“When life gives you lemons make a battery!” In this television clip from Mission Unstoppable with host Miranda Cosgrove, NASA JPL electrical engineer Kat Echazarreta demonstrates how four lemons can generate three volts of energy, powering an LED light.
She then levels up the lemon battery with four additional lemons and measures with the multimeter a second time.
What’s happening with the lemons to make the battery work? Echazarreta explains the charges of protons, neutrons, and electrons, as well as how the lemon’s citric acid, the zinc nail, and the copper wire interact. A summary and science activity from Science World:
“The source of electric energy in this demonstration is the combination of copper and zinc strips in the citric acid of the lemon.
“The citric acid of the lemon reacts with the zinc and loosens electrons. Copper pulls electrons more strongly than zinc, so loose electrons will move towards the copper when the electrodes are connected by wires. Moving electrons are called an electric current, which is what lights up the bulb.”
Try this activity at home or in class, and discover more with these variations:
“Experiment with other fruits (e.g. oranges, grapefruits, apples, peaches, pears). Which ones produce the highest voltage? Why?
“Experiment with replacing the electrodes with two copper strips or two zinc strips and try to light the bulb. Measure the voltage and explain the results.
“Experiment with replacing the electrodes with different metals (e.g. iron and magnesium). Which combinations of electrodes give the highest voltage?”
Then go even bigger with this demonstration from Mark Rober: A lemon-powered supercar and making the world’s largest lemon battery.
Plus, watch more battery videos, more lemon videos, and more LED videos on TKSST:
• How do batteries work?
• B is for Battery – Circuit Playground
• Use a 9-volt battery to break water into its elemental components
• Conductive copper dominoes topple to turn on this lamp
• The Lemonade Machine, an epic Rube Goldberg collaboration
• Electromagnetic Induction, an Alom Shaha Science Demo
• How to Make the World’s Simplest Electric Toy Train
• How to Make LED Origami
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