Explore the fundamental concepts of biomechanics and orthopedics in this 45-minute lecture from Yale University's Frontiers of Biomedical Engineering course. Delve into the material properties of elasticity and viscosity as Professor Saltzman guides you through experimental setups for measuring these properties. Learn about stress-strain relationships, Young's modulus, and shear stress in fluids. Discover how springs and dashpots are used to model ideal elastic and viscoelastic materials, respectively. Gain insights into how biomaterials combine these properties and can be described using physical models. The lecture covers introduction, elasticity experiments, viscosity, deformation and viscoelasticity, and concludes with a summary of key concepts.