Thermal Physics · Physics

Temperature can stay constant while energy flows.

During a phase change, added energy rearranges microscopic structure instead of raising temperature.

This topic

Phase Changes and Latent Heat

Use heating curves and latent heats to track energy exchange across melting, boiling, and more.

Concept

Phase transitions

A phase transition changes the state of matter (solid, liquid, gas) at characteristic conditions.

Quantity

Latent heat of fusion and vaporization

Latent heat is the energy required per unit mass to change phase at constant temperature (under typical conditions).

Graph

Heating curves

A heating curve shows how temperature changes as energy is added, including flat regions during phase changes.

Accounting

Energy exchange during phase changes

Many problems combine warming/cooling segments with one or more phase changes—solve by splitting into steps.

Practice

Practice & Exercises

Practice multi-step heating/cooling problems that mix temperature change and phase change.