Bone vs steel

Bone is not “five times stronger than steel” without specifying what is being compared. Its strength depends on loading direction and type, while steel properties depend on the alloy. For example, a biomaterials review reports cortical bone compressive strength of about 103–140 MPa, while structural steels are generally higher. Bone can be efficient in strength relative to its mass, but a universal “five times” claim is misleading. The illustration is an AI-generated synthetic diagram.