9/11 Science Club! What Are Specific Heat and Heat-Energy Content?

They pulled it off by dumbing us down. Education and critical thinking are vital to democracy. Science is fun!


Specific heat can be defined as the amount of heat energy required to raise the temperature of one gram of a substance, such as wood or steel, by one degree C.

Heat content is the heat energy which can be generated by a given mass a substance.

A calorie is the amount of heat energy required to raise the temperature of one gram of water by one degree C.

Converting the energy unit calories to British Thermal Units (BTUs), and the mass unit of grams to pounds, some specific heats are:

aluminum: .22 BTU/lb.
copper: .09 BTU/lb.
iron: .11 BTU/lb.

For aluminum this means it requires .22 BTUs to raise the temperature of a pound of aluminum by one degree.

Some heat content values are:

wood: 7870 BTU/lb.
paper: 6500 BTU/lb.
gasoline: 19000 BTU/lb.

For wood this means a pound of wood can generate 7870 BTUs. A pound of gasoline can generate 19000 BTUs. Therefore gasoline contains more heat energy per pound than wood.

Discussion

On 9/11 it is argued that the fires did or did not reach sufficient temperatures to sufficiently weaken the steel to induce global collapse. But temperature is only one factor. The total heat content of the available fuel would have to be sufficient to raise the 95,000 tons of steel in the frame to a sufficient temperature, since steel is an excellent heat conductor and it would dissipate quickly to all parts of the steel frame. Steel is considered an ideal "heat sink."

In addition, a mechanically forced oxygen supply is required to burn fuel efficiently enough for it to reach its maximum burning temperature and deliver its maximum heat content. In order to make steel soft enough to be malleable, air must be pumped forcefully through the fuel with an instrument such as a bellows. A blast furnace gets its name from the air "blasted" forcefully with an air compressor through fuel such as coal.

In steel forming and forging, the ratio of coal or coke (refined coal) to steel required to make steel soft or to melt is anywhere from 1-to-3, to 1-to-2. This is high heat content fuel burning in an enclosed and insulated chamber at its maximum efficiency.

It is estimated that there were an average of 4 pounds per sq. foot of combustibles in the office space of the Twin Towers. There was 40,000 sq. feet of office space per floor. Therefore, the total amount of combustibles would be:

4 x 40,000 x 110 floors=17.6 million pounds of combustibles

17.6 million lbs=8,800 tons.

A full load of jet fuel for a 767 is about 80 tons, insignificant compared to the total amount of office combustibles.

Jet fuel is only kerosene, and has roughly the same heat content as burning plastics and office synthetics, and burns at about the same temperature in open air. Most of the kerosene blew out in the fireballs.

Therefore the available combustible fuel in one tower was 8,800 + 80= 8,880 tons

The total amount of structural steel in the towers was 95,000 tons, 35,000 tons of it in the core bundles.

Only a small number of the floors were on fire, and those were already going out by the time global destruction ensued. However, even making the most generous of assumptions, that the planes were fully loaded with kerosene, that there was no loss to the fireballs, that every bit of combustible fuel on every floor was burning white hot at maximum efficiency (as under a forced air supply) and burning as hot as coal in a ceramics-insulated blast furnace or foundry, the ratio of fuel to steel is still only 1-to-10, not 1-to-3 or 1-to-2, as the most efficient of blast furnaces or foundries requires.

Granting the still generous assumption that a full 20 floors were on fire at white hot, maximum efficiency as hot as coal would make the ratio of fuel-to-steel 1-to-50.

The plane hits themselves were insignificant. A 767 fully loaded weighs about 200 tons, whereas the mass of each tower which absorbed and dissipated the kinetic energy was about 500,000 tons. This is a weight ratio of 1-to-2500. Steel is much denser than aluminum and the planes were shredded on impact, as photographic evidence confirms.

Any damaged support columns would have resulted in load redistribution to remaining columns, of which there were 47 running continuously up the entire 110 floors.

