An increase of pressure in a closed system due to heat and expanding of water is known as:

The correct identification of the phenomenon as thermal expansion is based on the fundamental principles of fluid dynamics and thermodynamics. When water is heated in a closed system, it expands. This expansion generates an increase in pressure, as the volume of liquid is constrained by the walls of the container. This relationship between temperature and volume in a confined fluid is a crucial aspect of how liquids behave when subjected to heat.

In practical applications, understanding thermal expansion is important for designing systems that can accommodate fluctuations in pressure and avoid damage. For instance, fittings, pipes, and valves must be rated to handle the increased pressures that arise from thermal expansion to ensure safety and functionality.

In a closed system, if the pressure generated by thermal expansion exceeds the system's design limits, it can lead to failures, leaks, or other hazardous conditions. Thus, recognizing thermal expansion as the cause of increased pressure is essential for those working with plumbing and hydraulic systems, as it impacts how systems are engineered to manage these pressures effectively.