The first lesson saw Year 6 explore these methods and others to see which effect they preferred and it also gave them an opportunity to master the technique. The following 1-2 lessons were spent creating their artwork that was based on this and this. I loved both of these pictures and the class was tasked with creating their own polar landscape also featuring the northern lights. Their final job was to add a few words or lines from their arctic poem that they'd created in literacy.
Here are a few examples of their work, I think they've come out beautifully:
(This person actually used the water/paint/clingfilm for the Northern lights!)