Thermodynamics is the branch of physics that studies the relationships between heat, work, and energy. It focuses on how energy is transferred and transformed in physical systems, helping to explain processes like combustion, refrigeration, and the behavior of gases. The field is governed by four fundamental laws, which describe how energy moves and changes form. These laws apply to various systems, from engines to biological organisms, and are essential for understanding concepts like entropy and temperature. Thermodynamics plays a crucial role in engineering, chemistry, and environmental science.