy is used to change the state of matter, but the temp of matter does not change

• i.e. liquid to gas at its boiling point

acid

any compound that releases hydrogen (H+) ions in a solution

base

any compound that accepts hydrogen ions in a solution

pH (power of hydrogen)

number that expresses the concentration of an acid or base solution

• pH scale measures H ion in concentration

• scale is inverse and logarithmic

pH scale

7 = neutral

0-6 = acidic (fewer OH than H+) or (H+>OH-)

8-14 = basic (more OH than H+) or (H+<OH-)

organic matter

consists of molecules that contain carbon atoms that are usually bonded to form rings or chains

• all living things contain molecules of organic compounds

chemical bonds

attractive forces between atoms resulting from the interaction of their electrons.

• when chemical bonds are formed or broken, a chemical reaction occurs

• typically, chemical bonds in organics molecules contain a large amount of chemical energy that can be released when the bonds are broken

Exothermic reactions

more energy is released when the bonds in the reactants are broken than is used when new bonds are formed in the products → releases energy in form of heat , higher temp of rxn

endothermic reactions

more energy is used when the bonds are formed in the products than is used to break the bonds in the reactants

• absorbs/requires energy in form of heat, lower temp of rxn

exergonic reaction

energy released (exits)

endergonic reaction

energy required (input/enter)

activation energy (E_a)

initial input of energy required to start a reaction

catalyst

a substance that alters the rate of reaction, without being consumed or altered itself in the process

• can reduce activation energy

enzymes

contained in living organisms

• reduce the activation energy needed to start reaction

photosynthesis

process used by plants to convert inorganic material into organic material using light

respiration

process that uses O₂ to break down large, organic molecules into smaller inorganics molecules (releases energy organisms can use)

energy

ability to perform work

work

conducted when an object is moved over a distance

potential energy

energy due to relative position (stored)

• water behind a dam

kinetic energy

energy contained by moving objects; energy of motion

• water running downhill, dog chasing a ball

1st law of thermodynamics

energy cannot be created nor destroyed; it can only be changed from one form to another 

2nd law of thermodynamics

when converting energy from one to another, some of the useful energy is lost as heat

entropy

energy that cannot be used to do useful work

• dispersal of energy or energy spread

photosynthesis

first transfer of energy

• sun → plants → herbivores → carnivores

nonrenewable

exhaustible resources

• coal, gas, oil, uranium etc

renewable

essentially inexhaustible on the human time scale

• solar, wind, geothermal, tidal, hydropower, etc

Carboniferous Period

Conditions were conducive to the formation of large deposits of coal

• 299-359 million years ago

fossil fuels

modified remains of plants, animals, and microorganisms that lived millions of years ago

coal

major fossil fuel formed during the carboniferous period 

steam engines

converted heat energy into forward motion, central to transformation in time of industrial revolution

• countries without large coal deposits were largely consequently behind

cottage industry

pre-industrial revolution, goods manufactured on small scale in private homes

what invention dramatically increased demand for oil products?

the automobile

Federal-Aid Highway Act of 1956

41,000 miles of highway built

How did cars alter people’s lifestyles?

• vacationers could travel greater distances

• people could live farther from work, leading to sprawling cities and suburbs

• in suburbs, labor-saving, energy-consuming devices became essential in the home

• we expect to see products from all over the country/world in grocery stores

electricity

the flow of electrical power or charge

• most electrical energy is produced as a result of burning fossil fuels

• easily transported, and uses are so varied

5 key factors that influence price of electricity

1. fuels

2. power plants

3. transmission and distribution system

4. weather conditions

5. regulations

how many gallons of gasoline and diesel fuel are made from one barrel of oil?

• (one barrel holds 42 gallons)

• 19 to 20 gallons of motor gasoline

• 11 t0 12 gallons of ultra-low sulfur distillate fuel oil

4 main components of retail price of gasoline

1. cost of crude oil

2. refining costs and profits

3. distribution and marketing costs and profits

4. taxes

U.S. federal excise tax on gasoline

• 18.4 cents per gallon

• 24.4 cents per gallon for diesel fuel

Organization of Petroleum Exporting Countries (OPEC)

• Consists of 15 countries

• Control about 80% of the world’s estimated oil reserves

Organization for Economic Cooperation and Development (OECD)

Over half of world energy consumption is by these 25 member countries, the developed nations of the world

economic growth

(as measured by GDP) a key determinant in the growth of energy demand

Hydraulic fracturing- “fracking”

categories of coal

• Lignite

• Sub-bituminous

• Bituminous: most abundant coal found in U.S.

• Anthracite: highest value of carbon

thermal coal (steam coal)

variety of coal used for power generation

metallurgical coal (steelmaking coal)

• primary ingredient in the steel making process

• typically contains more carbon, less ash and more moisture than thermal coal

2 extraction methods for coal

surface mining (strip mining/ ‘opencast’)

• process of removing materials on top of a vein

• efficient but destructive

• often used when coal is less than 200 feet underground

Underground mining (‘deep’)

• minimizes surface disturbance, but costly and dangerous

• many miners suffer from black lung disease

issues related to the use of coal

• coal is bulky and causes some transport problems

• mining creates dust pollution

• burning coal releases pollutants (carbon and sulfur)

• landscape disturbances

• acid mine drainage

• air pollution

reclamation

reclaiming the land and restoring it?

oil and natural gas origin

microscopic marine organisms that accumulated on the ocean floor and were covered by sediments

• muddy rock gradually formed shale containing dispersed oil

• natural gas often forms on top of oil

issues related to the use of oil

oil is more concentrated than coal, burns cleaner, and is easily transported through pipelines

