Grab the white paper, a brush, pour into a saucer of milk. Ask your child to draw something, instead of using paints milk. When it dries, the picture will disappear.
How now to see what is drawn on a sheet of paper? To do this, simply ironed the paper iron or hold it over a lamp. Now you can organize the exchange of classified images with other family members. Received a secret message is always interesting to see what hides a blank sheet of paper.