I am wondering what the chemical validity is of jet fuel actually melting the steel beams that held up the twin towers during the September attacks.
Jet Fuel type A (Jet A) burns at approximately 2,230 °C. 0.2% carbon steel has a maximum forging temperature (i.e., the point at which it'll melt) at about 2410 °C, while 1.5% carbon steel is at about 1920 °C. This also doesn't take into account effects that happen with how aerosolized jet fuel will burn, which is, much hotter, and strange effects that'll happen as everything else has it's surface area very spontaneously increased, subjected to a large amount of kinetic energy at once, and then lit on fire.
Not to mention everything else burning at the same time. Finely shredded aluminum is very flammable.
Also: As a final note: The steel didn't actually have to melt, persay. It only had to weaken enough that the mechanical forces of the skyscraper that it was supporting became too great for the softened steel, at which point it'll all collapse in a chain reaction.
TL;DR: Conspiracy theories are BS.