You can go further with this idea of purpose and audience. Children don't know much about essays but they are surrounded by text formats which they absolutely understand. I used to have them prepare radio news bulletins in groups.
The point of this work within English is that pupils understand the particular language of radio news.
News has specific vocabulary that you would never use in real life. And the bulletins has a complex text-level structure, with levels of headline, hierarchical sequencing and clear closure.
To discover all this, I used to start this work by playing recordings of news programme and analysing them with pupils. This is called text type analysis. Having done the analysis, they would create their own programmes, using what they'd learned.