Want to make a battery? All you need are several lemons, other fruits, or fruit juices,
two different kinds of metal, and some pieces of wire for connecting everything together.
Once you have those items, you need only a little knowledge of electrochemistry and
you’ll be ready to go.
How does a fruit battery produce electrical energy? The fruit itself is a container for a
solution of electrolyte. As you may know most fruit juice is acidic. The hydrogen ions
provide the conduction of charge through a lemon battery. Two dissimilar metal strips
are electrodes at which an oxidation reaction and a reduction reaction take place to
provide the batteries power source.
Two different chemical reactions take place at each of the metal strip electrodes. The electrode with the metal that is
more easily oxidized becomes the anode, the electrode at which the oxidation reaction occurs. The second electrode
becomes the cathode, and the reduction reaction proceeds at its surface. When these two reactions occur together,
in the same cell, they combine to produce a spontaneous redox reaction. This spontaneous reaction generates the
cell voltage of a battery by producing a different electrical potential and each electrode.
Oxidation
Potential
(V)
Easily Oxidized
Li
K
Ca
Na
Mg
Al
Mn
Zn
Cr
Fe
Ni
Sn
Pb
Cu
Ag
Hg
Pt
Au
Not Easily
Oxidized
3.04
2.92
2.87
2.71
2.37
1.66
1.18
0.76
0.74
0.44
0.25
0.14
0.13
-0.16
-0.78
-0.80
-1.20
-1.50
Using the information in the table to the left answer the following
questions:
1. What are three metals that are easily oxidized?
2. What are three metals that are not easily oxidized?
3. How does the oxidation potential relate to the ease of
oxidation of a metal?
4. Chemical cells depend on a difference of oxidation potential in
the two electrodes. Knowing this, would a battery made with a
nickel and a tin electrode be very effective? What would be a
better choice?
Now that you have an understanding of the way a battery works, lets
try to use different fruits and electrodes to make some batteries!
Instructions for the lab will be found at your lab station along with your
supplies. Be sure to read the instructions carefully so that your data
will be accurate. The data table below will be where you will record
your data.
Fruit
(electrolyte)
Lemon
Lemon
Lemon
Lemon
Lemon
Lemon
Lemon
Lemon
Lemon
Lemon
Lemon
Lemon
Orange
Orange
Orange
Orange
Orange
Orange
Orange
Orange
Orange
Orange
Orange
Orange
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Anode
(Red)
Aluminum
Aluminum
Aluminum
Zinc
Zinc
Zinc
Nickel
Nickel
Nickel
Copper
Copper
Copper
Aluminum
Aluminum
Aluminum
Zinc
Zinc
Zinc
Nickel
Nickel
Nickel
Copper
Copper
Copper
Aluminum
Aluminum
Aluminum
Zinc
Zinc
Zinc
Nickel
Nickel
Nickel
Copper
Copper
Copper
Cathode
(Black)
Zinc
Nickel
Copper
Aluminum
Nickel
Copper
Aluminum
Zinc
Copper
Aluminum
Zinc
Nickel
Zinc
Nickel
Copper
Aluminum
Nickel
Copper
Aluminum
Zinc
Copper
Aluminum
Zinc
Nickel
Zinc
Nickel
Copper
Aluminum
Nickel
Copper
Aluminum
Zinc
Copper
Aluminum
Zinc
Nickel
Prediction
Voltage
Follow Up Questions:
1. Which batteries produced the most electricity?
2. Knowing that we cannot make or destroy energy, where does the electrical energy come from?
3. Based on what you learned in class today design a battery that would be more effective then those that we tried in
class today.