A classroom suitable method to make electrolyte solutions of any strength for al-air or microbial fuel cells if a heat source is available. Along the way we will learn about calculating ratios, percentages and solubility of inorganic chemicals in water. Plus these solutions can be used with other projects to experiment with the role electrolytes play in fuel cells and batteries.
Our approach is very simple. It's trivial to make a fully saturated (100%) water solution. While we are using salt the same approach may be used with other soluble compounds to produce of variety of chemical dilutions.
Once you have a bottle of saturated solution, you can take a portion of it and dilute it down with distilled water (or even tap water if it's not important to be too exact) to any percentage ratio you desire from 1% to 99%, but you need to start with 100% solution in order to mix an accurate dilution.
While I will focus on common table salt the same techniques can be adapted to any of the inorganic compounds in the later step.