Mass balance for a water tank. (Part 1: A simple tank)
A basic understanding of Systems thinking is essential to understanding our complex society and everyday lives, and is important to anyone trying to understand systems in the natural sciences, economics, social sciences, etc. In this activity the student is introduced to several fundamental concepts related to all systems. These include equilibrium, time delay or response time, the relationship between system flows and accumulations, and feedback processes. Here we use a water tank with some water volume V, an inflow S, and some possible outflow via a hole in the bottom. This is an excellent analogy to a variety of real world systems. For example: air, water, or soil pollution, hydrology, home energy use, medication dosage rate and blood concentrations, or the buildup of psychological stress during an ongoing stressful situation.