Increasing the diameter of a manometer does not affect the height difference or individual heights of the liquid, as pressure, density, and gravity remain constant. The relationship defined by pressure equals density times gravity times height indicates that the individual heights will not change despite the increased diameter. The cross-sectional areas cancel out in the derivation of the equation, supporting this conclusion. Therefore, while the difference in height remains constant, the individual liquid levels do not fluctuate. This understanding is crucial for accurately interpreting manometer behavior in fluid dynamics.