Thermochromic materials are substances that change color in response to temperature variations. These materials can be found in various forms, such as inks, dyes, and plastics, and are often used in products like temperature-sensitive mugs and clothing. When the temperature rises or falls, the molecular structure of thermochromic materials alters, leading to a visible color change. This property makes them useful for applications in safety indicators, mood rings, and even smart packaging, where temperature monitoring is essential.