I spied this fun idea on Pinterest the other day and immediately had to try it out! It turned out to be a very easy, frugal, and fun activity that entertained my 8 and 6 year olds for about an hour.
Line a baking sheet with a layer of baking soda. Add food coloring to cups of vinegar. Let the children use the droppers to make pictures in the baking soda with the colored vinegar.
So much fun! Easy cleanup too!