In this course, we will look at how internal and external factors determine a material’s reaction. The inner structure of the materials, starting from the atomic/molecular structure of materials, to their micro-structure relates to their mechanical properties. We will also investigate how this microscopic structure will influence the macroscopic behaviour of these materials: how do they react to a force applied, a momentum present? But there are external factors as well: how much influence does the shape of a part have or the way we mount it? Stress and Strain in a component are a good example, as they always depend on the material properties, but also on the cross-section and the shape. And we will look how non-technical factors will influence our choice of material, how a part can be designed for lowest cost, lowest weight or lowest environmental impact.