In this physical activity, two lines of learners link hands and arms to model a beam subject to various loading schemes. They discover how inter-atomic forces react to the five fundamental load types that can act on structures: tension, compression, shear, bending, and torsion. This activity can be used as an introduction to these forces or as review. Note: The description refers to learners as "molecules of steel" and their arms being the bonds between them. Since steel is an alloy of multiple elements, each learner would represent an atom and their arms are the inter-atomic forces which join them.