The Penny Battery
Overview
Transform pennies and zinc washers into a battery that will power a light emitting diode
(LED).
Next Generation Science Standards
● NGSS MS-PS1-6 The transfer of energy can be tracked as energy flows through
a designed or natural
system.http://www.nap.edu/openbook.php?record_id=13165&page=94
● NGSS MS-PS3-2 Develop a model to describe that when the arrangement of
objects interacting at a distance changes, different amounts of potential energy
are stored in the system.
Key Concepts
Light emitting diode (LED)
Chemical energy
Batteries in series
Voltage
Multimeter use
Materials
● 3 Pennies – Pennies from before 1982 work best because they are 95% copper;
those made after 1982 are 97.5% zinc with a thin copper coating. Pennies made
in 1982 could be either zinc or copper.
● Cardboard
● Vinegar
● Scissors
● Plastic cup
● 3 5/16 inch zinc flat washers
● Red LED (available from Radio Shack)
● Electrical tape
● Multimeter
● 1 in by 3 in piece of aluminum foil
Duration
30 minutes
Grade Level
4-9
Safety Concerns
Vinegar is an irritant. Wear safety goggles.
Procedure
1. Trace around 3 pennies that have been placed on cardboard.
2. Cut the cardboard pieces so they are slightly bigger than a penny.
3. Soak the cardboard pieces in vinegar until they are saturated.
4. Place a zinc washer on one end of the aluminum
foil then stack a piece of vinegar soaked
cardboard followed by a penny. This is one cell
of the battery. . Use a multimeter to measure
the electric potential in volts by placing the
positive (red) lead on the top penny while the
black lead is placed on the aluminum foil under
the stack. You can also measure current draw in
milliamps.
5. Continue this pattern until the desired voltage is reached measuring the electric
potential after each cell.
6. Connect the negative lead of the LED (short leg)
to the zinc washer side of the battery and the
positive side to the penny.
7. Wrap the entire battery with electrical tape. The
LED should continue to shine.
Extension
The development of the wet cell battery has an interesting connection to biology.
Alessandro Volta, who invented the battery or Voltaic pile in 1800, was said to be
inspired by the torpedo fish. Capable of
electrocuting its prey; the torpedo fish uses an
organic structure to produce an electric shock. The
fish has electrocytes which are flat disk-like cells
that are stacked just like the copper and zinc disks
in the battery created in this activity. The more cells
that are stacked, the more the voltage produced.
Investigate the connection between the study of the
torpedo fish and the invention of the battery.