The power supplied by the lemon cell is maximized at a salt concentration somewhere between 0.1 M, where the average internal resistance is 122 Ω and the average open-circuit voltage is 1.64 V, and a 0.5 M salt concentration, where the average internal resistance is 94 Ω and the average opencircuit voltage is 1.56 V. The power delivered by the lemon cell as a function of time for four different lemon juice dilutions with a salt concentration of 0.5 M are shown in Figure 5. The effect of dilution on the supplied power is clearly seen in this figure where each of the diluted lemon juice solution cells provides more power than the undiluted lemon juice cell. The 75% lemon juice solution produces the highest energy delivery over the twenty minute experiment at 7.5 W s. There appears to be little difference between the 50% solution at 7.0 W s and the 25% solution at 6.9 W s over twenty