Emer,
thanks for sharing your recommendatins of https://www.bytello.com/home
and Chatterpix. I have just downloaded Chatterpix and it is simple and fun. Would you have talking shadows?
I agree that with infants, ‘shadows and how they are made’ would be sufficient. The children could revisit this when they are older to connect to the seasonal and daily changes in the Sun’s position and how that affects the length of the shadows.