This project was simply to help my children visualize a bit of how massive one galaxy is, as we were learning about the universe and its scale.
Start by looking at photos of galaxies. Give each child a regular-sized piece of plain paper. Have them draw a spiral using either school glue or a glue stick. Very quickly sprinkle it with glitter and tip back and forth to cover. The photo below shows what happens when there's a bunch of glue in the center.... it runs. (Hey, a little more running on the upper side and it'd be a great barred galaxy!)
Each tiny piece of glitter represents one star. Look at your 'galaxy' closely for a while, then watch this video.
I used some gorgeous ultra-small glitter left from another project- so we did this outside. On the patio, 20 feet from the house. It wasn't far away enough. Next time we'll do this over grass, so the glitter is less likely to get tracked back indoors!
After they've dried completely, put them in a plastic page protector to keep the glitter contained. And marvel at what we're a part of.