My project is on the making of a battery out of a potato. First I will need a regular sized potato. If it is too big then it can be cut in half and both halves can be used as two voltage sources. The juice in the potato is going to act as an electrolyde to produce the electron flow between the anode and the cathode wires. These are wires that will send the voltage through each wire to the other side of the potato battery or into another voltage source. Then I will need to make a small incision and insert a shiny penny into it to produce the anode. If the penny is not shiny then I will need to give it a gentle rub back and forth with a piece of steel wool to release some of the oxidations to get a good connection off of the cathode. Then on the other side of the potato I have to insert a steel nail. The penny will produce the anode and the steel nail will produce the cathode. It is really important that the penny and the nail (the anode and the cathode) do not touch because then the electric circuit can not pass through and the battery will not work.
Now I will need a multimeter turned on to the 2 volts range. We should attach the black wire to the cathode and the red wire to the anode. The battery should produce a pretty good voltage, and if you push on the nail and the penny and drive it into the potato a little bit more then the voltage on the multimeter should go up a little bit more.
If we get quite a bit more potato's and attach them all together with anode and cathode wires then the voltage should go up a lot. I will need an approximation of 18 to 20 potato halves to get the voltage up to 9 volts. At this point the potato battery should be able to boil water. If it boils the water then the battery was a success. All in all, in order to make a battery with a higher voltage then what you are already getting then all you would need to do is add more potato halves and attach them to the other potato's and the voltage should increase.