In case you were as skeptical as @moorethanhappy and I that this would actually work, here’s proof. 
Just drop a dab of food coloring in an ice 
tray overnight and when you wake up in the morning 
, you’ll have a water color 
sensory experience ready to go. We used the letter C worksheet 
provided by @experiencecurriculum , but really you could have used anything, including blank paper, white coffee…