I am repeatedly told by skeptics that the molten metal seen at the South Tower was aluminum from the crashed plane. Typically, they will reference Professor Judy Wood's attempt to "prove" this point. I think it's about time we dispelled the myth.
Firstly, Professor Steven Jones conducted some experiments and came to the conclusion that it could not be aluminum because aluminum at that temperature in daylight would appear silvery or a faint yellow, not bright yellow.
Aluminum is an excellent reflector of light, which is why it is used on mirrors. However, good reflectors are also low emitters of light. Furthermore, the high reflectivity of aluminum causes it to reflect a lot of the ambient light. In a dark room, there is no ambient light, so your eyes would see only the glow from the aluminum. However, if there is any ambient light, some of it will be reflected by the aluminum.
What this means is that when you look at molten aluminum, your eyes will see the glow from the aluminum mixed with the reflected ambient light. If the ambient light is at a high level, your eyes will see more reflected ambient light, which makes the aluminum appear silvery.
Every object at 1000°F produces red light; every object at 2000°F produces orange light; and every object at 2700°F produces white light. However, different materials emit different amounts of light, and different materials reflect different amounts of ambient light. Aluminum does not emit as much light as iron, and it reflects more ambient light. The end result is that the iron will have a brighter glow.
In order to fully understand this concept, a piece of aluminum and a piece of iron would have to be placed side by side and then heated up to the exact same temperature. We would then clearly see that the iron glows brighter than the aluminum, even though they are at exactly the same temperature.
In the photograph below the molten aluminum inside the crucible is glowing a faint red, but the aluminum at the edge of the crucible is reflecting a lot of sunlight, so it appears silvery.
This photograph was taken inside a building, so the ambient light is at a lower intensity. This makes the crucible appear a brighter red, but the aluminum at the edge of the crucible (where the light is brighter) is still silvery.
If the lights in this building were turned off, all of the aluminum would glow a bright red.
Professor Jones concludes the yellow liquid in the South Tower was molten iron. Since an ordinary office fire cannot melt iron, this implies that something such as thermite was inside the tower.
Thermite is still used today for repairing railroad tracks because it is a simple way of producing molten iron. Here are photos of people using thermite to repair railroad tracks in Australia:
However, in February 2006, Professor Judy Wood and her student Michael Zebuhr conducted an experiment to determine if Professor Steven Jones was correct that molten aluminum would appear silvery at high temperatures. The results of their experiment can be found at the site of Professor Wood:
The purpose of their experiment was to prove that molten aluminum does indeed glow when melted, and that Professor Jones is incorrect when he says molten aluminum appears silvery.
However, take a close look at their photographs. Notice that the ambient light is at a very low level. In dim light, every object at 500°C (932°F) will appear red, and every object at 1100°C (2012°F) will appear orange.
In a completely dark room, an object as low as 400°C will appear dark red.
Therefore, this is a deceptive experiment. In order to be an honest experiment, they should have put aluminum and iron next to each other. That would allow us to compare the two metals when they are at the exact same temperature.
Furthermore, they should have conducted the experiment in bright ambient light in order to duplicate the conditions of the molten metal that poured out of the South Tower.
Here is a video of the stream of molten metal (believed to be iron) which poured out of the building:
Does this look like molten aluminum to you? Or, is this reaction more consistent with the use of thermite as seen in the following experiments...