Spray bottles
Corn starch
Baking soda
Food coloring or washable watercolors
(For more vibrant colors, use tempera paint rather than food coloring.)
Directions
Fill the spray bottles 1/3 of the way with a baking soda and corn starch mixture, using roughly equal amounts of both ingredients. Add a few drops of food coloring or washable watercolors, and then fill the bottles with very warm water, leaving a little space at the top of the bottle. Use a butter knife or similar to stir the mixture as best you can, and then place the spray spouts on and shake the bottles really, really well. You will want to shake the bottles once more just before play, as some of the corn starch does settle at the bottom of the bottles.
Invite your child to use the spray chalk to paint large murals or spray directly onto the sidewalk. Your child will love making colorful creations with the spray chalk.