Temperature, thermal energy, and heat are related concepts in thermodynamics, but they have distinct meanings. Here's a breakdown of their key differences:
Temperature: Temperature is a measure of the average kinetic energy of the particles in a substance or system. It determines the direction of heat transfer, with heat flowing from higher temperature regions to lower temperature regions. Temperature is typically measured in units such as degrees Celsius (°C) or Kelvin (K).
Thermal energy: Thermal energy refers to the total kinetic energy possessed by all the particles in a substance or system. It takes into account the individual energies of the particles, including their motion, vibrations, and rotations. The thermal energy of a substance is directly proportional to its temperature. It is measured in units such as joules (J) or calories (cal).
Heat: Heat is the transfer of thermal energy between two objects or systems due to a temperature difference. When there is a temperature gradient, heat flows from a region of higher temperature to a region of lower temperature. Heat transfer can occur through conduction (direct contact), convection (through a fluid), or radiation (through electromagnetic waves). Heat is measured in units such as joules (J) or calories (cal).
In summary, temperature is a measure of the average kinetic energy of particles, thermal energy is the total kinetic energy of all particles, and heat is the transfer of thermal energy from one object or system to another.