Sir HC,
The reason my vacuum is caused, is by the burning of the air by the engines and by the pilots lungs, (albeit minutely compared to the engines consumption).
Nothing to do with the complicated dynamic properties associated with a jet engine, but simply the conversion of fossil fuels to carbon dioxide.
Much the same as the old candle in an up turned jam jar.
As the flame burns the air, the candle gradually goes out, as there is no further air to burn.
The smoke produced follows the draught created by the carbon dioxide falling to the lowest point.
Should the jar be sat upon a dish with water in, the effects of the vacuum can be seen by the rise in water level within the jar.
OK, so in reality the engines will flame out and the pilot will die before any reasonable vacuum is produced, but the conversion of the air to a heavier than air gas will cause the scales to show, if sensitive enough, an increase in the weight of the total contents of the box.
edited to avoid the use of atomic weights
Last edited by SilsoeSid; 6th Dec 2004 at 00:09.