Temperature-sensitive inks are special types of inks that change color or become invisible when exposed to different temperatures. These inks are often used in products like thermometers, packaging, and security labels to indicate temperature changes or to provide visual effects. These inks work by incorporating materials that react to heat, such as thermochromic or photochromic compounds. When the temperature rises or falls, the chemical structure of these compounds alters, leading to a visible change. This property makes temperature-sensitive inks useful in various applications, including food safety and temperature monitoring.