Thermal Effects 4


Anatomy of a fire

Combustion is the self-sustaining process of rapid oxidation of a fuel being reduced by an oxidizing agent along with the evolution of heat and light. Fires are defined by their physical characteristics. They may vary from very slow oxidation, as in rusting, to very fast oxidation, such as detonations and explosions.

Nuclear Heat Energy

Nuclear Fission and Fusion – The heat generated by either the splitting or combining of atoms.

oxidation–reduction reaction

Also called redox reaction any chemical reaction in which the oxidation number of a participating chemical species changes. The term covers a large and diverse body of processes. Many oxidation–reduction reactions are as common and familiar as fire, the rusting and dissolution of metals, the browning of fruit, and respiration and photosynthesis—basic life functions.

Chemical vs nuclear burning

Question – How does the sun keep burning when there is no
oxygen? My student asked me this. I talked with him about nuclear
reactions. He looked up fire in the World Book. He found that fire
needs oxygen, fuel and heat. Can you explain this? Thank you.

Rise P., teacher, Bloomington, IN
The definition that you were looking at is, narrowly, chemical burning in
air. Fire, more formally, is the phenomenon of atomic (molecular)
recombination that is manifest by a new product and electromagnetic
radiation. Chemical combustion just rearranges the atoms from parent
material(s) to product material(s). The radiation given off is often light
or infra-red (heat). Note that this does not require oxygen. Oxidation
reactions are remarkably common, but by no means the only way to do this.

In nuclear burning, the atoms themselves are combined to create new and
different atoms. Nuclear burning does not require oxygen. The main
nuclear burning that is happening on the sun is a hydrogen-hydrogen
process, forming helium. There are other processes, too, but this is the
main one.

Spontaneous combustion

Comment: it is easy to see how a firestorm started in Hiroshima.

Melted ammunition

Photo: WTC Building 6 (U.S. Customs) viewed from the roof of a federal building.

Comment: Even in the WTC 6 building that was not hit by a plane, metal stored within it (ammunition) melted and fused into a ball such was the intensity of the heat from the WTC Twin Towers.

Photo: A bullet ball located near WTC-6, which housed a firing range. More than 1 million pounds of ammunition were lost.

WTC Building 6 housed several federal agencies, primarily U.S. Customs (Photo 11). The third floor—now largely inaccessible—contained a firing range. More than 1.2 million rounds of ammunition were stored on this level, as was a vault used to store other explosives and weapons. A seizure vault was also on the third floor; it contained evidence (such as drugs, cash and evidence files) seized during Customs operations. Final status: At great personal risk, Customs officials, the FBI and contractor representatives located and removed the criminal evidence from Building 6 during the fourth week of the effort. The ammunition was finally located on Oct. 24, 2001, melted together into large “bullet balls” that were extremely dangerous to handle and dispose of properly (Photo 12). At one point, a discharge of a bullet, due to the immense heat in the area, caused a shrapnel wound to the face of one worker.

Hot attack (instant corrosion) on metal

Pictures of corroded metal

The spire

Red-hot I-beam in WTC 5

“I walked over past where Building 5 (of the Trade Center complex) was standing. The pile of debris was five-and-a-half stories high. I walked three-and-a-half blocks before I found the end of it,” Burnett said.

He joined two city sanitation officials exploring the lower parking level. One dark room contained a bright red light — an I-beam still red-hot from the fire that collapsed the building.

Instant rusting = bomb

Nuclear Glow

VIDEO: Nuclear glow   Dailymotion

Nuclear glow during the blow-up of the North Tower.

Spire on top of the North Tower aspirating 

VIDEO: View of the Spire    Dailymotion

At 00:50, the spire on top of the North Tower can be seen to aspirate.

Good lord! – North Tower collapsing and glow

VIDEO: Good lord! North Tower collapsing  Dailymotion