As far as maxims in the English classroom go, ‘show don’t tell’ is right up there with ‘don’t use the word nice’ and ‘no, the writer doesn’t do that to make you want to read on’. The reason these become maxims, though, is because it’s really quite difficult to explain why , for example, we should avoid saying a particular image makes us want to read on or that we should aim to show the reader an emotion and not simply tell them about it. We can explain these things, model the alternatives, but still students don’t always intuitively understand why, and so, out of habit, they often revert back.
Encountering exactly this scenario with the idea of ‘show don’t tell’, I set about thinking of a way to make this maxim as concrete and meaningful as possible, and what I came up with, after a few iterations, was the below iceberg task.

The aim is a simple one: can students find a way to convey and capture the specified emotion without telling the reader that is how their character feels. What might, for example, reveal the person thinks the food tastes disgusting without actually saying this? Perhaps, they slowly drag their fork towards their mouth as they grimace or maybe their teeth, clenched shut, barricade themselves against the incoming sprout attack.
The image of the iceberg neatly captures what TS Eliot described as an objective correlative: an object within the textual world that embodies or correlates to the emotion or feeling of a given character. In fact, the iceberg itself functions as a kind of objective correlative all of its own, as it comes to represent the visible, in this case the object, conveying the invisible, the emotional disposition of the character which lies beneath the surface of the story.
Having used this strategy a few times now with different classes, it does genuinely seem to work at getting students to better appreciate and grasp what we mean by ‘show don’t tell’. Don’t tell me the food is disgusting, show me. What should be visible to me in the story is the tip of the iceberg and not what lies hidden beneath.
So taken was I by this general principe of using the iceberg to represent the idea of ‘show don’t tell’ I repurposed it in my literature teaching, as below.

The idea is exactly the same, but now students need to recall quotations that might show or capture a key idea about a character or the text. Not only is this a really valuable opportunity for recall, but it also reinforces the substantive ideas of the text and offers an exemplar of ‘show don’t tell’ that could then help to refine their own writing.