This is why steel framed buildings do not, and have never, collapsed from fires. Steel is too strong, and open air fires do not burn hot enough, NOR IS THERE ENOUGH FUEL PRESENT WHICH CONTAINS SUFFICIENT HEAT ENERGY.

Please discuss, challenge scientific values, calculations, or assumptions. There is no such thing as a dumb question.

Shredded aircraft fuselage


Core backbone of tower under construction

 

Way too complex for American Idol watchers to comprehend but you're 100% correct in your premise, of course.

 

Who did it?

The Jews?

 

Concrete, for the time periods involved, is an effective insulator.


Steel (iron) and the aluminum frame of the aircraft will both become vaporized ions under the conditions present. The Iron will oxidize, then the aluminum vapor will react in the same way that thermite does, which is a highly exothermic reaction.


Consider how the missle frigate Shiefeld burned when hit in the Falklands war...


You're analysis is far from scientific, it just appears that way to those you can't really churn the numbers, and have no experience with fighting aircraft fires.

 

It wasn't cave dwellers with Walmart box cutters...

 

so very true.He is making wayyyyyyy too much since for the official conspiracy theory apologists to comprehened.hee hee.

 

your close.to be exact is was the ZIONISTS jews.they are not true jews.True jews are good people,they believe in juduism,the zionists jews do not.The evidence is ovwerwhlming that it was a joint CIA.MOSSAD operation.both these videos prove it.they are both a couple hours long but you will learn the truth if you watch them.

http://www.youtube.com/watch?v=GD_vwzjdTi4

http://www.youtube.com/watch?v=iGI4jfwOmOk

 

I thought all the Zionists got wiped out from Mussolini/Hitler/Stalin?

 

my god, this garbage has been debunked time and time again and shown to be nothing but horse BS. It has been shown by experts time and time again that the jetliners and fuel were enough to weaken the structures to the point of bringing the buildings down. There are detailed explanations of how this happened making these conspiracy theories look real silly. One of the funniest theories is that the jet fuel and jet impact had to somehow melt or weaken 95k tons of steel! LOL!!! this is the type of BS consporacy theorists latch onto...any man with half a brain would understand that all of the 95k tons of steel had to be weakened, only a fraction of this needed to be affected for the buildings to collapse.

here is a detailed explanation of what happened with the steel, educated yourselves:

http://www.youtube.com/watch?v=oXxynEDpwrA

 

The only thing that has been debunked is the "official" BS story. What they specifically say can't possible be correct. Lots of folks agree.
www.AE911TRUTH.COM

 

The damage to the tower from the crash, both crashes was significant though sustainable and without any other influences, would have been rebuildable. What is different about these buildings compared to other steel structures is the core shell construction. Approximately 60% to 70% of the load bearing structure was the core which was designed to bear the load even if the outer shell was breached. It did to a certain extent but there was considerable damage to at least one side of each core, which in itself would not have cause a collapse.

The structure was designed to have 2 hours of fire protection under normal circumstances with the fire retardant intact and the fire suppression system operational. Normal circumstances would have been a floor fire that could be fought by normal firefighting techniques. In each case, at least 5 floors were breached along with the fire suppression system and the fire retardant stripped from the mass of a 767 flowing through the floors as shredded aluminum and in the case of the fuel, a wall of hard hitting fluid and in some cases, steel and other components of the aircraft that were not aluminum like the landing gear and engines.

The fires themselves could have been survivable if normal firefighting techniques were available, but weren't due to the damage to most of the core stairwells and fire suppression system, so were not only un-fightable, but spread up and down from the impact zone as attested to by firefighters that reported back on radio but did not survive the collapse and the people that were able to escape.

Now for the core, a simple example is a three column core I I I, take out one of the outer columns and the bending moment would relieve the other side of much of it's load and concentrate the entire load on the center column. Design of a column load is always significantly lower than it's maximum load but none of the columns were designed to bear the complete load, which would be significantly over the maximum. Since there were more than 3 columns, the center columns could bear the load for some time unless other factors come to play like increased loads, bending moment, and heat.

