The three phases of water (ice, liquid water, and water vapor) can coexist at a single pressure and temperature known as the triple point The zeroth law of thermodynamics states that when two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system C , then A is also in thermal equilibrium with C

The three main temperature scales are Celsius, Fahrenheit, and Kelvin. Temperature is operationally defined as the quantity measured by a thermometer.

temperature — functionally defined as a quantity measured by a thermometer, which, at least for most of the systems discussed in this chapter, reflects the mechanical energy of particles in…. heat — energy transferred solely due to a temperature difference. thermal equilibrium — condition in which heat no longer flows between two objects that are in contact; the two objects have the same temperature. zeroth law of thermodynamics — law that states that if two objects are in thermal equilibrium, and a third object is in thermal equilibrium with one of those objects, it is also in thermal equilibrium with the….