Science Projects & Models

AIR BATTERY


List of materials:
This is the minimum list of material you need for your experiment.

1. Miniature light bulb (low voltage, low current)
2. Miniature base for light bulb
3. Pair of insulated solid copper wire AWG=20
4. Pair of alligator clips
5. Magnesium Electrodes
6. Iron Electrodes
7. A cup of saltwater
   
8. Screws for the miniature base.   

Additional optional materials you may use:

1. A wooden board to mount the miniature base (light holder)
2. Plastic container about 4" x 4" x 4"
3. Hydrogen Peroxide

  Procedure:

1. Remove the plastic insulation of about one inch from both ends of the wires. 
2. Loosen the screw on both contacts of the bulb holder. Place one end of the red wire under one screw, make a loop and then tighten the screw. Place one end of the black wire under the other screw, make a loop and then tighten the screw. 
3. Pass the open end of the red wire through the arm of the red alligator clip and secure it under the screw.
4. Pass the open end of the black wire through the arm of the black alligator clip and secure it under the screw. 
5. Screw the light bulb on the miniature base.
6. Connect the red alligator clip to the iron electrode and secure it on one side of the plastic container or the cup.
7. Connect the black alligator clip to the magnesium electrode and secure it on the opposite side of the container. (You may need to hold them by hand or use a small tape to hold them in place on the side of the container.
8. In another pitcher, prepare some strong, warm salt water. Add enough salt so at the end some salt will be left at the bottom of the pitcher.
9. Transfer the salt water from the pitcher to the container. 
10. At this time, if all the connections are secure and the electrodes are large enough, you should get a light.

 How can I get more light?

1. Make sure your electrodes are not touching each other.
2. Make sure there is nothing blocking the space between the electrodes.
3. Make sure that the alligator clips are not touching the salt water.
4. Both electrodes must have the maximum possible surface contact with salt water.

 

The test tube electrodes (magnesium electrodes in test tubes) are formed like a spring. This provides the largest possible surface contact. For Iron electrode you may use steel wool. Steel wool has a very large surface contact. A steel screen may work as well.

You may notice that you will get more light if you stir the solution or if you remove the iron electrode and insert it back again. Such actions provide oxygen to the surface of the iron.

In this case you may add some oxygen (in the form of hydrogen peroxide) to the salt water. That should immediately increase the light.