Environmental Science Final Exam Review

Energy

The ability to do work or transfer heat.

Fossil Fuel

A nonrenewable energy source formed from ancient plants and organisms over millions of years under heat and pressure.

Coal

A fossil fuel formed primarily from ancient terrestrial plants that accumulated in oxygen-poor swamps about 300 million years ago.

Peat

Partially decayed plant material that represents the earliest stage of coal formation.

Lignite

The lowest-grade coal with the lowest carbon content, lowest energy value, and highest moisture content.

Bituminous Coal

The most abundant and widely used type of coal for electricity generation and industry.

Anthracite

The highest-grade coal with the highest carbon content, highest energy value, and cleanest burn.

Coal Seam

A layer of coal found underground between layers of rock.

Overburden

The layers of soil and rock above a coal seam that must be removed before surface mining.

Surface Mining

Mining that removes soil and rock to access mineral deposits near Earth's surface.

Strip Mining

A type of surface mining that removes long strips of overburden to expose shallow coal seams.

Mountaintop Removal

A mining technique in which the tops of mountains are blasted away to expose coal, causing extensive environmental damage.

Underground Mining

Mining that extracts coal through tunnels beneath Earth's surface.

Acid Mine Drainage

Acidic water produced when sulfur-containing minerals react with oxygen and water, releasing sulfuric acid and dissolved metals into streams.

Sulfur

An element commonly found in coal that can produce sulfur dioxide when burned.

Sulfur Dioxide (SO₂)

An air pollutant released from burning sulfur-containing fossil fuels that contributes to acid rain.

Particulate Matter

Tiny solid or liquid particles suspended in the air that can damage human health and reduce air quality.

Carbon Dioxide (CO₂)

The primary greenhouse gas released during fossil fuel combustion.

Greenhouse Gas

A gas that absorbs and re-emits infrared radiation, trapping heat in Earth's atmosphere.

Combustion

The burning of a fuel in the presence of oxygen to release energy.

Petroleum

A liquid fossil fuel formed primarily from ancient marine organisms and refined into gasoline, diesel, jet fuel, and many other products.

Crude Oil

Unrefined petroleum extracted from underground reservoirs before processing.

Natural Gas

A fossil fuel composed primarily of methane that burns cleaner than coal and petroleum.

Methane (CH₄)

The main component of natural gas and a greenhouse gas much more potent than carbon dioxide over short time periods.

Hydraulic Fracturing (Fracking)

A method of extracting natural gas and oil by injecting high-pressure water, sand, and chemicals into rock formations.

Horizontal Drilling

A drilling technique that extends horizontally through rock layers to increase access to oil and natural gas.

Shale Gas

Natural gas trapped within shale rock formations and commonly extracted through fracking.

Oil Sands (Tar Sands)

Deposits of sand, clay, water, and bitumen that can be processed to produce petroleum.

Bitumen

A thick, heavy form of petroleum extracted from oil sands.

Peak Oil

The point at which oil production reaches its maximum rate before beginning a long-term decline.

Hubbert Curve

A bell-shaped curve used to predict the production and depletion of finite fossil fuel resources.

Carbon Capture and Storage (CCS)

Technology that captures carbon dioxide emissions from power plants or industrial facilities and stores them underground to reduce greenhouse gas emissions.

Carbon Sequestration

The long-term storage of carbon in forests, soils, oceans, or underground geological formations.

Energy Density

The amount of energy stored per unit mass or volume of a fuel.

Nonrenewable Resource

A natural resource that forms much more slowly than it is consumed.

Renewable Resource

A natural resource that is naturally replenished on a human timescale.

Air Pollution

The contamination of the atmosphere by harmful gases or particles that can affect human health and ecosystems.

Acid Rain

Precipitation made acidic by sulfur dioxide and nitrogen oxides reacting with water in the atmosphere.

Nitrogen Oxides (NOₓ)

Air pollutants produced during fossil fuel combustion that contribute to acid rain and smog.

Smog

Air pollution formed by chemical reactions involving sunlight, nitrogen oxides, and volatile organic compounds.

Volatile Organic Compounds (VOCs)

Organic chemicals that easily evaporate into the air and contribute to smog formation.

Mine Reclamation

The process of restoring land after mining operations have ended.

Reclamation

Returning disturbed land to a stable, productive, or natural condition after resource extraction.

Fossil Fuel Subsidy

Government financial support that lowers the cost of producing or consuming fossil fuels.

Energy Transition

The shift from fossil fuels toward cleaner and more sustainable energy sources.

Renewable Energy

Energy obtained from naturally replenished resources that can be used repeatedly without being depleted.

