What does the term "heat transfer" refer to when calculating temperature changes?

The term "heat transfer" specifically refers to the movement of heat energy from one body to another. This fundamental concept in thermodynamics describes how thermal energy is exchanged between physical systems and can occur through conduction, convection, or radiation.

In the context of temperature changes, understanding heat transfer is crucial because when heat is transferred to or from an object, it causes the temperature of that object to change. For instance, if a hot object transfers heat to a cooler one, the temperature of the hot object decreases while the temperature of the cooler object increases until thermal equilibrium is reached.

The other options focus on aspects that do not directly address the concept of heat transfer. Maintaining temperature, reading pressure gauges, and applying cooling methods pertain to the management and control of systems but are not the defining characteristic of how heat energy moves between bodies.