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  • Energy - a quantity that describes the ability to create useful or desirable change; cannot be created or destroyed but can change forms

    • Kinetic - the energy of motion, such as wind, the motion of an object, and more

    • Potential - stored energy, such as 

      • Chemical - energy stored in the form of chemical bonds

      • Thermal - energy released in the form of heat

      • Electrical - energy between charged particles (electrons)

      • Nuclear - energy stored in the nucleus of an atom required to hold together neutrons and protons

    • Light - energy in the form of electromagnetic radiation, like solar irradiation

    • Mechanical - the sum of kinetic and potential energy associated with physical movement, like turning a gear

  • Work - energy expended in the form of moving an object over a certain distance

  • Entropy - energy that is not available to do useful work, describes the disorder in a system 

  • Power - the rate at which energy is expended or work is done, in other words energy per amount of time

  • Primary energy source - energy that comes directly from natural resources. This can be a fuel (coal, crude oil) or a flow (wind, solar, hydro).

  • Secondary energy source - energy that has been converted from a primary energy source. Gasoline is an example of a secondary energy source, since it has been processed from crude oil through distillation.

  • Energy flow - Flows have energy associated with motion, and come from natural processes. Some examples include solar radiation, the movement of tides, wind, or water flowing downstream in a river.

  • Renewable energy - energy is replenished at an equal or higher rate than it is consumed.

  • Energy density - the amount of energy stored in fuels. Two ways to conceptualize energy density is the amount of energy per unit of volume and the amount of energy per unit of mass of a fuel. 

  • Electricity - movement of charged particles such as electrons. An external energy source is applied to drive the flow of electrons through a circuit, but the electrons themselves are never consumed. Electricity must be used immediately once generated.

    • Current - rate of flow of electric charge through a circuit

      • Direct current (DC) - the simple flow of electrons in one direction through a wire

      • Alternating current (AC) - electrons alternate their direction of movement through a wire, moving back and forth

    • Voltage/potential - energy needed to move electric charge from one point to another through a circuit, electric pressure

  • Power grid - system designed to transport electricity 

  • Fuel - chemical compounds that have energy stored in their chemical bonds

    • Fossil fuel - hydrocarbon compounds formed from dead plants and animals over millions of years compressed in the earth

    • Renewable fuel - fuels that humans can make or harvest

  • Atom - particles that make up all the material in the world 

    • Nucleus - center of an atom, composed of neutrons and protons

    • Neutron - neutrally charged particle

    • Proton - positively charged particle 

    • Electron - negatively charged particle

  • Nuclear Fusion - two nuclei of different atoms combine to form a larger nucleus of a new type of atom, releasing a large amount of energy in the process

  • Nuclear Fission - a large, unstable nucleus of an atom splits apart into smaller nuclei, releasing a large amount of energy in the process

  • Radioactivity - spontaneous decay of an unstable nucleus into a more stable nucleus, leading to the emission of high energy rays and particles. This is different from nuclear fusion or fission, since it is a much smaller relative change to the nucleus.

  • Chemical bond - the sharing of electrons between atoms, holding the two atoms together. Chemical bonds have an energy associated with them, and breaking a bond releases energy.

  • Silicon – a chemical element (Si) with the atomic number 14;  most prevalent in its silicon dioxide form (components of glass, sand); in its most purified form its properties make it ideal for use in solar cells and computer chips

  • Combustion - the reaction between a fuel (hydrocarbon) and oxygen which breaks chemical bonds and releases energy as heat. General combustion reaction:

    • Hydrocarbon fuel + oxygen → carbon dioxide + water + heat + other pollutants

  • Environmental Justice - a concept that calls to attention the increased exposure of certain communities to negative environmental hazards, particularly already marginalized communities.

  • Climate Justice - a framework that describes how people across the globe are disproportionately impacted by climate change.

Page last updated: November 20, 2022​

Key Definitions and Terms

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