Model is made up of hinges. The truss's under-load qualitative behaviour can be seen in the model. Compression members can quickly buckle, or curve, because they are very flexible. However, the tension member continues to be tight and straight. The learner will thus be able to visualise the many types of stresses, such as compressive or tensile stresses, that a truss member would experience under varied loads. The learner will be able to see how the angle between members at each joint changes slightly in the case of pinned joint truss..