This is where the fire comes in. First bear in mind that the fires had an oxygen source, with the damage from the aircraft along with blown out windows and more blowing out with the heat. The multitude of people jumping could not jump out of closed windows. The fuel was not the significant fuel for the fire but the catalyst for it's beginning. The remaining combustibles were the major source of fuel of which there was plenty from the furniture, to plastic, to paint, to carpeting, to thousands of pounds of paper. A fire burning inside the building would do two things, it would affect the so called "heat sink" of steel of the core. Iron is not a perfect heat sink but takes time to propagate heat throughout the other columns up and down and can only do that so fast, so the amount of heat it absorbs is localized to the immediate heat source. Iron only has to heat to about 1/2 of melting point before it starts to become plastic. Keep that in mind when you think about the distributed stresses caused by column removal and damage by the crash.

Next is the heat of affecting the outer shell. This would be an uneven heat affect since the shell facing outside of the building would be cool compared to the inner part of the shell facing the fires. This would produce a bending moment to the shell support columns which would add stress to the floor joist connections spanning between the outer shell and inner core. Now the floor connections were not welded but bolted to the outer shell and core. These would be subject to more sheer stress than they were designed for. Some surmise that if welded that the towers would likely still have collapsed but may have stood longer allowing more to escape.

Now, with the outer shell pulling on the floor joists, the core columns compromised redistributing the load on the other core columns and producing a bending moment and the fires heating the columns to plasticity, it was not IF the towers would collapse, but WHEN.

Yes the building method was innovative for it's time but there was nothing wrong with the design of the towers. Even with the insulation stripped off they lasted something like 90 minutes so without any ability to fight the fire and that is a testament to how well they were actually built.

 

The OP: This is proof positive of why truthers are dismissed out of hand. The math is wrong, the premise flawed, and the logic faulty. First when the plane pnetrated to the central core you created the equivalent of a forced air feed for the fire.

2nd your estimate of the avaialble fuel is extraordinarily low and fails badly to take into account the wide spread use of magnesium among other elements currently in use in office furniture.

3rd your statement regarding various plastics and what have you that are very common in office buildings is also grossly inaccurate. There are between 8 and ten different varieties of plasic likely to be found in Office buildings all have quite different ignition points and heat generation capacities. Within thirty seconds of the impact there were thousands of different things burning all generating different amounts of heat. Add to that an extra 165 tons of aircraft, and the draft from the ruptured central a\core and you have a classic set up more than capable of producing the heat necessary to weaken steel by the 30 or 40 percent necessary to cause a structural collapse. Had not the Central core been penetrated there is a chance that the building might have survived.

 

Anyone care to guess how many batteries the servers had as backup?

Anyone care to guess what those chemicals do in a fire?

 

I stopped reading your post immediately after you said steel is an ideal heatsink. That's a lie and you know it.

 

At a guess I suspect most truthers have never been in a building more than three stories tall, are completely unfamiliar with elevators and how they are built and designed and have at most a BA in literature.

 

they know little about anything, they just latch onto BS and pile it up and up. If you debunk them, they throw MORE BS at you and keep you debunking. If you somehow keep up with them (hard to do as they are relentless in their pursue of cuckoo theories) and debunk all of their BS, then they just tell you that you are just in denial and run away.

their stupid conspiracy theories have been debunked time and time again and they have nothing more than cuckoo theories.

 

I know but it is fun watching there butts disappear in a cloud of dust. I don't do it for them anyway I do for those who don't know any better that might otherwise take this crap seriously.

 

yeah, that's what's unfortunate, their BS sells... just like WWF and gossip magazines do

Their strategy is to flood the internet with BS, knowing that they are not going to be taken seriously and so their BS will overwhelm the actual truths which are readily available on the internet.

'Bush wanted to bring down the symbol of the US financial might and power, kill 3000 americans to make the government more powerful and open the door for more control of it's people and other countries'

I mean...

