Deformation refers to the change in shape or size of an object due to applied forces or environmental conditions. This process can occur in various materials, including metals, plastics, and rocks. Deformation can be elastic, where the material returns to its original shape after the force is removed, or plastic, where the change is permanent. In geology, deformation is significant in understanding how the Earth's crust changes over time. It can lead to the formation of features such as mountains and faults, which are related to tectonic activities involving tectonic plates. Understanding deformation helps scientists predict natural events like earthquakes.