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Abiotic - Non-living components of an ecosystem. Ampere - (abbrev. Amp; pl. Amperes [Amps]) A unit of electric current. One ampere of current is equal to one coulomb (6.25 x 1,018) of electrons passing a point in an electric circuit in one second. See Electric current. Atom - 1. The smallest unit of an element, consisting of a dense, central core (the nucleus) made of protons and neutrons that is surrounded by orbiting electrons. 2. The smallest unit of matter that can enter into a chemical reaction. Autotroph - An organism capable of synthesizing its own food from inorganic substances using light or chemical energy. Examples of autotrophs include plants and some protozoans. Battery - A device that converts chemical energy into electrical energy, producing an electric current when connected in a circuit. Biodiversity - The variety of individual organisms (genetic), species, and ecosystems. Biogeochemical cycle - A natural process that cycles nutrients in various chemical forms from the environment, to organisms, and then back to the environment. Examples are the carbon, oxygen, nitrogen, phosphorus, and hydrologic cycles. Biological community - All the organisms (e.g., plants, animals, bacteria) that live in an area and interact with each other. See Ecosystem. Biomass - Plant or animal matter. Biomass can be burned directly as a source of heat or converted to a more convenient gaseous or liquid fuel. Examples include wood and animal waste. Biosphere - The parts of Earth where life is found, including the land, bodies of water, and the lower part of the atmosphere. Biotic - Living components of an ecosystem. British thermal unit - (abbrev. Btu) 1. A unit of energy equal to 1,055 joules or 252 calories. 2. The amount of energy needed to raise the temperature of one pound of water one degree Fahrenheit. 3. The approximate amount of potential energy in one match tip. Calorie - (abbrev. cal; pl. calories; also small calorie) 1. A unit of energy content of food. One calorie equals 4.187 joules or 0.003969 Btu. 2. The amount of energy needed to raise the temperature of one gram of water one degree Celsius. Calorimeter - A device used to measure the heat energy that flows into or out of a substance. Carbohydrate - An organic compound produced by photosynthesis, such as sugar, starch, and cellulose and used as a source of food energy by organisms. Carbon cycle - A biogeochemical cycle in which carbon and its compounds are exchanged between organisms and Earth's oceans, atmosphere, and crust. See Biogeochemical cycle. Carnivore - An organism that obtains its food energy by eating animals. See Secondary consumer. CCF - One hundred cubic feet of water or natural gas. One CCF of natural gas is about equal to one therm. Cell - The smallest living unit of an organism. A cell consists of genetic material contained in one or more nuclei plus other organelles to perform various life functions, all of which are encased in an outer membrane. Celsius - (also Celsius scale, centigrade. Celsius is the term preferred over centigrade.) A temperature scale on which the freezing point of water is 0 degrees Celsius and the boiling point of water is 100 degrees Celsius (at one atmosphere of pressure). The formula for converting temperatures from the Celsius scale to the Fahrenheit scale is oC=5/9 (oF -32). See Fahrenheit. Chain reaction - (also Nuclear chain reaction) 1. A reaction that stimulates its own repetition. 2. For example, nuclear reaction occurs when neutrons released from a split atom such as a uranium-235 (U235) nucleus go on to fission other nuclei. This reaction produces additional neutrons that cause more fissions, which release still more neutrons to cause even more fissions, which release even more neutrons, and so on. See Fission. Chemical bond - An attractive force that holds atoms together to form molecules. Chemical energy - See Chemical potential energy. Chemical potential energy - The energy in chemical bonds holding the atoms of a compound together. Food, wood, batteries, and fossil fuels contain chemical potential energy. See Chemical bond. Coal - A fossil fuel made of sedimentary organic rock that contains more than 40 percent carbon by weight after moisture has been removed. It is formed from plant matter that decayed in swamps and bogs that has been compressed and altered by geological processes over millions of years. Four main types of coal have been identified and ranked based on how much carbon and energy they contain: lignite, subbituminous coal, bituminous coal, and anthracite. Compact fluorescent lamp (abbrev. CFL) - A small fluorescent lamp designed to fit in light fixtures that use standard incandescent lamps. Compact fluorescent light bulb - See Compact fluorescent lamp. Conduction - 1. Heat transfer from particle to particle, occurring most effectively in solids. 