The zeroth law of thermodynamics states that if any two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other. To understand this experimentally, consider three beakers filled with water at three different temperatures. After connecting beaker A with B and beaker B with C, heat transfer will take place. After a period of time, the water in beaker A arrives at thermal equilibrium with the water in beaker B, and the water in beaker B arrives at equilibrium with the water in beaker C. On recording the temperature of the beakers, a uniform temperature is observed in all three beakers, which corresponds to the zeroth law of thermodynamics. The most significant application of the zeroth law of thermodynamics is the different types of thermometers. When a thermometer is used to measure the temperature of a body, it attains thermal equilibrium by changing its own temperature. Thus, the measured temperature of the body is actually the temperature of the thermometer.