Richard Gage, from Architects and Engineers for 9/11 Truth, and Dave Thomas a physicist from New Mexicans for Science and Reason, joined Ian Punnett for the entire program to debate how the World Trade Center buildings collapsed on September 11, 2001.

Gage believes the WTC towers were brought down by controlled demolition involving thermite. "I think the dust of the World Trade Center reveals the secret of the cause that we're all looking for," he said. The dust contained billions of tiny spheres (about the diameter of a human hair) of previously molten iron, Gage revealed. This means the iron in the spheres sustained temperatures exceeding 2800 degrees, twice as high as what a jet fuel fire can produce, but within the range of a thermite reaction, he noted. In addition, Gage said the dust contained hundreds of small red-gray chips, which he identified as highly-advanced nano-thermite composite explosive material.

Thomas expressed his support for the gravitational collapse model. As the planes slammed into the twin towers, they cut through steel support structures and ignited immense fires across the floors of the building, he said. Heat from the fires further weakened the floor trusses, causing them to sag and pull in the perimeter walls, he continued. The additional weight, along with reduced support, sent the first section crashing down onto the floor beneath it with a force 30 times that of its static weight, Thomas explained. "The collapse was considered inevitable because every floor had even more dynamic force going at it," he added.

Responding to Gage's dust claims, Thomas pointed out that scientific analysis uncovered nothing unusual about the iron microspheres, and any ingredients taken to be thermite could just as easily be from the building's ordinary components (iron beams, paint, aluminum siding, etc). The two men argued about whether or not pools of molten steel had been found at the WTC site, if explosions and flashes of light were heard and seen that day, and what happened to all of the pancaked floors. They also shared their theories about what brought down Building 7 (the one not hit by a plane). Gage said it was a implosion produced by thermite; Thomas blamed damage caused by the north tower collapse, huge fires within, and a design flaw.

Physicist Kim Johnson and chemist Niels Harrit joined the discussion in hour three. Johnson observed that the WTC skyscrapers began falling precisely where they had been struck by the planes and the fires broke out, evidence he believes favors the gravitational collapse model. "A steel-framed high riser does not collapse due to fire," Harrit responded, citing an experiment by British Steel that showed an 8-story steel structure could repeatedly withstand attempts to burn it down. Harrit, like Gage, thinks the three buildings were brought down by controlled thermite explosions. Johnson called attention to the fact that none of the hundreds of dogs used to locate survivors, many of them cross-trained to find explosives, detected any trace of thermite at the 9/11 disaster site.