Connect copper wires to the positive and negative terminals of a 9-volt battery. Connect the end of each wire to copper strips. Immerse each strip in a beaker of salt water. Use distilled water and a 10 percent solution of salt to create an electrolyte solution. Hydrogen will collect around the cathode, the positively charged copper strip. Chlorine gas will collect around the anode, the negatively charged copper strip.
Roll a lemon on a hard surface to create juice within the lemon. Insert two metal strips into the lemon, one copper and one zinc. Use a voltmeter to measure the voltage or amount of electricity produced by the strips. A conductive solution of acid or salt base will produce electricity because the reaction between the electrodes and the solution creates the continual charge.
Place six strips of zinc wire on top of six strips of copper wire. Separate each set of strips with filter paper soaked in a salt water electrolyte solution. Connect a cable to the zinc strip at the top of the pile of strips and to the copper strip bottom of the pile of strips. Use a voltmeter to measure the voltage. The voltmeter should measure 6.6 volts or 1.1 volts per pair of elements. This homemade battery can power a clock.
Fill two beakers of water with an electrolyte solution. Place a copper strip in one beaker and a zinc strip in the other. Connect each strip to a voltmeter. Bend a small rubber tube into a "U" shape, fill it with saline solution and plug each end with cotton balls. Place the ends of the rubber tube, cotton ball side down, into the electrolyte solution of each beaker. The saline bridge acts as a barrier between the two different electrolytes while allowing the flow of the electrical charge.