We are doing an Astronomy unit this month, and we began by discussing the universe. For a hands-on example, Miss M made a mini-universe in a jar.
First, she added glitter (she chose blue, green and silver) and stars I punched out of aluminum foil into a baby food jar.
Next she added a dropper of vegetable oil.
Finally she poured in water to fill the jar 3/4 full, and I helped her screw the lid on tight.
When she shakes the jar it looks similar to the pictures of the universe we saw on the NASA Web site.