Glossary
Biogeochemical Cycles
The pathways by which chemical elements, such as carbon, nitrogen, and water, move through the biotic and abiotic components of Earth. Energy is essential for driving these movements.
Example:
The carbon biogeochemical cycle relies on solar energy for photosynthesis, which fixes atmospheric carbon into organic compounds.
Chemical Energy
Energy stored in the bonds of molecules. This energy is released when chemical reactions break or form new bonds.
Example:
The food we eat contains chemical energy that our bodies convert into kinetic energy for movement and metabolic processes.
Climate
Long-term weather patterns and conditions in a region, primarily driven by solar energy. It influences temperature, precipitation, and global atmospheric circulation.
Example:
Changes in solar radiation can significantly impact Earth's climate, leading to shifts in global temperatures and ice cover.
Elastic Energy
Energy stored in an object when it is stretched, compressed, or deformed. This energy is released when the object returns to its original shape.
Example:
A compressed spring in a toy stores elastic energy, which is released to propel the toy forward.
Electrical Energy
Energy resulting from the movement of electrons. It is a highly versatile form of kinetic energy used to power many modern devices.
Example:
Power lines transmit electrical energy from generation plants to homes and businesses.
Energy
The ability to do work, causing movement, heat, or change in matter. It is a fundamental concept driving all processes in Earth systems.
Example:
The sun's energy powers photosynthesis, allowing plants to grow and form the base of most food webs.
Energy Efficiency
The measure of how much useful energy is produced from the total energy input. Higher efficiency means less energy is wasted as heat or other unusable forms.
Example:
Replacing old incandescent bulbs with LED lights significantly improves energy efficiency in a home, reducing electricity consumption.
Energy Transformations
The process by which energy changes from one form to another. Energy is never created or destroyed, only transformed.
Example:
In a car engine, the chemical energy in gasoline undergoes energy transformations into thermal energy, then mechanical energy to move the vehicle.
Environmental Impacts (of energy)
The consequences that energy production, consumption, and waste have on natural ecosystems, climate, and human health. These can be positive or negative.
Example:
Burning fossil fuels for energy has significant negative environmental impacts, including air pollution and greenhouse gas emissions.
Exajoule (EJ)
A unit of energy equal to one billion gigajoules, or 10^18 joules. It is used to measure very large-scale energy consumption or production.
Example:
The total annual energy consumption of a large country can be measured in Exajoules.
Gigajoule (GJ)
A unit of energy equal to one billion (10^9) joules. It is used to measure larger quantities of energy.
Example:
A small industrial process might consume several Gigajoules of energy per day.
Gravitational Energy
Energy stored in an object due to its position in a gravitational field, specifically its height above a reference point.
Example:
Water held behind a dam possesses immense gravitational energy, which is converted to kinetic energy as it falls through turbines.
Joule (J)
The basic international unit of energy. It is a measure of work done or heat transferred.
Example:
A single Joule is a relatively small amount of energy, roughly equivalent to the energy needed to lift a small apple one meter.
Kinetic Energy
The energy of motion. Any object or substance that is moving possesses kinetic energy.
Example:
A river flowing rapidly downstream possesses significant kinetic energy, which can be harnessed by hydroelectric dams.
Mechanical Energy
The energy of moving objects or substances. It is a form of kinetic energy associated with macroscopic motion.
Example:
Wind turbines convert the mechanical energy of moving air into rotational energy to produce electricity.
Nuclear Energy
Energy stored within the nucleus of an atom. It is released during nuclear reactions like fission or fusion.
Example:
In a nuclear power plant, nuclear energy is released from uranium atoms through fission to heat water and produce steam.
Potential Energy
Stored energy that an object possesses due to its position, condition, or composition, waiting to be released.
Example:
A large boulder perched precariously on a cliff edge has significant potential energy due to its elevated position.
Quad
A unit of energy primarily used in the United States, equal to one quadrillion (10^15) BTUs, or approximately 1.055 Exajoules. It represents a very large amount of energy.
Example:
The U.S. annual energy budget is often discussed in terms of Quads.
Radiant Energy
Energy that travels in waves, such as light or electromagnetic radiation. It is a form of kinetic energy.
Example:
Solar panels capture radiant energy from the sun and convert it into usable electricity.
Renewable vs. Non-Renewable Energy
A classification of energy sources based on their ability to replenish naturally. Renewable sources regenerate quickly, while non-renewable sources are finite and deplete over time.
Example:
Solar power is a renewable energy source, whereas coal is a non-renewable energy source.
Sound Energy
Energy that travels in waves through a medium, caused by vibrations. It is a form of kinetic energy.
Example:
The loud roar of a waterfall demonstrates the powerful sound energy created by the impact of water.
Tectonic Activity
Processes driven by Earth's internal heat, involving the movement of lithospheric plates. This activity causes phenomena like earthquakes and volcanoes.
Example:
The immense heat from Earth's core drives tectonic activity, leading to the formation of mountain ranges and oceanic trenches.
Thermal Energy
Heat energy resulting from the random motion of atoms and molecules. It is a form of kinetic energy.
Example:
Geothermal power plants tap into Earth's internal thermal energy to generate electricity.