火
在Yahoo!知識中，看見一個很好的問題，轉貼如下：
火是固體、液體還是氣體？
Fire is not a state of matter: <----main point.
rather, it is an exothermic chemical reaction accompanied by intense heat released during a rapid oxidation of combustible material. Fire may be visible as the brilliant glow and flames and may produce smoke.
Fires start when a flammable or combustible material with adequate supply of oxygen or other oxidizer is subjected to enough heat. The common fire-causing sources of heat include a spark, another fire (such as an explosion, a fire in the oven or fireplace, or a lit match, lighter or cigarette) and sources of intense thermal radiation (such as sunlight, a flue, an incandescent light bulb or a radiant heater). Mechanical and electrical machinery may cause fire when combustible materials used on or located near the equipment are exposed to intense heat from Joule heating, friction or exhaust gas. Fires can sustain themselves by the further release of heat energy in the process of combustion and may propagate, provided there is continuous supply of oxygen and fuel. Fires may become uncontrolled and cause great damage to and destruction of human life, animals, plants and property.
Fire is extinguished when any of the elements of so-called fire triangle—heat, oxygen or fuel—is removed. The unburnable solid remains of fire are called ash.
Flames can conduct electricity, as a small portion of any fire is ionized. This has been demonstrated in the laboratory and also in large wildfires that occur in the vicinity of power lines. This ability to conduct electricity is due to its partially plasmaic nature.
these all are the properties of fire.
參考資料: http://en.wikipedia. org/wiki/Fire
沒有留言:
張貼留言