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How to Make a Lemon Battery
Electricity experiments are popular with the kids. However, it is not always true that electricity experiments need complex circuitry and powerful batteries. For starters, the lemon battery science project is ideal to let the young learners know the basics. Besides, they will be thrilled when low power bulbs light up as a result of their efforts. The project requires close adult supervision.
Lemon Battery Experiment
It is possible to produce electric current using the acidic properties of lemon. When you attach two electrodes to a lemon and touch your tongue to both of them at the same time, it completes an electrical circuit, making an electric current pass through the tongue, giving it a tingling sensation or a metallic taste.
- 18 gauge copper wire or a copper penny
- Steel paper clip, a small strip of zinc or a galvanized nail
- Wire stripper or clipper
How to Make a Lemon Battery
- Use the wire strippers to strip off about 2.5 inches of plastic insulation from the copper wire. Then cut that piece from the main roll. This serves as the positive electrode or the cathode. If you are using a penny, make a small slit in the lemon with a knife before placing a penny snugly within it with about a third of it exposed.
- Straighten up the steel paper clip carefully. Cut the same length from it as the copper wire. Either this or the galvanized nail or zinc strip is the anode or the negative electrode.
- Use the sandpaper to make the edges of the two electrodes smooth as they would serve as the junction points of the electrical circuit. If you are using zinc as an electrode, scratch its surface lightly to expose a fresh surface.
- Roll the lemon gently on a table to loosen the soft pulp and allow the juice to flow inside. Be careful not to rupture the skin of the lemon, though.
- Insert the copper wire by 1 inch into the lemon.
- After ensuring that your tongue is moist with saliva, touch it to the copper wire. Make an observation regarding what you feel.
- Insert the paper clip, zinc strip or nail into the lemon keeping a distance of ¼th inch from the first insertion point. Ensure that the two electrodes do not touch each other at any point.
- Now, make contact with your moist tongue to both the exposed ends of the electrodes at the same time. Make an observation again regarding the sensation in your tongue.
How Many Volts Does a Lemon Battery Produce
It depends on what metal wire you are using for the anode and cathode. You can take notes of the amount of voltage produced by using different wires so you can monitor the outcome in future.
Though the voltage produced in this experiment is near about a volt that is well within safety limits, those of you who do not desire any physical contact with the equipment can test the electric current and voltage by connecting a multimeter to the electrodes. They need to connect the leads of the device with the lemon battery with the help of alligator clips.
Lemon Battery Science Fair Project Video
How Does a Lemon Battery Work?
A battery converts chemical energy into electrical energy. The electrodes here are made to come into contact with the lemon juice that is nothing but citric acid, an electrolyte. As a result, a chemical reaction ensues and electrons start to get accumulated at the anode. However, positive charges build up at the cathode. As soon as a conducting material (your tongue) establishes a connection between the electrodes, the electrons get a chance to flow from the cathode to the anode forming an electric current. When you touch your tongue to the copper wire only, before connecting the zinc strip, no reaction occurs. Hence, you feel nothing on your tongue in the absence of electric current.
Things You Can Try for Better Results
You will find that the voltage produced by a single lemon powered battery is not enough to light a small bulb or LED. However, if you connect a number of lemon batteries in series, you will find the resultant electricity sufficient to light an LED. Try that out by making around four to five lemon batteries and connecting the anode of one with the cathode of the next with a copper wire, for the entire set. Connect the LED bulb in between the copper wire and zinc strip left free at the extreme ends to see the results. A digital clock or calculator with its regular battery removed can also be made to work with this homemade battery.
You can plot a graph with the number of lemon batteries in the circuit as the independent variable (X-axis) and the voltage generated as measured by a multimeter, as the dependent variable (Y-axis). Check the nature of curve obtained. Instead of a lemon, you can try other acidic foods like potatoes, citrus fruits like orange or lime to make the battery.
Electricity projects give you immediately observable results and the quantities involved can be easily measured. Hence, kids will learn a lot in a fun way.
Published on December 1st 2015 by Papiya Dutta under Science Fair Projects. Article was last reviewed on 3rd November 2017.