This Activity is meant for Cub Scouts.
Decide for yourself if it is appropriate for your younger scouts or not.

White posterboard, white glue, colored sand, bowls, spoons, small paint brush

Sand is easily vacuumed up.

Draw a design on poster board.
Paint a thin layer of glue on the portion to receive sand.
Use spoon to sprinkle sand onto board.
Shake off excess sand.
Repeat for each color, working from dark to light sand.