2. Transfer of electrical energy through a material via the flow of charged particles, usually electrons. Conservation - Wise use and careful management of resources, so as to obtain the maximum possible social benefits from them for present and future generations. Energy resources can be conserved by reducing wasteful energy use, using energy for a given purpose more efficiently, or by reducing energy use altogether. Consumer - 1. An organism that obtains nutrients and energy by eating other organisms. 2. A person or group of persons who buys and uses goods and services. See Primary consumer, Secondary consumer. Convection - Heat transfer by the movement of liquid and gases. Decomposer - An organism, such as a bacterium or fungus, that feeds on and breaks down parts of dead organisms and the waste products of living organisms. Degree - A unit of measure used to describe a temperature scale. See Celsius, Fahrenheit. Ecosystem - Self-regulating natural community or organisms (e.g., plants, animals, bacteria) interacting with one another and with their nonliving environment. Wetlands, forests, and lakes are examples of ecosystems. Elastic potential energy - The energy in a solid object when it is stretched or compressed. A stretched rubber band has elastic potential energy. Electrical circuit - A closed, conducting path or route through which an electric current travels. Electrical (electromagnetic) energy - Kinetic and potential energy associated with electric charges (e.g., electrons) and their movement. See Electrical potential energy. Electrical potential energy - Energy stored by separating positive and negative electrical charges against electrical forces. A charged battery has electrical potential energy. See Electrical (Electromagnetic) energy. Electric current - A flow of electrically charged particles such as electrons with a conductor or a circuit. See Conduction, Electricity. Electricity - 1. The behavior of negative and positive charges (electrons and protons) due to their attraction and repulsion. 2. The flow of electrons; electric current. See Electrical (Electromagnetic) energy, Electric current. Electron - 1. A subatomic particle with a negative electric charge that orbits the nucleus of an atom. 2. The basic particle that makes up an electric current. End use - A set of devices, products, and systems that use energy for the same or for similar purposes. Examples of residential end uses include cooking, lighting, and refrigeration. Energy - 1. The ability to organize or change matter. 2. The ablility to do work. See British thermal unit, Calorie, Joule, and Kilowatt-hour for units of energy. One unit can be converted to another. Energy charge - The cost of electricity or natural gas energy used by a utility customer. The energy charge equals the amount of electricity or natural gas used by the customer times the electric or natural gas rate. Energy conversion - The process of changing one form of energy into another. For example, the potential chemical energy in gasoline can be converted into kinetic energy (energy of motion) by an automobile energy. See Energy conversion device. Energy conversion device - A device specifically designed to convert one form of energy into another. For example, a solar cell is a device that converts solar energy into electrical energy. See Energy conversion. Energy forms - Basic kinds of energy that are different and distinct from each other. Two main forms of energy are potential energy (the energy stored in matter) and kinetic energy (the energy of motion). More specific forms of energy include thermal, elastic, electromagnetic (e.g., light, electrical, magnetic), gravitational, chemical, and nuclear energy. Energy resource - Energy source that is used to meet the needs of a human society. For example, oil is an energy resource because it is used to produce fuel for transportation and heating needs. Energy resources are subsets of energy sources. See Energy source. Energy source - Matter or a system from which on or more forms of energy can be obtained. For instance, natural gas is a source of thermal energy, and sugarcane is a source of chemical energy. Entropy - 1. A measure of the dispersal or degradation of energy. 