Archimedes’ principle says that fluid creates a buoyant force when an object is submerged in it; the buoyant force equals the weight of the fluid that the object displaces. Pascal’s principle states that a change in pressure applied to an enclosed fluid is distributed to all parts of the fluid and the enclosure wall undiminished. Bernoulli’s theory states that for a steady flow, the speed, pressure, and elevation of an incompressible and nonviscous fluid is related. I would rank Bernoulli’s theory the most important as the relationship he discovered and expressed in a mathematical equation is used in modern-day household plumbing, a cornerstone of modern-day living. Next, I would choose Archimedes’ principle as it explains how boats remain afloat. This is an especially interesting concept when we consider the large barges carrying goods for import and export as well as massive Navy ships. This principle is a key concept in modern-day commerce and military protection of our coasts. Last, I would list Pascal’s principle as it explains modern-day hydraulic equipment that can take a difficult job and make it easier such as hydraulic lifts and presses.