What term describes materials that change in properties in response to stimuli?

• A. Smart materials
• B. Thermochromic Materials
• C. Shape memory plastics
• D. Nanotechnology

Answer: (A)

Materials that change their properties in response to external stimuli are known as smart materials. This category covers substances that adjust shape, stiffness, color, damping, or other characteristics when triggered by things like temperature changes, electric or magnetic fields, light, or mechanical stress. For example, shape memory plastics belong to this group because they can change shape with heat; thermochromic materials change color with temperature. Nanotechnology, while broad and important, isn’t specifically about materials that respond to stimuli, so it doesn’t capture the defining idea as directly. Smart materials therefore best describes the concept of materials that actively adapt when something in the environment changes.