2. A measure of the disorder or randomness in a closed system. For example, the entropy of an unburned piece of wood and its surroundings is lower than the entropy of the ashes, burnt remains, and warmed surroundings due to burning the that piece of wood. Fahrenheit - A temperature scale on which the freezing point of water is 32 degrees F and the boiling point of water is 212 degree F (at one atmosphere of pressure). The formula for converting temperatures from the Fahrenheit scale to the Celsius scale is oF - 9/5 (oC + 32). See Celsius. First law of thermodynamics - Energy cannot be created or destroyed; it can only be converted from one form to another. For example, the potential chemical energy in coal can be converted in thermal energy. Fission (also Nuclear fission) - A nuclear process in which the nuclei of a heavy atom (e.g., uranium is split by a neutron, releasing a large amount of energy and additional neutrons. Food calorie - (abbrev. Cal, kcal; also Calorie [written with a capital C], Kilocalorie, Large calorie) A unit of energy equal to one kilocalorie. The food calorie is often used when measuring the energy content of food. Food chain - The transfer of stored (potential chemical) energy through a series of organisms, each eating or decomposing the previous one. Fossil fuels - Carbon-rich fuel formed from the remains of ancient animals and plants. Coal, oil, and natural gas are all fossil fuels. Friction - A force that resists motion between two objects in contact. Friction results in the conversion of mechanical energy into waste heat that dissipates into the surrounding environment. Fusion (also Nuclear fusion) - A nuclear process in which the nuclei of two light, non-radioactive elements (such as isotopes of hydrogen) are forced together at ultra-high temperatures and pressures to form the nucleus of a slightly heavier element (such as helium) with the release of substantial amount of energy. The sun's energy comes from nuclear fusion. Gasoline - A liquid fuel composed of a mixture of small, light hydrocarbons and produced by refining crude oil. Gasoline is mainly used by automobiles, trucks, and other motor vehicles. Generator - A device or machine that converts mechanical energy into electrical energy. Geothermal energy - Energy from the heat inside the Earth, usually carried to the surface by superheated water and steam. Gravitational potential energy - A form of potential energy in objects by separating them from other objects against the force of gravity. A rock sitting on top of a cliff has gravitational potential energy with respect to the ground (the Earth). See Potential energy. Grazing food chain - A food chain sequence beginning with producers converting solar energy to chemical energy in organic compounds, followed by primary consumers eating producers, and secondary consumers eating primary consumers. Heat - The transfer of energy from one object at a higher temperature to another object at a lower temperature. Heat can be transferred by conduction, convection, or radiation. Although technically incorrect, the word heat is often used to mean "thermal energy." See Thermal energy. Heat (thermal) energy - See Thermal energy. Herbivore - An organism that obtains its food energy by eating plants. See Primary consumer. Heterotroph - An organism that cannot synthesize its own food and is dependent on complex organic substances for nutrition. Examples of heterotrophs include mammals. Horsepower (abbrev. hp) - A unit of power. One horsepower equals 550 foot-pounds per second of 746 watts. See Power. Human energy - Energy produced by a human to do work or complete a specific task. Hydroelectric power - Electricity produced by the conversion of kinetic energy from falling water using a generator. See Hydropower. Hydropower - Electricity or mechanical energy produced by the conversion of energy from falling water. Sometimes used to refer only to the production of electricity from falling water. See Hydroelectric power. Incandescent lamp - A lamp that contains a wire filament that produces light when heated by an electric current. See Compact fluorescent lamp. Incandescent light bulb - See Incandescent lamp. Isotope - Different forms of atoms of the same element that have different numbers of neutrons in their nuclei. An element may have a number of isotopes. For example, the three isotopes of hydrogen are protium, deuterium, and tritium. All three have one proton in their nuclei, but deuterium also has one neutron, and tritium has two neutrons. Joule - A unit of energy. One joule equals 0.2388 calories or 0.0009481 Btu. Kilocalorie - (abbrev. Cal, kcal; also Calorie [written with a capital C], Food Calorie, Large calorie) 1. A unit of energy equal to 1,000 calories, 4,187 joules, or 3.969 Btu. 2.The amount of energy needed to raise the temperature of one kilogram of water one degree Celsius. See Calorie, Food calorie. Kilowatt - (abbrev. kW; pl. Kilowatts) - A unit of power equal to 1,000 watts. See Watt. Kilowatt-hour (abbrev. kWh; pl. Kilowatt-hours) - 1. A unit of energy equal to 3,413 Btu or 3,600,000 joules. 