Kinetic theory is a scientific explanation that describes how matter is made up of tiny particles, such as atoms and molecules. According to this theory, these particles are in constant motion, and their movement is influenced by temperature. Higher temperatures mean faster-moving particles, while lower temperatures result in slower movement. This theory helps to explain the behavior of different states of matter: solids, liquids, and gases. In solids, particles are closely packed and vibrate in place. In liquids, they are more loosely arranged and can slide past each other. In gases, particles are far apart and move freely, filling the available space.