Color-changing materials are substances that can alter their color in response to external stimuli, such as temperature, light, or pH levels. These materials are often used in various applications, including textiles, coatings, and sensors. For example, some thermochromic materials change color when exposed to heat, while photochromic materials react to changes in light intensity. The science behind color-changing materials involves the manipulation of molecular structures that respond to environmental changes. When these materials are subjected to specific conditions, their molecular arrangement shifts, leading to a visible change in color. This property makes them useful in innovative designs and practical applications, such as smart clothing and temperature indicators.