Last time we studied space, we explored shadows indoors and outdoors using flashlights and other objects. I had books from the library with photos of the moon and space objects. While we were looking at the books, one child asked some great questions and I ended up doing a simple model of how the moon revolves around the Earth and the earth revolves around the sun. A few others got interested, too, and were able to talk about it later. Many children in the class also understood the concept of the sun hiding behind the clouds due to a failed Smores experiment (we tried to make Smores outside on a cloudy day).