 

And of course he must have had Obama in mind when he was doing it. LOL

 

So it would require every last bit of steel in the towers to melt in order for them to come down? Who'da thunk it? I never would have guessed that something so preposterous and counter to common (*)(*)(*)(*)ing sense would be a reality...

 

Why would anybody elaborately make it look like jetliners crashed into buildings? It would be much easier to create the appearance of the attack by ACTUALLY crashing the jet liners into the buildings.

Also if you wanted to blame it on Muslim extremists, why bother to paint yourself up and dress as a Muslim and plant the evidence, when you can just hire the 10 Arabs to do it for you.

Too many people will independently investigate within your government and they will report back to you who they think are guilty, and about who they think are the best countries to attack for the horrible crime. Next, your country will attack those countries, and your nefarious objective is complete.

However, the people will investigate to prove you had this goal. They will not believe that Muslims could have hated you enough to do it themselves without encouragement.

It is a brilliant plot when you hire the middle easterners to do it. Nobody will disagree.

 

We can safely deduce that the OP never has darkened the door of an engineering school. He'd never survive the third year - where real engineers learn this stuff.

The OP, like most truthers, ignores the major fuel source: tens of thousands of tons of paper, stirred up by the impacts and blowtorched into ignition by the burning jet fuel. Add in the fact that breaches in the sides and floors made a wonderful chimney - drawing in fresh air and blowing out the smoke.

An engineering student finds out that the fuel is irrelevant. If you maintain the right combustion conditions you can get high temperatures.

The metal getting hot enough to mechanically fail is just a matter of heat balance. Too much heat in and not enough out and the temperature rises. This is why boilers don't melt down despite containing fierce fires. A common coal stoker easily makes a 2500 degree fire but doesn't melt. Why? Because the water in the tubes takes away the heat to make steam. A boiler man fears scale buildup on his tubes because that insulates the water side of the tube and allows hot spots that blow out.

Stripped (by the impact) of their refractory protection, the beams of the building were essentially dry boiler tubes (another boiler operator nightmare). The fire put heat in but it had nowhere to go and so the temperature just built up. At 1400 degrees F, the chrystal sturcture of the steel changed and put the beams under mechanical stress.

Over 1200 degrees F they Young's modulus of the steel attenuates and at some point hot brittle fracture is inevitable. The hottest spots of all would be the column-to-beam joints. The joints - weakened by the fire and pulled by the shortening beams and still bearing the weight of the building about it, fails. Because of the relatively square plan of the WTC, all four corned let go more or less at the same time.

After the first floor fails it (and all the building above it fall exactly one story to the next floor which up til now had not failed. Ever see a shear press? Big cutting edges force their way through metal driven by enormous flywheels. A 8,000 ton shear slices a 14" wide-flange section easily. The weight of the building above the falls fifteen feet, picking up enormous kinetic energy. If the joints of the next floor can absorb that energy, they stop the collapse. but the enrgy was too great and it blows through the structure of the next floor sown and never stops. On each successive floor it gains speed and becomes so great even structure undamaged by the fire cannot withstand the enormous shear energy. By time it drops more than ten floors, the collapsing wreckage for all practical purposes doesn't slow down at each successive floor at all and the wreckage is moving downward at a very respectable clip when it hits the foundation.

But the don't teach this stuff in victim groups' studies classes.

 

All these geniuses believing bearded cave dwellers took out the US military on 9/11 are a trip. So technical...so...."educated"...yet they believe Walmart box cutters and magic pilots turned the US upside down. Smart folks...no doubt.

 

None of the hijackers dwelled in caves. Most were college educated and several had pilot's licenses. Box cutters were not the only weapons used: flight attendants reported seeing bombs strapped to them.

Your bigotry and racism are showing. Now be a good lemming and hand wave this away with an insult.

 

You're doing a fine, fine job for the evil people. Congratulations. No insult there boss.