This model is a tank with an inflow and an outflow. The inflow is constant, the outflow is proportional to on the quantity in the tank. Finally, when the inflow is equal to the outflow, the quantity will stay the same.
- J = inflow
- Q = stored quantity.
- K*Q = outflow
- DQ = J - K*Q = change during a time increment
The graph shows the change of Q over a time period.
- Kitchen sink
- Steady leaf fall and creatures decomposing them.