TURIN....
"Most people find mathematics a very useful common language in these circumstances. It introduces a discipline that avoids the sort of confusion etc etc. "
I have to disagree. Most people use the spoken word to explain anything. Mathematics confuses almost everybody at one level or another. See above.
I have to completely disagree with your stance. Not to be personal but your attitude contributes to the lack of scientific literacy throughout North America and many other places. I can't stand people who justify using ambiguous and/or incorrect terminology or explanations, because in reality they don't understand the topic themselves. Frankly, if you don't understand it, you shouldn't be the one telling everyone how it should be described! You should look into Richard Feynman - he was a physicist who is known for his excellent explanations yet he also shares the same point of view as I do on this matter. If you don't want to listen to me, at least listen to a man who definitely had a good idea of what he was talking about. [/rant]
To add onto what John Tulla posted, for those of you who still don't quite understand/believe that a tail almost always will produce downlift, look at this video at 0:40.