Have students provide examples of materials that fit each description: Elastic ... deformed rock outcrops on the Earth's surface. Ask them explain what kind of deformation they observe in each ...

Push an object's ends together, eg when an empty drinks can is squashed. A rubber band undergoes elastic deformation when stretched a little. A metal drinks can undergoes inelastic deformation ...

Materials like clay or putty usually show non-linear extension. Linear extension and elastic deformation can be seen below the elastic limit.