Interesting reply Luftwaffle, always great to see a different point of view from one's own.
I agree that the way you've explained the question is a far simpler and more commonly understandable way of explaining it, my only 2 comments are:
(1)
<font face="Verdana, Arial, Helvetica" size="2">Remind the student that lift increases with speed and angle of attack, and that drag increases with speed and with the area presented to the air.</font>
My comment here is that drag is also dependant on AoA (Induced drag), so I would think that this needs to be emphasised too, not just the aircraft's attitude (area).
(2)
<font face="Verdana, Arial, Helvetica" size="2">. Does the angle that provides the best compromise between lift and drag depend on how much the airplane weighs, or just the outside shape? Once you get them to agree that there is one best angle, then just draw the airplane, the angle of descent and the eventual landing spot.......
If the aircraft is heavy, it will need to go faster, and if it is lighter it will go slower, but either way it will follow the same glide path to the same spot. </font>
My own question following this response would be "if we are going faster, then we are producing more parasite drag, so why does our angle remain constant?".
We both know the answer, of course, but I would be interested to see how you could phrase the answer, as I am unsure of how to express it without resorting to vector theory again
Interesting discussion as always,
Cheers,
Grade 3