2. An amount of energy that results from the steady production or consumption of one kilowatt of power for a period of one hour. Kinetic energy - The energy possessed by a moving object. The formula for kinetic energy is 1/2 (mass) x (velocity)2. Leaking electricity - The energy used by an appliance when the appliance is in its lowest power mode (typically when the appliance is off). A variety of appliances, especially those with remote control devices, consume electricity even after they are turned off. Other appliances, including those with built-in clocks, never stop using electricity. Light - A form of electromagnetic radiation composed of different wavelengths ranging from violet to red that are visible to the naked eye. Light is also a means by which energy can be transferred. Light Energy - See Light. Lumen - A measurement of light output from a lamp, tube, or bulb. Mechanical energy - A combination of potential and kinetic energy. A spring that is expanding and contracting back and forth has mechanical energy. See Kinetic energy, Potential energy. Megawatt - A unit of power equal to one million watts or 1,000 kilowatts. See Watt. Meter - A device used to measure and record the amount of electricity or natural gas a utility customer uses. Meter reader - Utility personnel who read and record information from a customer's electric and natural gas meters so that energy use and energy costs can be calculated. Microclimate - Special conditions of light, moisture, and temperature that occur in a narrowly restricted area within an ecosystem, for example, under a bush or in a small woodland opening. Motor - A device or machine that converts other forms of energy into mechanical energy. Natural gas - An odorless, colorless, gaseous hydrocarbon mixture made up of methane (CH4) and a small percentage of other light hydrocarbons. Natural gas is found naturally underground or produced by gasification of coal. Natural gas is the cleanest burning fossil fuel. Nonrenewable energy resource - Energy resource that is either replenished very slowly or is not replenished at all by natural processes. A nonrenewable resource can ultimately be totally depleted or depleted to the point where it is too expensive to extract and process for human use. Fossil fuels are examples of nonrenewable energy resources. Nuclear energy - A form of potential energy in the nuclei of atoms and released by fission (the splitting of nuclei of heavy atoms such as uranium) or by fusion (the combining of nuclei of light atoms such as hydrogen). See Fission, Fusion. Nuclear fission (or Fission) - Nuclear fission occurs when a neutron splits the nucleus of a large atom, such as U235, into two smaller nuclei, releasing energy and additional neutrons. The extra neutrons then split other nuclei, producing still more neutrons that split more nuclei, and so on. This process is called a nuclear chain reaction. Nuclear waste - (also Radioactive waste) Any waste that results from using radioactive materials for purposes that include electricity production by nuclear power plants, defense activities and nuclear weapons manufacture, medical treatment, nuclear research, industrial processes, and mining and milling of uranium ore. Omnivore - An organism that obtains its food energy by eating both plants and animals. Humans are examples of omnivores. Passive solar heating - A solar heating system that uses a simple solar collector, building materials, or an architectural design to capture and store the sun's heat, but that does not include any mechanical system to transfer the heat to various parts of a home or building. Petroleum - A mixture of liquid, gaseous, and solid hydrocarbon compounds found naturally underground. The liquid form of petroleum is called crude oil. Petroleum can be processed (refined) into a number of useful products including asphalt, diesel fuel, fuel oil, gasoline, jet fuel, lubricating oil, and plastics. Photosynthesis - The process by which green plants use sunlight to produce carbohydrates such as glucose, other nutrients, and oxygen from simple compounds such as water and carbon dioxide. In energy terms, photosynthesis converts solar energy into chemical potential energy that is in carbohydrates. Photovoltaic cell - A device that converts solar energy directly into electricity. For example, photovoltaic cells provide electricity for handheld calculators, watches, battery chargers, homes, and satellites. Photovoltaics - Of, or related to, the use of photovoltaic (solar) cells for producing electricity. See Photovoltaic cell. Potential energy - The energy in matter due to its position or the arrangement of its parts. Forms of potential energy include chemical, elastic, electrical (electromagnetic), gravitational, nuclear, and thermal energy. Potential energy is often referred to as "stored" energy. Some scientists and energy educators avoid the word stored because it might lead to the misunderstanding that energy is a substance. Click here to see further information about this and other possible energy misconceptions. Power - 1. The rate at which energy is transferred or converted per unit of time. 2. The rate in which work is done. See Horsepower, Kilowatt, Megawatt, Watts for units of power. Power Plant - 1. A human-made industrial system composed of machinery, equipment, and structures designed to convert various energy resources into electricity, usually on a large scale. Examples include coal-fired and nuclear power plants and