How do we determine temperature on the thermodynamics scale?

Temperature in thermodynamics is determined using the concept of thermal equilibrium, where two systems at different temperatures exchange energy until they reach the same temperature. This can be measured using various scales, such as Celsius, Fahrenheit, or Kelvin, often employing thermometers that operate based on the expansion of liquids or the resistance of materials. The absolute temperature scale, Kelvin, is based on the theoretical concept of absolute zero, where all thermal motion ceases. Additionally, thermodynamic temperature can be calculated using the ideal gas law or other equations relating to the energy of particles in a system.