I used 12x18 black paper and gave the kids each a sheet of 12x18 newsprint. They drew the LARGEST oval they could on their newsprint and cut it out. This was used as the masking area as the students drew the "rays" and smudged them radiating from the snowglobe.
I forgot to mention we used white oil pastel. My first group I used white chalk and we had fingerprints. Everywhere. Yuck. The kids drew simple evergreens in the globe and topped the whole baby off with some glue dots for glitter. This was the "snow" in their globe. Glitter does make the world go 'round, ya know...
They're lovely, and the kids love them. Glitter and all!