Related Links

  • Science Fair Project Guide

Project Summary

Difficulty  1  –  2 
Time required Very Short (a day or less)
Prerequisites None
Material Availability Readily available
Cost Very Low (under $20)
Safety No issues


Share this Project Idea!


Facebook Twitter Delicious Digg MySpace |More Services


Donate to Science Buddies

Abstract

Batteries are expensive, but you can make one for exactly 24 cents! In this experiment, you will make your own voltaic pile using pennies and nickels. How many coins in the pile will make the most electricity?

Objective

In this experiment, you will make a simple battery out of coins and test if the number of coins in the pile will affect the amount of electricity produced.

Introduction

You might think that batteries are a modern invention, but batteries were one of the first ways of making electricity. Alessandro Volta discovered the first electric battery in 1800. He made a giant stack of alternating layers of zinc, blotting paper soaked in salt water, and silver. This early design for a battery became known as the voltaic pile.

Physics Project Idea - voltaic pile
This image shows the structure of a voltaic pile, which is the first design of a battery that's used to make electricity. It was discovered by Alessandro Volta in 1800. (HowStuffWorks.com, 2007.)

How does a voltaic pile make electricity? The key to electricity is the movement of electrons. In a voltaic pile, electrons move from one metal to the other through the saltwater solution. The saltwater solution is called an electrolyte, and it contains ions in solution from the dissolved salts. An ion is a group of atoms that carries a positive or negative electric charge. The ions react with the metals, causing an electrochemical reaction, a special kind of chemical reaction that makes electrons.

The two types of metals in a voltaic pile are called electrodes. Since there are two kinds of metals, one metal reacts more strongly than the other, which leaves an electrical potential difference, also called (voltage,) between the two types of metals. One metal becomes positively charged (the positive electrode) and the other becomes negatively charged (the negative electrode). This causes electrons to move, creating an electrical current (which is measured in amperes), and then you have electricity!

In this experiment, you will make your own version of the voltaic pile using two different types of coins and a salt-vinegar solution. How does a voltaic pile made of money work? Since each coin is made up of a different metal, one metal reacts more strongly than the other, which leaves an electrical potential difference (voltage) between the two types of metals. The question is, how will different numbers of coins affect the amount of electricity produced? By making piles with different numbers of coins and measuring the voltage and current produced, you can test the effect of changing the number of coins in the piles

Terms, Concepts and Questions to Start Background Research

To do this type of experiment, you should know what the following terms mean. Have an adult help you search the Internet or take you to your local library to find out more!

Questions

Bibliography

Materials and Equipment

Disclaimer: Science Buddies occasionally provides information (such as part numbers, supplier names, and supplier weblinks) to assist our users in locating specialty items for individual projects. The information is provided solely as a convenience to our users. We do our best to make sure that part numbers and descriptions are accurate when first listed. However, since part numbers do change as items are obsoleted or improved, please send us an email if you run across any parts that are no longer available. We also do our best to make sure that any listed supplier provides prompt, courteous service. Science Buddies receives no consideration, financial or otherwise, from suppliers for these listings. (The sole exception is any Amazon.com or Barnes&Noble.com link.) If you have any comments (positive or negative) related to purchases you've made for science fair projects from recommendations on our site, please let us know. Write to us at scibuddy@sciencebuddies.org.

Experimental Procedure

  1. In a small bowl, mix together 1/4 C. of vinegar (electrolyte) and 1 Tbsp. of salt (ions).
  2. Using scissors, cut up a paper towel into small squares, each approximately 1 cm x 1 cm.
  3. Place the small squares to soak in the bowl of salt-vinegar solution, and set them aside.
  4. Gather some pennies and nickels, wash with a mild detergent (like dish soap), and dry. This is just a preliminary step to remove dirt and grime.
  5. Start building your stack on a dry paper towel on your plate. Put down a penny first, then place a square of vinegar-soaked paper towel on top, and then add a nickel. Keep repeating the layers until you have a stack of four coins (alternating pennies, wet paper towel pieces, and nickels), making sure you end with a nickel on top.
  6. Attach the leads of the multimeter to the two ends of the battery by touching one lead to the penny on the bottom and the other to the nickel on the top. Measure the voltage produced by your battery (in millivolts, mV). You can also measure the current produced (in milliamps, mA).
  7. Repeat the experiment, each time building a battery with a different number of coins. One important rule is to always start with a penny and end in a nickel, so the number of layers of pennies and nickels will always match. Why do you think this is necessary?
  8. Record your data in a data table like the one below:

    Number of pennies Number of nickels Voltage (mV) Current (mA)

  9. Make a graph of your data. What trends do you observe?

Variations

Credits

Sara Agee, Ph.D., Science Buddies

  • StyrofoamTM is a registered trademark of The Dow Chemical Company.


    Last edit date: 2008-02-06 20:00:00


    Career Focus

    If you like this project, you might enjoy exploring careers in Energy & Power.

    Nuclear Engineer
    Nuclear engineers harness the power of the atom to help solve large and difficult problems facing humanity. They design power plants that create energy to power homes and businesses without producing greenhouse gases. They develop machines that image the human body and destroy cancer cells, sterilize food and medical equipment, and create new pest or drought-resistant seeds. They work to make the world a better place.
      Power Distributors and Dispatcher
    Think of all the things in your home or school that use electricity, like the lights, TV, refrigerator, washer, microwave, music players, computer, and electronic devices. Now think of how you feel when the power goes out, even for just a moment. Power plant distributors and dispatchers have an important job—they work to keep electricity flowing to homes and businesses by carefully watching and planning for problems like big storms that could damage transmission lines, heat waves that cause a big surge in demand for power, or normal construction work, which could take transmission lines out of service.

    Power Plant Operator
    No matter what time of the day or night, or what the weather is like, power plant operators work to ensure that homes and businesses have a reliable source of power. They switch the plant generators on and off, as needed, and monitor and maintain generators, turbines, and pumps to prevent failures.
      Nuclear Power Reactor Operator
    One in five United States homes and businesses is powered by nuclear power, and nuclear power reactor operators are the people who ensure that those reactors are operating safely and efficiently at all times. They monitor all equipment continuously, and implement procedures if malfunctions are observed. They also control and adjust the amount of power being generated, and the reactor coolant temperature as power demands change through the day and during weather events, like heat waves.




    Join Science Buddies

    Become a Science Buddies member! It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives.


    Support Science Buddies

    If this website has helped you, won't you consider a small gift so we may continue developing resources to help teachers and students?

     



  •  

    Science Buddies gratefully acknowledges its Presenting Sponsor
     
    It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives.


    Science Fair Project Home      Our Sponsors      Partners      About Us      Volunteer      Donate      Contact Us      Research Grants & Outreach      Site Map

    Science Fair Project Ideas      Science Fair Project Guide      Ask an Expert      Blog      Teacher Resources      Parent Resources      Student Resources      Science Careers      Join Science Buddies     


    Privacy Policy Science Buddies

    Copyright © 2002-2010 Kenneth Lafferty Hess Family Charitable Foundation. All rights reserved.
    Reproduction of material from this website without written permission is strictly prohibited.
    Use of this site constitutes acceptance of our Terms and Conditions of Fair Use.