Final answer:
For non-uniform containers, as the volume constantly increases, the water level might rise more slowly or remain constant, depending on the shape. During a phase transition like boiling, pressure stays constant at a certain temperature, as described by Charles's law.
Step-by-step explanation:
When the rate of change of volume is constant but the shape of the container is not uniform, the rate at which the water level rises may vary. For a container with sides that taper outwards (like a cone or a bowl), as volume increases, the water level will rise more slowly. However, if the sides are vertical (like a cylinder), the water level will rise at a constant rate as well.
As the volume increases at constant temperature during a phase transition, like from liquid to gas, the pressure remains constant. This is seen in behaviors such as boiling and condensation, where the substance can change state without changing temperature or pressure.
It's important to consider that real-world scenarios may not always directly align with these principles, and factors like temperature changes, external pressure, and heat input rate can influence the behavior. However, in a theoretical scenario where volume change is directly caused by temperature change at constant pressure, one would consider Charles's law to understand the relationship.