Alternative Energy

Energy sources used instead of fossil fuels, including both renewable sources and nuclear energy.

Nonrenewable Energy

Energy obtained from finite resources that cannot be replenished on a human timescale.

Solar Energy

Energy produced from the sun's radiation.

Solar Photovoltaic (PV)

Technology that converts sunlight directly into electricity using semiconductor materials.

Photovoltaic Cell

A device that converts solar energy directly into electrical energy.

Solar Panel

A collection of photovoltaic cells used to generate electricity from sunlight.

Solar Thermal Energy

A system that captures the sun's heat to produce hot water or electricity.

Concentrated Solar Power (CSP)

A solar technology that uses mirrors to concentrate sunlight and produce steam for electricity generation.

Passive Solar Heating

The use of building design to collect and store solar heat without mechanical equipment.

Active Solar Heating

A system that uses pumps or fans to circulate heat collected from solar energy.

Wind Energy

Electricity generated by converting the kinetic energy of moving air into electrical energy.

Wind Turbine

A machine that converts the kinetic energy of wind into electricity.

Wind Farm

A collection of wind turbines used to generate electricity on a large scale.

Offshore Wind Farm

A wind farm located in oceans or large lakes where wind speeds are generally higher and more consistent.

Capacity Factor

The percentage of a power plant's actual electricity production compared to its maximum possible output.

Intermittency

The inconsistent availability of renewable energy due to changing weather or daylight conditions.

Hydroelectric Power

Electricity generated by moving water turning turbines.

Hydroelectric Dam

A structure built across a river to store water and generate electricity.

Reservoir

A large body of stored water behind a dam.

Run-of-the-River Hydropower

Hydroelectric generation that relies on the natural flow of a river with little water storage.

Biomass

Organic material from plants or animals used as an energy source.

Biofuel

Fuel produced from biomass rather than fossil fuels.

Ethanol

An alcohol fuel commonly produced from corn or sugarcane and blended with gasoline.

Biodiesel

A renewable fuel produced from vegetable oils, animal fats, or recycled cooking grease.

Cellulosic Ethanol

Ethanol produced from non-food plant materials such as grasses or crop residues.

Geothermal Energy

Energy obtained from heat naturally stored beneath Earth's surface.

Geothermal Power Plant

A facility that converts underground heat into electricity.

Ground Source Heat Pump

A heating and cooling system that transfers heat between a building and the ground.

Heat Pump

A device that moves heat from one location to another for heating or cooling.

Nuclear Energy

Energy released from changes within an atom's nucleus.

Nuclear Fission

The splitting of a large atomic nucleus into smaller nuclei, releasing large amounts of energy.

Nuclear Fusion

The combining of small atomic nuclei into a larger nucleus, releasing enormous amounts of energy.

Uranium

A radioactive element commonly used as fuel in nuclear reactors.

Uranium-235

The fissile isotope of uranium used in most nuclear power plants.

Fuel Rod

A sealed tube containing uranium fuel used inside a nuclear reactor.

Control Rod

A rod made of materials that absorb neutrons to regulate the rate of nuclear fission.

Moderator

A substance that slows neutrons to sustain a controlled nuclear chain reaction.

Chain Reaction

A self-sustaining series of nuclear fission reactions.

Nuclear Reactor

A facility where controlled nuclear fission produces heat for electricity generation.

Steam Turbine

A turbine rotated by high-pressure steam to generate electricity.

Cooling Tower

A structure that removes excess heat from a power plant by cooling water.

Radioactive Waste

Materials remaining after nuclear reactions that continue to emit radiation.

High-Level Radioactive Waste

Highly radioactive waste produced from spent nuclear fuel.

Low-Level Radioactive Waste

Radioactive waste containing relatively low concentrations of radioactive materials.

Half-Life

The time required for half of the atoms in a radioactive substance to decay.

Radiation

Energy emitted as particles or electromagnetic waves from radioactive materials.

Baseload Power

Electricity supplied continuously to meet minimum demand.

Energy Storage

The capture of energy for later use when electricity demand increases.

Battery Storage

The storage of electrical energy in rechargeable batteries for later use.

Pumped Hydroelectric Storage

A method of storing energy by pumping water uphill during low demand and releasing it to generate electricity during high demand.

Transmission Grid

The network of power lines that transports electricity from producers to consumers.

Smart Grid

An electricity network that uses digital technology to improve efficiency, reliability, and communication.

Distributed Generation

Electricity produced close to where it is used rather than at a centralized power plant.

Net Metering

A billing system that credits customers for excess electricity they generate and send to the grid.