Electrolysis - Making Hydrogen From Water

Materials

• photovoltaic cell (3V min) or 9-volt battery
• (2) pieces of aluminum foil 6 cm x 10 cm
• salt
• (2) electrical wires with 2 cm uninsulated on each end
• (2) paper clips
• small bowl--glass, ceramic or plastic
• water
• spoon

Background

Electrolysis is a technique used by scientists to separate a compound or molecule into its component parts. By adding electricity to water and providing a path for the different particles to follow, it can be separated into hydrogen and oxygen.

Procedure

1. Accordion-fold each piece of aluminum foil down the long way so that you have two pieces approximately 1 cm x 6 cm. These are going to be your electrodes.
2. Press each electrode flat.
3. Bend the top 1 cm of each electrode over to act as a hanger. They will be hung on the inside of your bowl.
4. Attach one end of each wire to the hanger of your electrode with a paper clip.
5. Dissolve salt into water at the ratio of one teaspoon salt for each 50 ml of water. Stir to dissolve the salt.
6. Hang the electrodes on the inside of the bowl so that they hang down into the water. They should hang a couple inches apart; do not let them touch during the experiment. Add more salt water if necessary.
7. Attach the other end of each wire to your photovoltaic panel or a battery. Make a note which electrode is attached to the positive and which is attached to the negative.
8. If using photovoltaics, take your electrolysis device outside into the sun.
9. Observe the electrolysis procedure and what is occurring at each electrode.