DIY Drawing and tracing using shadows: great craft/art for kids too. "Nature and shadow- what if we take out the paints and paint in the lines…."… great idea for tracing. Take a quick pic then don't have to worry about sun changing places.
Put real spiderwebs on paper. preserve a spiderweb on paper to explore/look at. or put the black paper behind it so it can be seen in detail and then take a picture so you don't have to destroy the spider's web.