The odor of a smelly shower drain can be eliminated by removing debris from the drain. Discarding the odor-causing material in the garbage outside the home ensures the smell does not invade other areas. Boiling water dissolves oils and grease deposited on the sides of the pipe in the drain, which add to the smell.
Luckily for us, Nernst derived an equation that allows us to determine at what point the two forces (chemical and electrical gradients) balance each other - in other words, at what point we have an ionic equilibrium.
This gradient is of interest as an indicator of the state of the cell through parameters such as the Nernst potential. In terms of membrane transport the gradient is of interest as it contributes to increased system entropy in the co-transport of substances against their gradient.