Candle
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A close-up image of a candle showing the wick and the various regions of the flame. Note the truncated wick being consumed at the lower-right edge of the flame. |
A
candle is a
light source usually consisting of an internal
wick which rises through the center of a column of solid
fuel. Prior to the mid 19th century, the majority of candles were
tallow (a byproduct of beef fat rendering). The fuel now is nearly always some form of
wax, with
paraffin wax being the most common. Soy and vegetable-based candles are also available, however.
Prior to the candle being ignited, the wick is saturated with the fuel in its solid form. The heat of the
match or other flame being used to light the candle first melts and then vaporizes a small amount of the fuel. Once vaporized, the fuel combines with
oxygen in the atmosphere to form a
flame. This flame then provides sufficient heat to keep the candle burning via a self-sustaining chain of events: the heat of the flame melts the top of the mass of solid fuel, the liquified fuel then moves upward through the wick via
capillary action, and the liquified fuel is then vaporized to burn within the candle's flame.
The burning of the fuel takes place in several distinct regions (as evidenced by the various colors that can be seen within the candle's flame). Within the bluer, hotter regions,
hydrogen is being separated from the fuel and burned to form
water vapor. The brighter, yellower part of the flame is the remaining
carbon soot being oxidized to form
carbon dioxide.
As the mass of the solid fuel is melted and consumed, the candle grows shorter. Portions of the wick that are not evaporating the liquid fuel are, ideally, consumed in the flame, limiting the exposed length of the wick and keeping the temperature and rate of fuel consumption even. Some wicks required manual trimming with
scissors or a wick trimmer for even burning, but these are rarely found in modern candles.
Candles were developed independently in many countries. The
Egyptians and
Cretans made candles from
beeswax, as early as 3000 BC. Early candles were made from various forms of natural fat, tallow, and wax. In the 18th century,
spermaceti, an oil produced by the
sperm whale, was used to produce superior candles. Late in the 18th century,
colza oil and
rapeseed oil came into use as much cheaper substitutes. Paraffin was first distilled in 1830, and revolutionized candle-making, as it was an inexpensive material which produced high-quality, odorless candles that burned reasonably cleanly. The industry was devastated soon after, however, by the distillation of
kerosene (confusingly also called
paraffin oil or just
paraffin). This excellent fuel for
lamps relegated candles to their current status as primarily decorative items.
Prior to the domestication of
electricity, candles were a common source of lighting, before, and later in addition to, the
oil lamp. Due to local availability and the cost of resources, for several centuries up to the
19th century candles were more common in northern
Europe, and
olive oil lamps more common in southern Europe and around the
Mediterranean Sea. Makers of candles were known as
chandlers.
Today, candles are usually used for their aesthetic value, particularly to set a soft, warm, or romantic ambience, and for emergency lighting during electrical
power failures.
Scented candles are common in
aromatherapy. Small candles are often placed on
birthday cakes.
Religion
Candles are used in the
religious ceremonies of many different faiths.
Buddhism
See
Ubon Ratchathani Candle Festival.
Christianity
In
Christianity, candles are commonly used in
worship both for decoration and ambiance, and as symbols that represent the light of
God, or specifically the light of
Christ. Candles are often placed on the
altar.
Votive candles may be lit as an accompaniment to
prayer. Candles are lit by
worshippers in front of
icons in
Orthodox and other churches. In some churches, a special candle known as the
Paschal candle specifically represents Christ, and is lit only at
Easter and
baptisms.
In some Christian denominations, the day of
Candlemas marks the end of the season of
Epiphany. On this day, the presiding priest blesses all the candles to be used in worship for the following year.
Candles were traditionally used to light up
Christmas trees before the advent of electric lights. They are still, even today, commonly used to decorate Christmas trees in
Denmark and other European countries. They are also used in
Advent wreaths.
In
Sweden (and other
Scandinavian countries),
St. Lucia Day is celebrated on
December 13 with the
crowning of a young girl with a ring of candles.
Judaism
In
Judaism, candles are traditionally lit on Friday evening at the start of the weekly
Sabbath celebration, and Saturday night during the
Havdalah ritual, which ends the Sabbath. The
Jewish
holiday of
Hanukkah, also known as the Festival of Lights, is celebrated by lighting a candle in a special candelabrum (
menorah) each night during the eight-day holiday to commemorate the dedication of the altar in the
Temple in Jerusalem. Candles are also used in remembering a deceased loved one, especially on their
Yahrzeit, the anniversary of their death according to the
Hebrew calendar, when a 24-hour candle is lit. Similarly, on Yom HaShoah, a day of remembrance for all those who perished in the
Holocaust, candles are lit to honor the victims.
Kwanzaa
Candles are also used in celebrations of
Kwanzaa, which is an
African American holiday which runs from
December 26 to
January 1.
Humanism
For
Humanists,
skeptics, and
nontheists (and particularly
secular humanists), candles have become a symbol of the light of
reason or
rationality. This association was inspired by
Carl Sagan, who subtitled his 1997 book
The Demon-Haunted World with
Science as a Candle in the Dark. The
Humanist festival of
HumanLight often features a candle-lighting ceremony.
