How to Make an Electric Charge Using Fruits and Veggies
Making a battery out of a piece of fruit or a vegetable is an excellent way to demonstrate properties of both chemistry and electricity for kids and adults alike. In order to get an electric charge you will complete an electric circuit, so electrons can flow freely from the negative end of the battery to the positive end. While many types of fruits could be used as the circuit's source of energy, this demonstration can be done more reliably with a large lemon, which is also more likely to be available.
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Things You'll Need
- Large lemons
- Galvanized nails
- Digital multimeter
- Alligator clips
- Small LED light
Instructions
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1
Squeeze and squish the largest lemon you can find, without piercing the rind. Squash it lengthwise a little. The objective of this is to break up the "juice vesicles" that constitutes the pulp of the lemon so the lemon juice can flow freely throughout the insides of the fruit.
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2
Insert the galvanized nail into the side of the lemon, close to the middle. Penetrate the rind and plunge the nail deep enough to stick out without having to be held in place.
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3
Insert a 1- to 2-inch length of bare copper wire into the same side of the lemon as the galvanized nail, close to the middle but on the other end. Make sure the copper wire and nail are suspended in the pulp without coming into contact with each other.
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4
Touch the negative side of the battery, or the galvanized nail, to the negative probe of your multimeter, usually the black probe.
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5
Complete the circuit by touching the positive side of the battery, or the length of copper wire sticking out of the lemon, to the positive probe of your multimeter, usually the red one. You might find pairs of alligator clips helpful as intermediary connections between the battery ends and the multimeter probes. At this point you should be able to see a reading on the display of the multimeter, proving that an electric circuit of approximately one volt has been completed. If you get a negative number, the probes are connected in the wrong order.
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6
Replace the multimeter with a very small LED. Connect the negative side of the battery (the galvanized nail) to the prong on the flattened side of the LED, and the positive side to the other prong. You may need to dim the lights in order to see any glow of the LED.
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7
Add a battery to the circuit by using alligator clips to connect two lemons together. Repeat Steps 1 through 3 for a second lemon. Add the lemon to the chain by connecting the copper wire of one lemon to the galvanized nail of the other. Make sure the galvanized nail of one lemon is connected to the negative side of the LED (the side with the flattened edge), and that the copper wire of the other lemon is connected to the positive side of the LED. While the LED should brighten considerably, you may still need to dim room lights to see it.
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Tips & Warnings
Take advantage of teaching moments. Explore the concept of circuit completion; talk about how electricity is everywhere.
References
Resources
- Photo Credit lemon image by Aleksei Volkhonsky from Fotolia.com
