The paper reports on University seminars of mathematical modelling at school, that were held together by the departments of mathematics and mathematics education and some schools in Hamburg. Prospective teachers together with students in upper secondary level carried out modelling examples either in ordinary lessons or special afternoon groups. They tackled authentic problems proposed by applied mathematicians working in industry. In this paper we consider three of these examples in more detail and describe students' attempts at solving the problem. After a description of the theoretical framework of modelling in schools and the framework and the structure of the course diverse modelling attempts by students to solve two modelling examples are presented. Finally an evaluation of the series of semmars is presented.