Before you get to the fun "job" of making batteries from fruits and vegetables, design a science activity chart to show exactly how each fruit and vegetable battery was made and the result of using the battery. Provide a blank section to write the materials used to make each battery. Provide a blank section to write the steps taken to make the battery. Provide a blank section to write the results of the activity (e.g., the battery generated enough electricity to turn on the digital clock).
The science charts should be passed out to your students for each activity. The students can fill in the blanks and add pictures for each activity. You can also display a large science chart on your bulletin board along with photos showing each activity. The bulletin board science chart will serve as an excellent display and review of students' science activities -- not to mention provide a good conversation starter and reminder of their unorthodox power sources.
Through this activity, students will learn that a battery made with a lemon can generate enough electricity to turn on a digital clock. For this project, divide science groups into six to 10 children, depending on the materials that can be provided. Assemble two lemons (roll lemons to soften them and then make two shallow vertical cuts about 1-inch apart in the middle of each lemon), three copper wires, two large paperclips, two pennies, a digital clock and scissors. Attach one copper wire to one large paperclip and one penny. Attach the next wire to the other penny. Attach the last wire to the last paperclip. Students should push the paperclip that has the wire attached to the penny into one of the cuts in the first lemon and then push the attached penny into one of the cuts in the second lemon so that the two lemons are connected by the wires. Then they should push the single paperclip that is attached to a wire into the other cut of the first lemon. Finally, they should push the single penny that is attached to a wire into the other cut of the second lemon. Next, they should connect the two loose wires to the battery terminals of the digital clock, wrapping them tightly. The clock should turn on. (Don't forget to enter the materials used, the steps and results of the activity on the science chart.)
Through this activity, your students will learn that a battery made with a potato can generate enough electricity to change a voltmeter readout. For this project, divide science groups into six to 10 children, depending on the materials that can be provided. Provide each science group with science charts, a large potato, a galvanized nail, 4 inches of stiff copper wire, plastic, 12-inch rulers and a DC voltmeter which measures voltage without an electric charge transfer. Students should push the galvanized nail about 1½ inches into one end of the potato and the copper wire about 1½ inches into the other end of the potato. Then they should place the negative black probe of the voltmeter onto the galvanized nail and the positive red probe of the meter onto the copper wire. This should give the meter a readout of ½ volt. Next, students should move the nail and copper closer together on the potato to see if the meter readout changes. Finally, they should measure the distance between the nail and the copper wire and the changes on the meter.
Through this activity, your students will learn that a battery made with a grapefruit can generate enough electricity to turn on an LED light. Because it requires using exposed LED wires, you may choose to have your students be observers while you carry out this project. Roll the grapefruit in your hands to soften it. Push the galvanized nail and the copper nail into the grapefruit 1 inch deep and 2 inches apart; they should not touch inside the grapefruit. Remove enough insulation from the LED lights leads to expose the necessary amount of wire to wrap around the nails. Wrap one of the exposed wires around the galvanized nail and use electrical tape to secure it, if necessary. Wrap the other exposed wire around the copper nail with electrical tape to secure it, if necessary. When both wires are attached, the bulb will light up. (Have your students enter the materials used, the steps and results of the activity onto the science chart.) As a final review of students' efforts, place the science activity charts on your science bulletin board.