How did Joseph Black’s heat research contribute to later physics?

Joseph Black’s research on heat significantly influenced the development of physics through his experimental work on thermal phenomena, though his theoretical framework was eventually superseded.

His primary contributions include:

• Latent Heat: Black distinguished between temperature and the quantity of heat, identifying latent heat—the energy absorbed or released during phase changes like melting or boiling—without a change in temperature. This discovery was instrumental in the development of the steam engine, as his friend James Watt incorporated these principles into his own engineering improvements.1
• Specific Heat: By observing that equal masses of different substances require varying amounts of heat to achieve the same temperature change, Black founded the concept of specific heat. This laid the groundwork for later 19th-century discoveries, such as the Dulong-Petit law, which linked specific heat measurements to atomic weights.2
• Caloric Theory: Black championed the caloric theory, which posited that heat was an invisible, weightless fluid. While this theory was later discarded in favor of the kinetic theory of gases after James Prescott Joule demonstrated that heat is a form of energy, Black’s rigorous experimental methods provided a vital foundation for the study of thermodynamics.3