text: The dynamic theory of these phenomena models them as systems that include an amphidromic point.
full_question: The dynamic theory of these phenomena models them as systems that include an amphidromic point. The namesake producing force of these phenomena is approximately ten to the seven times smaller than the force of Earth's gravity. A set of partial differential equations that govern these phenomena was developed by (*) Laplace. The equilibrium theory of these phenomena was first proposed in Newton's Principia Mathematica and models the Earth as a geoid. That theory allows for an intuitive description of their spring-neap cycle and their namesake bulge. Most places experience semi-diurnal ones. For 10 points, name these phenomena of which there are typically two "high" and two "low" every day.
first_sentence: The dynamic theory of these phenomena models them as systems that include an amphidromic point.
raw_answer: tides