What does thermodynamics study?

Thermodynamics is a branch of physics that focuses on the relationships between heat, work, temperature, and energy. It specifically investigates how energy is transferred and transformed within a system of matter, including the various processes that underlie these changes.

The study of thermodynamics involves understanding laws that govern energy conservation, energy transfer, and the direction of thermal energy flow—from hotter to cooler areas, for example. As such, it analyzes systems in terms of energy states and transformations, ensuring that the principles can be applied across various scientific disciplines, including chemistry and engineering.

The other options focus on different areas of physics: wave motion pertains to the propagation of waves, light interactions concern optics and photonics, and sound behavior relates to acoustics. While all these areas are significant in their own contexts, they do not address the broader energy transformations and interactions that define thermodynamics.