One morning, I handed a small group of toddlers a white crayon each. We talked about the color of the crayon and the color of the paper in front of us. When the kiddos eagerly got to drawing, they stopped abruptly with confusion on their faces.
"Mine is broken!"
"It doesn't work!"
"I need a new one!"
I explained that their crayons did indeed work and that they were drawing invisible pictures that would show up once we added watercolor to the mix. When presented with the idea of water color, you can bet the crayons were immediately abandoned as the kiddos clamored for paint. After a little coaxing, and demonstrating how they could feel the wax on their paper, one of the three-year-olds told me she could see the crayon. That's all it took as the rest of the small group got to squinting at their papers.
Much scribbling was done and then liquid watercolors were passed out.
I love the magic of children when they paint.