This set of resources from the IOP takes a little while to get your head around but repays the effort handsomely. Teachers new to the profession, teaching outside their specialism or simply wanting to refresh their practise will find much food for thought here. The emphasis is on building a really good understanding of wave behaviour and developing precision in thought and language.
Teaching and Learning Issues 10, “Light spreading Out" links with Physics Narrative 6, “Intensity May Vary on the Journey”. Together they provide a great base for teaching the inverse square law.