• these qualities make it ideal for automobile use

• it is difficult to find

• it causes less environmental damage than coal mining

recovery methods of oil and gas

• Primary Recovery methods: extracting oil via either the natural rise of hydrocarbons to the surface of the earth or via pump jacks and other artificial lift devices

• Secondary Recovery methods: water injected into a well to drive the oil out of the pores in the rock

• technique allow up to an additional 30% of the oil to be extracted

• Tertiary Recovery methods (Enhanced Oil Recovery- EOR): Three main types: thermal recovery, gas injection, chemical injection (chemical- CO₂, thermal- steam)

refining crude oil

• processing: as it comes from the ground, oil is not in a form suitable for use and must be refined. multiple products can be produced from a single barrel of crude oil

• “cracking”: heat, pressure, and catalysts are used to produce a higher percentage of volatile chemicals (gasoline) from less volatile liquids (diesel fuel and furnace oils)

• a 42-gallon barrel of crude oil yields about 45 gallons of petroleum products in U.S.

Oil spills

• accidental spills only account for about 1/3 of oil pollution resulting from shipping

• 60% comes from routine shipping operations

• accidental releases are a small component of oil released into oceans of the world

Arctic National Wildlife Refuge (ANWR)

• 1960- originally 8.9 mil acres set aside as arctic national wildlife range

• 1980- added 9.1 mil acres

• currently: 19,64 mil acres of land and water

• major issue is porcupine caribou and their migration

• international implications: borders Canada’s northern yukon national park

• coastal plain (or 1002 Area) cover 1.5 mil acres and is about 8% of the total area of ANWR

associated vs. non-associated natural gas

associated: natural gas produced by oil wells

non-associated: natural gas produced by natural gas wells

some states define an oil well versus a natural gas well differently base don different gas-oil ratios (GOR). 

• <=6,000 cf/b = oil well 

• > 6,000 cf/b = gas well

Natural Gas Use

• Liquefaction at -126^o F (1/600 volume of gas)

• natural gas is least disruptive to environment (no unsightly waste, may be local odor problem, no harm during transport, clean burning = almost no air pollution, combustion products = water/CO₂ )

what percentage of total energy use does nuclear energy make up?

9%

U.S. nuclear power information

• USA is world’s largest producer of nuclear power, accounting for more than 30% of worldwide nuclear generation of electricity

• about 19% of total electrical output

• currently, almost all the uranium used in US commercial reactors is imported. (domestic mining now accounts for about 5% of fuel used in US reactors)

• 94 operable reactors 

• USA ranks 15^th in the world for known uranium resource, about 1% of world total

Executive Orders on nuclear power

• reestablish US as global leader in nuclear energy

• facilitate increased deployment of new nuclear reactor technologies

• facilitate the expansion of American nuclear energy capacity from approximately 100GW in 2024 to 400GW by 2050

• employ emerging technologies to safely accelerate the modeling, simulation, testing, and approval of new reactor designs

• support the continued operation of, and facilitate appropriate operational extensions for, the current nuclear fleet, as well as the reactivation of prematurely shuttered or partially completed nuclear facilities

• maintain the United States’ leading reputation for nuclear safety

2 types of reactors

Pressurized Water Reactor (PWR)

• 2/3 of reactors in US

Boiling Water Reactor (BWR)

• 1/3 of reactors in US

what percentage of the worlds energy supply does alternate energy supply?

• 29%

• renewable sources include: biomass conversion, hydroelectric power, solar energy, wind energy

biomass

• all biomass is produced by green plants that convert sunlight into plant material through photosynthesis

• biomass is still the predominant form of energy used by people in less-developed countries (accounts for about 6% of world energy use)

• in developing countries 2.5 billion people rely on biomass such as fuelwood, charcoal, agricultural waste, and animal dung, to meet their energy needs for cooking

fuelwood

~3 billion people rely on it

kuznets curve

the more economically prosperous a country is, the more they can care about the environment

how much biomass is used for fuel in the united states?

• biomass fuels provided about 5% of total primary energy use in the U.S in 2022

• of that 5%, 48% is biofuels (mainly as ethanol)

Municipal (MSW) and Industrial wastes

• 80% combustible, over 60% derived from biomass

• lots of food waste

agricultural crop residues and animal wastes

• animal waste dried and burned

• crop residue removed from fields (disadvantage of increased erosion, less organic matter decay)

energy plantations

dedicated area of land that is cultivated specifically for the purpose of producing biomass for energy production

• fast-growing trees, shrubs, or grasses that can be harvested and converted into biofuels, such as ethanol or biodiesel, or burned to generate electricity

• feedstocks: switchgrass, sunflowers, canola, sugar cane

• fast-growing trees: willow, poplar, and eucalyptus

WTE (waste to energy) plants

account for 0.4% of total electricity generation

why biofuels can’t replace oil

• biofuels have lower energy densities, so more fuel is needed to supply the same amount of energy

• thus, biofuels contradict state and national goals of increased energy efficiency to reduce GHG emissions and lower energy consumption

• 1 gallon of ethanol contains the same energy as 0.66 gallons of gasoline

hydroelectric power

• currently supplies 16% of world’s electricity

• first U.S. hydroelectric power plant: September 30, 1882

• most plants are in pacific northwest?

hydroelectric power: environmental issues

1. flooding of vast areas of land (three gorges dam in China)

2. alters watershed

3. changes flow of river and quality of water in downstream river

4. alter fish migration patterns

solar energy

daily energy from the sun is 600x greater energy produced each day by all other energy sources combined

• major problems with solar energy are its intermittent and diffuse nature