Here's why:
* Kinetic Molecular Theory: This theory states that matter is made up of particles (atoms or molecules) in constant motion. The higher the temperature, the faster the particles move.
* Temperature as Average Kinetic Energy: Temperature is a direct measure of the average kinetic energy of the particles in a substance. Kinetic energy is the energy of motion.
* Increased Motion, Increased Temperature: As the speed of particle motion increases, the average kinetic energy increases, leading to a higher temperature.
Examples:
* Heating a substance: When you heat a substance, you increase the kinetic energy of its particles, causing them to move faster and the temperature to rise.
* Boiling water: When water boils, the particles have enough kinetic energy to overcome the attractive forces holding them together in the liquid state, and they transition into the gaseous state (steam).
* Cold substances: Substances at low temperatures have particles with lower kinetic energy and therefore move slower.
It's important to note that temperature is a measure of the *average* kinetic energy. Even at the same temperature, individual particles can have different speeds.
