Recently during my discussions with people about 9/11 I have noticed that discussing the tops of the towers is usually much more effective than other smoking guns, even building 7. I have tried to no avail to simplify the language used to describe the various laws of physics broken by the pulverized concrete, the expanding dust clouds, the lateral ejection of the steel beams, the speed of the collapse, the burning temperature of jet fuel, the heat-sink properties and melting point of steel, but invariably the non-scientifically minded always have doubts (gravity could cause the dust and lateral ejection, fires and debris downed building 7, the jet fuel mixed with other materials in the buildings, etc.)

However, one argument usually stumps them and forces them to admit that it there are unanswered questions. Namely, the disappearance of the tops of the towers. The argument they usually present me is that the tops of the towers crushed the bottoms of the towers. So I ask them, if that is the case, where are the tops of the towers. There should have been two roughly 30 storey tops of the towers sitting at ground zero, but they were pulverized as well. They usually blurt out "well the bottoms crushed the tops" which I instantly jump on, saying that if the tops crushed the floors below, how could the floors below have crushed the tops? This usually shuts them up because no scientific knowledge is necessary. It is just common sense that the tops of the towers should have been left sitting at ground zero if they were the cause of the gravity collapse, and yet they were exploded as well. How can this be without the use of explosives. Just another point to think about the next time you are debating a skeptic.