An ember, also called a hot coal, is a

hot Hot or the acronym HOT may refer to: Food and drink *Pungency, in food, a spicy or hot quality *Hot, a wine tasting descriptor Places * Hot district, a district of Chiang Mai province, Thailand **Hot subdistrict, a sub-district of Hot Distric ...

lump of smouldering solid

fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but ...

, typically

glowing Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluo ...

, composed of greatly heated

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

, or other

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...

-based material. Embers (hot coals) can exist within, remain after, or sometimes precede, a

fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition ...

. Embers are, in some cases, as hot as the fire which created them. They radiate a substantial amount of heat long after the fire has been extinguished, and if not taken care of properly can rekindle a fire that is thought to be completely extinguished and can pose a fire hazard. In order to avoid the danger of accidentally spreading a fire, many campers pour water on the embers or cover them in dirt. Alternatively, embers can be used to relight a fire after it has gone out without the need to rebuild the fire – in a conventional

fireplace A fireplace or hearth is a structure made of brick, stone or metal designed to contain a fire. Fireplaces are used for the relaxing ambiance they create and for heating a room. Modern fireplaces vary in heat efficiency, depending on the design. ...

, a fire can easily be relit up to 12 hours after it goes out, provided that there is enough space for air to circulate between the embers and the introduced fuel. They are often used for cooking, such as in

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, cal ...

barbecue Barbecue or barbeque (informally BBQ in the UK, US, and Canada, barbie in Australia and braai in South Africa) is a term used with significant regional and national variations to describe various cooking methods that use live fire and smoke t ...

s. This is because embers radiate a more consistent form of heat, as opposed to an open fire, which is constantly changing along with the heat it radiates. An ember is formed when a fire has only partially burnt a piece of fuel, and there is still usable chemical energy in that piece of fuel. This happens because the usable chemical energy is so deep into the center that air (specifically oxygen) does not reach it, therefore not causing

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combusti ...

(carbon-based fuel + O₂ → CO₂ + H₂O + C + other chemicals involved). It continues to stay hot and does not lose its thermal energy quickly because combustion is still happening at a low level. The small yellow, orange and red lights often seen among the embers are actually combustion; the combustion is just not happening at a fast enough rate to create a

flame A flame (from Latin ''flamma'') is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction taking place in a thin zone. When flames are hot enough to have ionized gaseous components of sufficient density they ...

. Once the embers are completely 'burned through', they are not carbon as is commonly believed (carbon burns, and is not normally left behind), but rather various other oxidized minerals like calcium and phosphorus. At that point they are called

ashes Ashes may refer to: *Ash, the solid remnants of fires. Media and entertainment Art * ''Ashes'' (Munch), an 1894 painting by Edvard Munch Film * ''The Ashes'' (film), a 1965 Polish film by director Andrzej Wajda * ''Ashes'' (1922 film), a ...

. Embers play a large role in forest fires, wildland fires or wildland urban interface fires. Because embers are typically burnt leaves and thus small and lightweight, they can easily become airborne. During a large fire, with the right conditions, embers can be blown far ahead of the fire front, starting spot fires several kilometres/miles away. A number of practical measures can be undertaken by homeowners to reduce the consequences of such an " ember attack" that bombards especially wooden structures and starts property fires.

References

External links

* {{Firelighting Fire ru:Горение#Тление