We used liquid watercolors, medical droppers and thick watercolor paper. It turned out that filling a dropper with paint was harder for my child than I thought it would be. Even though she did not fully grasp the whole process, it was definitely interesting to her. In the beginning, I was filling the dropper with paint myself and she was squeezing it on a piece of paper. Towards the end of our painting session she was able to fill it with just a little bit of paint.