11 fruit battery activities for kids

A fruit battery science experiment is fascinating for children while tackling electricity, a topic on the list of hard topics to teach. A fruit clock or homemade batteries using fruit juice or other liquids with electrolytes are fun and easy.

Safety note: Be sure to explain safety precautions to children. These experiments use acids and electricity. Eye protection should be used. Before and after this experiment, be sure to thoroughly clean hands. Disclaimer: All information provided on this site is for entertainment and education purposes only. Using any information from casabouquet.com is at your own risk.

The basic setup is two different metal electrodes inserted into a fruit. Use wire to connect the electrodes to a light, clock, or current-measuring device. OR make a voltaic pile by alternating discs of two metals with paper dividers and using fruit juice or another solution of electrolytes.  These 11 fruit battery experiments encourage children to ask questions about electricity, collect data, analyze, and share their findings.

1. A Battery That Makes Cents from Science Buddies
2. Generate Electricity with a Lemon Battery from Scientific American
3. Fruit battery experiment from Explorable
4. Fruit-power battery from Steve Spangler Science
5. Fruit batteries project from Crystal Clear Science Fair Projects
6. Lemon battery from PBS Kids
7. Recreate physics history: Build a voltaic pile from Arbor Scientific. Note the cool hack to get zinc disks!
8. Video: How to make a battery from a voltaic pile by Adam Kemp, high school teacher
9. Lemon battery from Kids Activities Blog
10. Hand battery from the Exploratorium
11. Lemon Clock from Creekside Learning

When trying a fruit battery activity, I always encourage children to make it into an experiment. There are several areas where variables can be changed.

Electrodes: provide copper, zinc, carbon, aluminum, and even magnesium. Copper and zinc are the traditional electrodes for a fruit or acid battery. Provide different thicknesses of these metals. You can also mark the metals at 1 cm intervals with a permanent marker so the children can measure the result as the electrodes are pushed into the fruit farther and farther. You can also use discs such as pennies, nickels, quarters, washers, or zinc disks pushed out of a galvanized electrical box. For a voltaic pile, you can use card stock, brown paper towels, or coffee filters for the separators.

Electrolyte: For fruit, try lemons, apples, and potatoes. Other citrus fruits will work, the children may find a difference between different types of apples (Gala vs. Honey Crisp?), and some have gotten carrots to work. You can also try different liquids such as Diet Coke, orange juice, sports drink, vinegar, and baking soda or salt dissolved in water. Use pH paper or a sensor to add measurement of pH to the experiment.

Measuring current: a favorite of my students is to light up an LED clock with the battery. You can also provide red and green LED lights or a bulb with wires cut from a fairy light string. A microammeter gives the ability to measure the actual current being produced.

What is the science?

Content: electricity, direct current, batteries, electric circuits, energy transfer, voltaic pile

A battery often has two conducting metals, the electrodes, and a solution with charged ions that can move, the electrolyte. The electrode called the cathode (positive, +) receives electrons, while the anode gives up electrons (negative, -). The electrical current is measured in amperes (or amps). This can be thought of as the number of electrons that pass through a point per second. The short leg of an LED light is the negative, and should be attached to the negative side of the battery. The long leg is positive, and should be attached to the copper side of your battery.

Resource links

• http://www.flinnsci.com/teacher-resources/safety/general-laboratory-safety/
  • General Lab Safety resources from Flinn Scientific. Be sure to check out the Student Safety Contract.
• http://engineering.mit.edu/ask/how-does-battery-work
  • How does a battery work? From MIT’s Ask an Engineer
• http://electronics.howstuffworks.com/everyday-tech/battery1.htm
  • How batteries work from How Stuff Works
• http://www.sciencebuddies.org/science-fair-projects/multimeters-tutorial.shtml
  • How to use a multimeter from Science Buddies

Let’s talk story

The apple battery was one of my middle schoolers favorite energy activities. It was exciting to see how long a clock would run off the juice of one apple. Most children had not had experiences with electricity. It was fun to work with batteries, wires, and bulbs to get the basics of electric circuits.

I’ll be looking for comments below, or contact me at lisa[at]casabouquet[dot]com.

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