Make a Battery from Pocket Change

coins
  • Can you make a battery using coins?
  • What happens when the number of coins is wried?
  • Do some coins make better batteries than others?
  • Can you light an LED light with a coin battery?

Recommended Items:

voltmeter

  • Voltmeter
  • Vinegar and salt
  • Different types of coins
  • Paper towels
  • LED light with wires attached so that is con be connected to the coin battery stack

Concepts used:

  • Electricity
  • Voltage Potential
  • Current
  • Material
  • Batteries

Background:

Electricity is mode by e lectrons moving through materials from negatively r ich areas to positively roch areas. This flow of electrons is called current. Metals are interesting materials because they have free electrons that are mobile and can be used to generate current. In addition, metals can give up electrons or receive electrons depending on whether they are more negatively or posit ively rich.

Batteries are made by placing two different metals. one negatively rich and the other positively rich , in a solution (called an electrolyte) that, first, wi ll allow electrons to flow between the metals, and, second, will, to some extent , replenish the electrons lost in the negatively-rich metal. The two metal ends of the battery are called electrodes. The combination of t he electrodes and the electrolyte solution makes whot is called an electrochemical cell. When the bat tery is not connected to a device, the electrons will gather on one electrode, making it negatively charged, while the other electrode will become positively charged. Connecting the battery too device creates current as the electrons flow from the negative electrode, through the device (like o light bulb, o radio oro voltmeter), back to the positive electrode.

In this experiment, you will layer one type of metal, a salt-solution soaked cloth, and another type of metal to make o single battery cell. The salt-solution soaked cloth will enable the flow of electrons between the metals and will recharge electrons lost in the negatively rich metal. Individual battery cells con be stocked up (not e: do not place the soaked cloth between the cells) and the current produced by each of the cells will odd together to produce o pretty good battery.

Notice that since some metals have more free electrons to give up or to accept than others, some dissimilar metal combinations work better as batteries than others do.

Notes:

  • Vinegar and water can be used to remove dirt from coins
  • If the coin battery doesn’t work try adding more coins to the stack, and verify that the voltmeter leods are pressed firmly against the first and last coin in the battery stack. Make sure that there is good contact between the leads and the coins.
  • Make sure that the paper towel pieces are salty enough by touching them and tasting your finger. If not, soak them again in a stronger saltwater solution and repeat the layering process to make the coin battery work.

Read More:

How Things Work – Science Projects

Science Buddies