How to Make a Lemon Battery Clock

Lemons can provide the "juice" needed to power a clock.

Creating a lemon battery clock is an excellent way for children to learn about how a battery works. The purpose of the project is to show how a battery is simply made of two different metals suspended in an acidic solution. With the help of adult, a child can make a "citrus cell" with materials that are easy to find at the hardware store and supermarket. Make this project for fun or as part of a science fair presentation.

Things You'll Need

• 1 small LCD clock (that runs on a AAA battery)
• 3 lemons
• 3 2-inch galvanized nails
• 3 pieces of uncoated stiff copper wire (2-inches in length, ½-inch in diameter)
• 4 electrician's clips
• Black permanent marker
• Tape

Instructions

1. Label each of the lemons "1," "2," and "3" with the black permanent marker.

2. Insert one nail into one end of each lemon, pushing the nail down into the fruit.

3. Insert a copper wire into each lemon, on the side opposite of the nail, by pushing the wire down into the fruit.

4. Use an electrician's clip to connect the nail in lemon No. 1 to the copper wire in lemon No. 2.

5. Connect the nail in lemon No. 2 to the copper wire in lemon No. 3 with another electrician's clip.

6. Attach the third electrician's clip to the copper wire in lemon No. 1; leave the other end of the clip loose. The copper wire will serve as the positive (+) terminal of the lemon battery.

7. Attach the fourth electrician's clip to the nail in lemon No. 3; leave the other end of the clip loose. The nail will serve as the negative (-) terminal of the lemon battery.

8. Open the battery pack of the LCD clock to remove the AAA battery from its compartment.

9. Carefully remove the entire backing of the LCD clock to expose the wires within it. Do this by removing the screws on the back of the clock. Sometimes, however, the back of the clock will simply snap off.

10. Find the two wires connecting to the positive and negative points in the clock. These wires are black and red, and lead to the battery compartment. The red wire is for the positive (+) terminal. The black wire is for the negative (-) terminal.

    Find the part of each wire that enters the clock's battery compartment. The bottom part of each wire is already exposed; no cutting or stripping of wires is necessary.

11. Connect the unattached end of the electrician's clip on lemon No. 1 to the positive red (+) wire of the clock.

12. Connect the unattached end of the electrician's clip on lemon No. 3 to the negative black (-) wire of the clock. The clock should begin to work within a few moments.

Tips & Warnings

• If the clock does not begin to work within a couple of minutes, make sure all the connections in the lemons are secure. If they are and the clock still does not work, try adding more lemons with a copper wire and nail in them to make a stronger circuit.

• An adult should always supervise a child that is doing this project.

References

• Family Fun: "Lemon-Aided Circuits"
• Hila Road: "Lemon Battery"
• Energy Quest: "Lemon Power"