What happens to the specific heat of water as it changes state?

When water changes state, such as from solid (ice) to liquid (water) or from liquid to gas (steam), the specific heat does not remain constant in the way one might initially assume. However, in the context of water, the specific heat capacity effectively can be treated as constant during phase changes when discussing practical aspects of heat transfer and related calculations.

For example, during the melting of ice, energy is added to the system without raising the temperature of the ice until it is fully melted. This added energy goes into breaking the bonds between water molecules rather than increasing the temperature—demonstrating that the temperature (and thus the specific heat in a conventional sense) is temporarily unmodifiable despite the energy being provided. A similar phenomenon occurs during the boiling of water, where heat energy is used to convert liquid water into vapor without changing the temperature until the entire phase transition is completed.

It is important to note that while specific heat is treated as constant for practical calculations within a single phase (either solid, liquid, or gas), it can differ between these phases. However, when asked about the behavior during a state change, it is understood that the energy is involved in the transition rather than changing the temperature and reported specific heat of the substance.