I've seen the same old explanatory chestnuts a thousand times - "the water cycle" being the most common (daft really, because the water cycle is best explained diagrammatically). Another standby is "how to make a mummy"...
the Egyptian kind, I mean.
I was discussing this with some teachers. We began talking about how "real life" explanations are often quite short, hinging on causal connectives such as "because", "so" or "as a result". We decided that a simple way into this would be through role-playing explanations before writing. We listed interesting ideas: Why are bananas curly? Why don't rainbows wobble in the wind? Why did you break into the three bears' cottage? Why do sloths hang about? Why do cats purr? The only rule was that the children had to use a causal connective.
Tim, one pupil, wrote: "Long ago, in Egypt, cats gathered at the pyramids for a sound competition. They invented the whistle, the high-pitched screech and the questioning meow. Then one cat wobbled his lips and made a low growling sound. It sounded so peaceful that everyone joined in.
Unfortunately, the wind changed direction. As a result, all the cats were stuck with the same low purr."
Pie Corbett is a literacy consultant