Smart materials are special types of materials that can change their properties in response to external stimuli, such as temperature, light, or pressure. For example, shape-memory alloys can return to their original shape after being deformed when heated. These materials are used in various applications, including medical devices, aerospace, and automotive industries, making them incredibly versatile. Another fascinating aspect of smart materials is their ability to sense and respond to their environment. Piezoelectric materials generate electricity when subjected to mechanical stress, which can be used in sensors and actuators. This responsiveness allows for innovations in fields like robotics and wearable technology, enhancing functionality and efficiency.