The need for artistic expression in children appears in early childhood. Although the first art pieces of their children seem to make no sense at all to the parents, they are a vital form of the children's communication with the adults. A child's artwork can tell us a lot about his or her personality, emotions, wishes and fears. In addition to this, it can help us find out what is the level of their intellectual, motor proficiency, social and emotional development. In order for us to be able to determine some of these things, it is necessary to be familiar with the development of children's artistic activity. The development process proceeds through four different stages, each of the stages having its own characteristics and regularities which determine it. During the first stage, the child cannot tell a lead pencil from a colored one, but uses colour to paint a line, not to paint a surface. During the second stage, the child is already capable of expressing himself or herself in a more complex manner using colour provided that he or she is encouraged to do so through a variety of visual art forms. During the third stage, the child does not use colour anymore only to paint a line, but paints a surface as well. At this stage, we can observe the child's emotions based on the colour he or she uses, unlike the previous stages at which colour did not reflect the child's mood or emotions. In addition to being familiar with the development of his or her artistic activity, it is extremely important to communicate with children about their art work. The practical part of the paper contains the preparation for a visual arts activity, a brief review of the activity and the children's art works. The activity entitled 'The Transformation of Music into a Visual Experience' was performed in such a way that the children, after listening to a musical work, used colour to create their artistic expression. The performed activity shows us the actual difference between the children's minds and the way in which each individual thinks and acts.