We will consider some very important questions about the process of modeling including why we model these systems on a computer, how to understand the meaning and significance of a model that is a simplification of the real world. I think you will see that computer modeling can be relatively easy, even fun, but it is not so easy to figure out how to interpret the results of these models - how much faith or skepticism is appropriate in considering the results. This is a simple, fairly precise definition that is worth thinking about carefully. A few examples will help. A bathtub is a simple example of a dynamic system.
Water flows into the tub through a faucet and leaves the tub through a drain.
The faucet and the drain represent processes that are related because they both involve water moving into and out of the same reservoir, which is the tub itself. The balance between the inflow through the faucet and the outflow through the drain determines how much water accumulates in the tub. If the inflow and outflow rates are the same, then there will be no change in the amount of water in the tub, so the system would appear to be unchanging and not a true dynamic system. Another example of a dynamic system is a pot of water set on a burner. In this case, energy, rather than matter, flows through the system.