To try this out with your kids, you'll need black paper, glue, salt, food coloring, and a medicine dropper.
The colors need to be a lot darker than you would expect. The salt will absorb a lot. Ours actually dried a lot lighter than I was expecting.
Use the glue to make fireworks designs. I helped one of the boys with these and let the other kids design their own.
Sprinkle the designs with salt and shake off the excess salt.
Let the kids use the medicine droppers to drop colored water onto their designs.