Power supplied by machines.
metals utilized to make products other than iron and steel.
A source of energy that is a finite supply capable of being exhausted.
gas that absorbs ultraviolet solar radiation, found in the stratosphere, a zone between 15 and 50 kilometers (9 to 30 miles) above Earth's surface.
Passive Solar Energy Systems
Solar energy that collects energy without the use of mechanical devices.
An atmospheric condition formed through a combination of weather conditions and pollution, especially from motor vehicle emissions.
Solar energy cells, usually made from silicon, that collect solar rays to generate electricity.
Addition of more waste than a resource can accommodate.
The amount of energy in deposits not yet identified but thought to exist.
Maintenance of a resource in its present condition, with as little human impact as possible.
The amount of a resource available in discovered deposits
Particles from a nuclear reaction that emit radiation; contact with such particles may be harmful or lethal to people and must therefore be safely stored for thousands of years.
The process of collecting used materials that would otherwise be thrown away and turning them into raw materials for new uses.
A resource that can be replaced when needed.
A substance in the environment that is useful to people, is economically and technologically feasible to access, and is socially acceptable to use.
A place to deposit solid waste, where a layer of earth is bulldozed over garbage each day to reduce emissions of gases and odors from the decaying trash, to minimize fires, and to discourage vermin.
Farming methods that preserve long-term productivity of and and minimize pollution, typically by rotating soil restoring crops with cash crops and reducing inputs of fertilizer and pesticides.