Wicca
In
Wicca and related forms of
Neopaganism, candles are frequently used on the altar to represent the presence of the God and Goddess, and in the four corners of a ritual circle to represent the presence of the four elements. When used in this manner, lighting and extinguishing the candles marks the opening and closing of the ritual. Candles are also frequently used by Wiccans and other Neopagans for
magical and meditative purposes.
Timekeeping
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An Advent candle burning on the fourth day of December. |
With the fairly consistent and measurable burning of a candle, a common use was to tell the
time. Candles designed for this purpose might have time measurements, usually in hours, marked along the wax. The
Sung dynasty in China (960â€"1279) used candle-clocks. By the 18th century, candle-clocks were being made with weights set into the sides of the candle. As the candle melted, the weights fell off and made a noise as they fell into a bowl. A form of candle-clock was used in coal-mining until the twentieth century.
In the days leading to Christmas some people burn a candle a set amount to represent each day, as marked on the candle. Candles used in this way are called
Advent candles, although this term is also used to refer to the candles which decorate an
Advent wreath.
Candles can be made of
paraffin (a byproduct of
petroleum refining),
stearin (now produced almost exclusively from palm waxes),
beeswax (a byproduct of
honey collection),
gel (a mixture of
resin and
mineral oil), some plant waxes (generally palm,
carnauba,
bayberry, or soy), or
tallow (rarely used since the introduction of affordable wax alternatives). Candles are produced in various colors, shapes, sizes and scents. The most basic production method generally entails the liquification of the solid fuel by the controlled application of heat. This liquid is then poured into a mold to produce pillar candles, a fireproof jar to produce container candles, or a wick is repeatedly immersed in the liquid to create a dipped taper. Often,
fragrance oils are added to the liquid wax prior to pouring. Natural scents, in the form of
essential oils, can be used, but these are usually only found in premium, small-run candles. Candles may also be colored by the addition of some sort of coloring agent. In practical terms this is almost always an
aniline-based dye, although pigments can be used in some circumstances.
A candle typically produces about 13
lumens of
visible light and 40
watts of
heat [
1], although this can vary depending primarily on the characteristics of the
candle wick. For comparison, note that a 40 watt
incandescent light bulb produces approximately 500 lumens for the same amount of power. The modern
SI unit of
luminous intensity, the
candela, was based on an older unit called the
candlepower, which represented the luminous intensity emitted by a candle made to particular specifications (a "standard candle"). The modern unit is defined in a more precise and repeatable way, but was chosen such that a candle's luminous intensity is still
roughly one candela.
It is commonly believed that candles made of
beeswax and/or
soy burn more cleanly than
petroleum based
paraffin waxes. However highly-refined paraffin wax will burn as or more cleanly (with regards to particulates created during combustion) than natural waxes. The type of wick and inclusion of any scents and/or dyes have a much greater impact on the release of volatile compounds, particulates, and soot. Any of these will increase the amount of particulates put into the air by any candle regardless of construction materials. The cleanest burning candles will therefore be unscented, undyed, and well constructed candles burning in a draft free area.
Black Soot Deposition (BSD) can be a concern to those who frequently burn candles indoors and is also referred to as ghosting, carbon tracking, carbon tracing, and dirty house syndrome. Soot can be produced when candles do not burn the wax fuel completely. Scented candles are the major source of candle soot deposition. Trimming candle wicks to one fourth of an inch is recommended to keep soot production at a minimum. A flickering flame will produce more soot, therefore candles should be burned in an area free from drafts. (see http://web.ksl.com/dump/news/cc/series/candepa.htm for more details)
|
This candle holder uses a spike to keep the candle up. |
Decorative candle holders, especially those shaped as a pedestal, are called
candlesticks; if multiple candles are held, the term
candelabrum is also used. The root form of
chandelier is from the word for candle, but now usually refers to an electric fixture. The word
candelier is sometimes now used to describe a hanging fixture designed to hold multiple candles.
Many candle holders use a friction-tight socket to keep the candles upright. In this case, a candle that is slightly too wide will not fit in the holder, and a candle that is slightly too narrow will wobble. Traditionally, candles and candle holders were made in the same place, so they were appropriately sized, but
international trade has combined modern candles with existing holders, which makes ill-fitting candles more common.
Electric candle warmers are now being sold so that candle wax can be melted to release the fragrance without requiring an open flame.
Candles are a major cause of damaging fire in households.
A former worry regarding the safety of candles was that a
lead core is used in the wicks in order to keep the wicks upright in container candles. Without a stiff core, the wicks of container candles would sag and drown in the deep wax pool. Concerns rose that the lead in these wicks would vaporize during the burning process, releasing lead vapours - a known health and developmental hazard. Lead core wicks have not been common since the
1970s: some candles may still be found to have lead core wicks, but these are extremely rare. Most metal-cored wicks use
zinc or a zinc
alloy. Wicks made from specially treated paper and cotton are also available. These wicks eliminate the need for metal in the wick.
*
Candela, the
SI base unit for
luminous intensity*
Rushlight*
List of light sources*
Timeline of lighting technology*
Candle and Soap Making at About.com*
Are soy candles cleaner burning?*
National Candle Association of the
U.S.
