Design patterns are commonly used in object-oriented modelling for the solution of frequently appearing design problems. Until recently their use was restricted to the domain of software engineering, However, object-oriented modelling is an important topic of the new mandatory subject informatics, which will be introduced during 2003 in all the four hundred Gymnasiums of Bavaria. In this paper we want to show that design pattern might add a valuable contribution to such a mandatory subject, which has its main focus on teaching the substantial concepts of informatics and on stimulating mental models to give real understanding of informatics.