Testing the ‘spider silk can stop a Boeing 747’ claim: An integrative mechanics-of-materials teaching case

This paper develops a ready-to-use mechanics-of-materials teaching case in which students test the popular claim that a pencil-thick spider-silk strand could stop a Boeing 747. The case integrates engineering stress–strain behavior, work–energy, axial capacity, self-weight and engineering judgment within two staged exercises. Students first convert the area under an engineering stress–strain curve into tensile work per unit initial volume and derive an energy-based lower bound on strand length. They then derive a self-weight upper bound and determine whether the two bounds overlap. For a representative landing envelope and a 7-mm equivalent solid strand, the baseline calculation gives an energy requirement of 157 km and a favorable vertical-support limit of 173 km; at a 60 ∘ support-tangent angle, the common interval disappears. The supplied worksheet, instructor guide, marking criteria and transfer task make the case directly assignable. The intended learning outcome is interpretive as well as computational: students determine what compatibility of two necessary mechanical conditions establishes and identify the additional physics required for an actual arrest. The contribution establishes the mechanics and assessment structure of the module, providing a defined basis for subsequent classroom evaluation.