This is not an original metaphor.  I don’t remember where or when I first heard it nor do I know who first came up with it, but it has become a favorite.  I introduced it through the first week of school and come back to it again and again through the year.

It is a metaphor of an iceberg.  The iceberg we see is huge, majestic and foreboding, all at the same time.  That iceberg that we see, is only 12 % of the iceberg that is there.  The other 88% is resting silently and hidden under the water.  (The science behind it is explained well here.  http://www.bsharp.org/physics/icebergs)

This image of an iceberg becomes a metaphor when you think of it as an idea, a thought or an argument.  The portion above the surface is the obvious part, but the majority is hidden, the depth of it is not obviously visible.  When a student offers me an abviose answer I often just ask, what’s below the surface? or, think deeper.  It becomes our own little key word to trigger a habit of looking beyond the obvious for the underlying assumptions.  It has obvious implications for TOK but I use it in grade 5 and grade 2.