This document describes an experiment using lemons to create a battery. Students insert zinc and copper strips into a lemon and connect them to a voltage sensor to measure the voltage generated. Combining zinc and copper produced the largest voltage of around 1 volt. The experiment aims to demonstrate that batteries generate electricity through redox reactions, with metals like zinc losing electrons and metals like copper gaining electrons. Multiple lemon batteries can be connected in series to generate enough voltage to light an LED.

1. Lemon battery

2. Lemon battery
Driving Question
What generates electricity in a battery?

3. Lemon battery
Procedure: Connecting
1. Open SPARKvue Software
2. Connect the voltage sensor and go to the digits display.

4. Lemon battery
Procedure
3. Roll the lemon on a table so that the juice can flow
easily.
4. Make two small incisions on the lemon about 3 cm
apart.
5. Insert a piece of copper and a piece of zinc into the
slits on the lemon.
Note: If the metals are not clean, polish them with a piece of
sandpaper or steel wool.

5. Lemon battery
Procedure
6. Use the alligator clip leads to connect the copper and
zinc metal pieces to the Voltage sensor.
7. Start data collection
Note: The negative or positive sign of the voltage indicates the
direction of the flow of electrons. If you have a negative voltage,
simply switch the red and black clips to the other metal.

6. Lemon battery
Procedure
8. If you have a positive voltage then you have made a battery! Record the voltage in Table 1.
Metal Combination Negative electrode
(metal at the black clip)
Positive electrode
(metal at the red clip)
Voltage (V)
Cu with Zn
Cu with Sn
Sn with Zn
Cu with Cu
Zn with Zn
Sn with Sn

7. Lemon battery
Procedure
9. In any battery, there is a positive (+) and negative (-) electrode. Electrons flow from the negative
electrode (black) to the positive electrode (red). Record the positive electrode and negative
electrode of your lemon battery in Table 1.
Metal Combination Negative electrode
(metal at the black clip)
Positive electrode
(metal at the red clip)
Voltage (V)
Cu with Zn
Cu with Sn
Sn with Zn
Cu with Cu
Zn with Zn
Sn with Sn

8. Lemon battery
Procedure
10. Test the remaining combinations of metals. Record the voltage and the positive and
negative electrode metals in Table 1
Metal Combination Negative electrode
(metal at the black clip)
Positive electrode
(metal at the red clip)
Voltage (V)
Cu with Zn
Cu with Sn
Sn with Zn
Cu with Cu
Zn with Zn
Sn with Sn

9. Lemon battery
Analysis
Metal Combination Negative electrode
(metal at the black clip)
Positive electrode
(metal at the red clip)
Voltage (V)
Cu with Zn
Cu with Sn
Sn with Zn
Cu with Cu
Zn with Zn
Sn with Sn

10. Lemon Battery
Questions
1. Which metal combination generated the largest voltage?
2. Which metal combination(s) generated the smallest voltage?
3. Based on your data, do you think that the type of metal has something to do with the voltage that
is generated?

11. Lemon Battery
Questions
4. The metal that is at the negative electrode is the metal that loses electrons. Of this set of metals
(Cu, Sn, Zn), which one is most likely to lose electrons?
5. The metal that is at the positive electrode is the metal that gains electrons. Of this set of metals
(Cu, Sn, Zn), which one is most likely to gain electrons?

12. Lemon Battery
Engineering challenge
1. Create a battery, or a combine a
series of batteries to light a small
LED. To create a series of
batteries, you need to connect the
positive electrode of one battery
with the negative electrode of
another battery (See the picture
below). You may need to work with
other groups to combine multiple
batteries.

13. Lemon battery
Engineering challenge
2. Which metal combination did you use?
3. How many lemon batteries did you use to generate enough electricity to light the LED.
4. Based on the number of lemon batteries, and the metal combination, what voltage do you
expect to be generated by the series of lemon batteries?
5. Use the Voltage sensor to measure the voltage of the series of lemon batteries.
6. How does the measured voltage compare to the expected voltage?