Which term describes the ability to permanently change in shape?

Which term describes the ability to permanently change in shape?

• A. Elasticity
• B. Plasticity
• C. Ductility
• D. Malleability

Answer: (B)

Think about how materials deform when a force is applied. If the material returns to its original shape after you remove the force, the deformation was elastic. If it stays deformed and does not go back to its original shape, the deformation is permanent. The term for that permanent change in shape is plasticity. Ductility and malleability describe other aspects of how a material can deform (being drawn into wire, or hammered into sheets), but they don’t specifically define permanent shape change like plasticity does. Elasticity is the opposite idea—reversible deformation. So the term that describes the ability to permanently change in shape is plasticity.

Think about how materials deform when a force is applied. If the material returns to its original shape after you remove the force, the deformation was elastic. If it stays deformed and does not go back to its original shape, the deformation is permanent. The term for that permanent change in shape is plasticity. Ductility and malleability describe other aspects of how a material can deform (being drawn into wire, or hammered into sheets), but they don’t specifically define permanent shape change like plasticity does. Elasticity is the opposite idea—reversible deformation. So the term that describes the ability to permanently change in shape is plasticity.