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The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires. [1] The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). [2] A fire naturally occurs when the elements are present and combined in the right mixture. [3]
A short piece of fire hose, usually 10 to 20 feet (6.1 m) long, of large diameter, greater than 2.5 inches (64 mm) and as large as 6 inches (150 mm), used to move water from a fire hydrant to the fire engine, when the fire apparatus is parked close to the hydrant. Solid stream A fire-fighting water stream emitted from a smooth-bore nozzle.
See also fire tetrahedron for the currently used model in firefighting. Fire wall: Building structure designed to delay horizontal spread of a fire from one area of a building to another; often regulated by fire code and required to have self-closing doors, and fireproof construction.
Fire was one of many archai proposed by the pre-Socratics, most of whom sought to reduce the cosmos, or its creation, to a single substance. Heraclitus (c. 535 BCE – c. 475 BCE) considered fire to be the most fundamental of all elements. He believed fire gave rise to the other three elements: "All things are an interchange for fire, and fire ...
The creation of sparks from metals is based on the pyrophoricity of small metal particles, and pyrophoric alloys are made for this purpose. [2] Practical applications include the sparking mechanisms in lighters and various toys, using ferrocerium; starting fires without matches, using a firesteel; the flintlock mechanism in firearms; and spark testing ferrous metals.
This glossary of chemistry terms is a list of terms and definitions relevant to chemistry, including chemical laws, diagrams and formulae, laboratory tools, glassware, and equipment. Chemistry is a physical science concerned with the composition, structure, and properties of matter , as well as the changes it undergoes during chemical reactions ...
In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron.The bond angles are arccos(− 1 / 3 ) = 109.4712206...° ≈ 109.5° when all four substituents are the same, as in methane (CH 4) [1] [2] as well as its heavier analogues.
Four flattened tetrahedra are joined to the triangular faces of the envelope, and connected to the central tetrahedron via 4 radial edges. These are the images of the remaining 4 tetrahedral cells. Between the central tetrahedron and the 4 hexagonal faces of the envelope are 4 irregular truncated tetrahedral volumes, which are the images of the ...