Do not touch it without protection. Young children should not attempt this exercise without adult supervision. There are various ways in which the fire triangle can be broken or altered. One example of how the triangle can be broken can be done with a short candle and a jar. Light the candle and set it on a flat surface. After a short time, the candle will go out. This occurs because all of the oxygen inside the jar has been used up by the burning candle and no additional oxygen can get to the candle because of the jar.
Before you put the jar over the burning candle, you had all the ingredients necessary for combustion; heat from the match, fuel in the candle and oxygen from the air. Relight the candle. This time, take a pair of scissors and cut off the wick below the flame and remove the candle.
Again, the fire will go out after a short period when the rest of the wick that was left on the scissors is consumed. This time you had plenty of oxygen in the air but you removed the fuel. The same principle is used in fighting wildfires. Remove heat, oxygen or fuel and the fire goes out. In suppression of a wildfire, the objective is to stop combustion by removing or altering one or more sides of the triangle. Stages of combustion: flaming stages see pictures from lab.
Transition — fuel is partially consumed by combustion while flaming continues in portions of the fuel resulting in initiation of smoldering and smoke generation. David L. Heiserman, Exploring Chemical Elements and their Compounds. Navigation Bar. Heat allows fire to spread by drying out and preheating nearby fuel and warming surrounding air.
Fuel is any kind of combustible material. The moisture content determines how easily it will burn. Air contains about 21 percent oxygen, and most fires require at least 16 percent oxygen content to burn.
Oxygen supports the chemical processes that occur during fire. When fuel burns, it reacts with oxygen from the surrounding air, releasing heat and generating combustion products gases, smoke, embers, etc. That is how oxygen supports combustion. It does not burn up the cigarette as you may imagine. It only makes the cigarette burn hotter. Think of oxygen as a fertilizer for fire.
So what is this about oxygen being flammable? Also read: Is Water Flammable? Should You Be Worried? It is well known that in order for fire to occur, it takes three elements called the fire triangle. Firefighters know that in order to stifle put out a fire, you must remove one or more of the three elements.
If you were to smother the fire, hence removing the oxygen, it would eventually burn out. But if you remove the blanket too soon, the remaining heat would find more oxygen and reignite. The presence of oxygen in an area that is sufficiently heated, will cause a fire to become supported by the oxygen, but it is not burning; otherwise, we would call it fuel.
To complicate matters slightly, firefighters and scientists add a fourth dimension to the fire triangle, called the fire tetrahedron. A tetrahedron is a four-sided triangle which in this case adds a fourth element to the fire triangle. Free radicals are combinations of many flammable elements which also exacerbate the combustion process.
Among other techniques, they can be eliminated by a layer of dry chemical agents. The removal of free radicals can easily be accomplished in smaller fires. The production of smoke and its various elements call for large quantities of water, and effective application.
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