Final answer:
The elevation difference between water levels is a physics-related concept that requires understanding principles like pressure, density, and gravity. Examples provided involve mercury levels in U-tubes, sea level changes, and hydrodynamics affecting energy potential and climatic impacts on ocean waters.
Step-by-step explanation:
The question relates to concepts in physics, specifically fluid dynamics when measuring the elevation difference between water levels in various contexts. With several scenarios provided, one can approach the problem through principles of pressure, density, and gravity. For instance, the U-tube mentioned with mercury at different levels is a classic example where the difference in height corresponds to a pressure differential that can be calculated using the density of mercury and gravitational acceleration.
Similarly, discussions on sea levels pertain to historical geophysical evidence and current trends, which can be analyzed using concepts of buoyancy, density, and climatic impact on ocean waters. The impact of melting ice and evaporation, as discussed in the passages, also falls under this topic. Calculating the actual elevation difference requires understanding these concepts and applying mathematical formulae where necessary.
Mentioned details about water falling on land and being dammed, or the amplitude of a wave in relation to still water, are examples where the differences in water levels are associated with potential energy and relevant to hydroelectric power generation. Each scenario outlines situations where the elevation difference is crucial for understanding the underlying physical processes or environmental impacts.