Make colored sand art by stirring a chalk stick in a bowl of salt. it changes the color. Stir less for light color and more for dark richer color. (I used to do this with salt and food coloring. but the chalk stick idea is brilliant!
this one sounds even easier to make: bubble snakes = easy quick craft. Cut the bottom off water bottle. Put old sock over bottom and duct tape. Add food coloring for fun. Dip end in dish soap mixed with a little water