hydroelectric dams. 2. Any human-made equipment or system that produces power, including the structure that contains it. Primary consumer - An organism, such as an animal, that feeds on plants or other producers; an herbivore. See Herbivore. Primary energy source - Source of energy either found in nature, such as the sun, coal, and oil. Producer - An organism, such as a plant or bacterium, that uses solar or chemical energy to manufacture the nutrients and organic compounds it needs from simple inorganic compounds. See Photosynthesis. Rate - The cost per unit of electricity or natural gas charged to a utility customer. Examples of rates include $0.60 per therm for natural gas and $0.70 per kilowatt-hour for electricity. Reading date - The date when a meter reader collects consumption information from an electric or natural gas meter. Renewable energy resource - Energy resource that can be quickly replenished. Certain renewable resources will always be available no matter how they are used (e.g., solar energy), while other renewable resources can be depleted when their rate of use exceeds their rate of replacement (e.g., wood). Resistance - The opposition of electric current by a material or electrical device. Electrical energy is converted into thermal and other forms of energy when work is done by a current to overcome a resistance. Respiration - Process by which the cells of organisms use oxygen to break down carbohydrates and other nutrients to release energy and produce carbon dioxide and water as byproducts. Secondary Consumer - An organism, such as a carnivore, that feeds only on primary consumers. See Carnivore, Primary consumer. Secondary energy source - Energy resource that is produced from a primary energy resource using technology (e.g., electricity produced from solar energy by photovoltaic cells). Second Law of Thermodynamics - 1. Each time energy is converted from one form to another, some of the energy is always degraded to a lower-quality, more dispersed, less useful form. 2. No system can convert energy from one form to another useful for with 100 percent efficiency. 3. Energy cannot be spontaneously transferred from a cold body to a hot body. 4. The entropy of a system increases over time. Solar cell - See Photovoltaic cell. Solar energy - Energy transferred from the sun to Earth in the form of electromagnetic radiation. Sound - Mechanical energy vibrations transmitted as waves through a solid, liquid, or a gas that can be detected by the human ear. Sound energy - See Sound. Standby energy - See Leaking electricity. Stored energy - See Potential energy. Switch - A device used to open or close an electric circuit or to divert electric current from one part of a circuit to another. System - 1. A group of interacting, interrelated, or interdependent parts made up of matter and energy that form a complex whole. 2. Anything that uses matter and energy to organize, maintain, or change itself (e.g., the sun, a glass of water, a frog, a city). Temperature - The level or degree of thermal energy in a substance, an object, or the surrounding environment as measured on a standard scale. In other words, temperature refers to whether something is hot or cold. It is the measurement of how fast the molecules are moving back and forth. Therm - (pl. Therms) A unit describing the energy contained in natural gas. One therm equals 100,000 Btu. See Btu. Thermal energy - The total internal kinetic and potential energy of an object due to the random motion of its atoms and molecules. An object that feels hot has more thermal energy inside it than it does after it has cooled down. Although technically incorrect, the word "heat" is often used to mean thermal energy. See Heat. Trophic level - A feeding level in a food chain in which an organism belongs. For example, producers (e.g., plants) are members of the first trophic level. See Consumer, Producer. Turbine - A machine that converts the kinetic energy of a moving fluid (e.g., pressurized steam) into mechanical energy (the rotating motion of a shaft). Volt - (abbrev. V; pl. Volts) A unit of voltage (potential difference). One volt is equal to performing one joule of work to move or separate one coulomb (6.25 x 1,018) of electrons. Water cycle - A biogeochemical cycle in which water is used, collected, distributed, and exchanged between organisms and Earth's environment. Watt - (abbrev. W; pl. Watts) - A unit of power. One watt equals the production or use of one joule of energy per second. See Joule, Kilowatt, Megawatt, Power. Wind - The movement and circulation of Earth's atmosphere near its surface; moving air. Wind generator - A generator specifically designed to convert the kinetic energy in wind into electrical energy (electricity). Work - The transfer of energy from one object or
system to another by applying a force over a distance. The formula for
work is
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