Final answer:
On a cooling curve plateau, the released energy induces a phase change at a constant temperature rather than raising temperature, as seen when water turns from steam to liquid, or from liquid to ice.
Step-by-step explanation:
On a plateau section of a cooling curve, the energy released does not increase the temperature but leads to a phase change. During this part of the curve, the substance remains at a constant temperature while transforming from one phase to another. For example, when water cools, it reaches a plateau at 100°C as steam condenses to water, and another potential plateau at 0°C when water turns to ice. The energy released during these phase changes is known as the latent heat of transformation. It's the energy given off when molecules slow down and become ordered, as in the transition from liquid to solid (freezing), or from gas to liquid (condensation).
In terms of cooling curves, these plateaus represent periods where the temperature of the substance does not drop even though heat is being released. The energy is being used to break intermolecular bonds, changing the physical state rather than increasing kinetic energy. Hence, no temperature change is observed until the entire substance has completed the phase change.