Specific heat

Specific heat capacity often varies with temperature, and is different for each state of matter. Liquid water has one of the highest specific heat capacities among common substances, about 4184 J⋅kg⋅K at 20 °C, but that of ice, just below 0 °C, is only 2093 J⋅kg⋅K. The specific heat capacities of iron, granite, and hydrogen gas are about 449 J⋅kg⋅K, 790 J⋅kg⋅K, and 14300 J⋅kg⋅K, respectively. While the substance is undergoing a phase transition, such as melting or boiling, its specific heat capacity is technically undefined, because the heat goes into changing its state rather than raising its temperature.