Energy, Heat, and Temperature
Energy exists in many forms including chemical, electrical, mechanical, and thermal energy. Potential energy is stored energy, while kinetic energy is energy of motion. According to the Law of Conservation of Energy, energy cannot be created or destroyed, only transformed.
Heat is energy transferred from a higher temperature body to a lower temperature one. Temperature measures the average kinetic energy of particles in a sample - not the total energy. Temperature doesn't depend on sample size, while heat does.
Phase changes occur when matter changes from one state to another. These include fusion (solid to liquid), vaporization (liquid to gas), condensation (gas to liquid), solidification (liquid to solid), sublimation (solid to gas), and deposition (gas to solid). Exothermic processes release heat, making surroundings warmer, while endothermic processes absorb heat, cooling surroundings.
Everyday Application: When sweat evaporates from your skin, it's an endothermic process that absorbs heat from your body, helping you cool down on hot days!