Glossary

absorption
process of light energy changing into heat energy occurring when light falls on an object and is taken into it (can be compared to a sponge soaking up water)

active solar energy
solar energy provided by equipment; examples: PV cells, solar collectors

alternative fuel
any fuel for vehicles other than petroleum-based fuels
examples: solar, electric, compressed natural gas, propane, alcohol, and hydrogen

biomass
renewable source of energy that has been stored as plant and animal material; producing fuels from living materials or decayed waste materials; examples: manure, wood, compost, ethanol from corn, methane from landfills

calorie
amount of heat energy needed to raise the temperature of 1 kilogram of water 1o C

carbon dioxide (CO2)
colorless, odorless, non-poisonous gas normally present in air; vital to plant function

Celsius (C)
temperature scale used in the metric system in which water freezes at 0 degrees and boils at 100 degrees

central receiver system
high-temperature solar thermal system that uses mirrors (heliostats) to reflect solar energy atop a tower to heat fluid

concentrator
a system that focuses the sun on an area to obtain a higher temperature

conduction
movement of heat or cold through materials that are solid

current
flow of electric charge

DC meter
device used to measure direct current energy output

desalinization
process of removing salt and other chemicals and minerals

direct radiation
sunlight that hits at least one surface of an object

dish system
high-temperature solar thermal system that uses a parabolic tracking concentrator to focus the sun's rays onto a receiver

earth materials
substances that make up or come from the earth; examples: rocks, water, soil, sand, minerals

electricity
flow of electrons

energy source
object or material that produces energy by changing it from one source to another

energy transfer
transformation from one type of energy into another; example: light energy changing into heat energy resulting in temperature change

evaporation
process of changing into vapor

Fahrenheit
Measurement scale on which under standard atmospheric pressure the boiling point of water is at 212 degrees above the zero of the scale, the freezing point is at 32 degrees above zero

fossil fuels
nonrenewable energy sources that come from fossilized plants and animals and cannot be replenished; examples: coal, oil, natural gas

geothermal
renewable source of energy from the internal heat in the core of the earth;
examples: hot springs, steam, volcanoes

geothermal energy
harnessing heat and steam generated below Earth's surface

gnomon
sundial; a stick or pole placed in the ground

heliostat
a sun-tracking mirror

high-temperature solar thermal system
dishes, troughs, and other concentrators that convert the sun's heat into both electricity and hot water at the same time

hydropower
renewable source of energy that comes from water and is harnessed
to produce electricity

indirect radiation
sunlight that bounces from one surface to another

infrared light
invisible radiation or light contiguous to red in the visible spectrum;
light energy we feel as heat

insulation
process of keeping heat or cold in one place and preventing it from escaping with little or no air movement

load
a device to which power is delivered

molecule
the smallest particle of a substance that retains the properties of the substance an is composed of one or more atoms

nonrenewable energy source
source of energy that is either unable to be replaced naturally or are naturally replaced very slowly; examples: fossil fuels (coal, oil, natural gas) and nuclear fuels (uranium).

nuclear energy
splitting radioactive uranium atoms to create heat energy

orientation
set in any definite position with reference to the points of the compass

oxygen
an element that at standard temperature and pressure is colorless, tasteless and odorless; required for nearly all combustion and in the cellular functioning of animals

parabolic reflector
concave mirror to focus and reflect the sun's rays

passive solar design
construction technique of using structural elements of a building to bring in heat in cold weather and deflect or vent heat in hot weather through the use of materials, coating, eaves, windows, landscape;
examples: north, south, east, west orientation, sun/shade, insulation

photovoltaic (PV)
the effect of producing electric current using light
photo: light
voltaic: producing direct electric current by chemical action

photovoltaic (PV) cell
device that converts solar energy directly into electricity

primary energy source
source of energy found or stored in nature; examples: biomass, coal, oil, natural gas, the sun, wind, water, nuclear power from radioactive substances, thermal power stored in the earth's interior and oceans, and potential energy from the earth's gravity

radiation
process of emitting energy in the form of waves or particles; sunlight is solar radiation

reflection
return of light from a shiny surface at an angle

reflector
shiny device used to alter the path of light; a mirror is a reflector

renewable energy resource
source of energy that is virtually inexhaustible and is naturally and quickly replenished; examples: solar, wind, hydropower (water), geothermal, and biomass

secondary energy source
source of energy produced from primary energy sources using technology; examples: production of electricity by burning coal, using photovoltaic cells to harness solar energy, producing alcohol/methane fuel from corn and other crops

solar (electric) cell
photovoltaic (PV) cell

solar energy
energy derived from the sun

solar oven
solar-powered device that is able to cook food

solar thermal energy
using the sun to heat water; the simplest type of solar technology

sun protection factor (SPF)
rating which determines how many times longer your skin can tolerate UV rays when sunscreen is applied. For example, if it takes you 5 minutes to burn and you use an SPF 15 sunscreen, it should take you 75 minutes to burn (5 minutes times 15 SPF equals 75 minutes)

trough system
high-temperature solar thermal system that focuses sunlight onto steel pipes or glass tubes to transfer heat into steam to power generators

ultraviolet (UV) light
invisible radiation or light just beyond violet in the visible spectrum

waves and tides
renewable sources of energy that use the force of ocean waves and tides

wind energy
renewable source of energy that uses wind to turn a windmill