A Simple Pure Water Oscillator

In this paper we analyze the properties of a pure water oscillator by considering the pure water lake as a well mixed two layered system. While there is heating of and evaporation from the shallow top layer, the temperature of the deep bottom layer is assumed to be constant. By exploiting the nonlinear dependence of the density of pure water on temperature, we describe two complementary mathematical models to capture the vertical instability resulting from the variation of the density of the top layer with temperature.