Download PHYSICAL SCIENCE 100 LAB

PHYSICAL SCIENCE 100 LAB
A LEMON BATTERY
INTRODUCTION: In this experiment we fabricate a simple one-cell battery from a lemon and two
metal strips.
PROCEDURE:
1. Roll a lemon on the table back and forth with the palm of your hand to “juice up the lemon
inside”. This procedure serves to break down some of the membranes in the lemon to permit
better flow of the ions produced inside the lemon.
2. Make two side by side slots in the lemon as shown in the sketch below.
3. Sand the surface of each of the three metal strips provided (Iron-Fe, Copper-Cu, Zinc-Zn)
and wipe clean with a paper towel.
4. Insert two of the strips into the lemon and attach alligator clip leads to these strips
(electrodes) as shown in the sketch.
_____Volts
_____Volts
______Volts
______Volts _____Volts
______Volts
5. Attach the clip leads to the probes on the voltmeter provided.
6. Observe the voltage reading and record it in the space above.
7. Repeat steps 4, 5, & 6 with the other metal strips. You will have to borrow strips from
another table to use two Fe strips, two Cu strips and two Zn strips.
8. Using the Cu-Zn combination lemon battery, connect a wire from one electrode of one
lemon battery to the opposite electrode of a lemon battery from the lab table across from you and
measure the voltage of the two lemon batteries (in series). (We will later connect the two
batteries in a parallel arrangement and try to drive a small motor.)
Record your voltage. _______Volts
Why might you want to do this in a practical application?
AFTER you build the electric motor in the next experiment, try to connect two lemon
batteries to your electric motor to see if you can get enough current to “drive” your electric motor.
Your instructor will explain how to do the connection if you need help.
Pre-Lab Questions:
1. What is voltage?
2. What is electronegativity?
3. How is the electronegativity related to voltage and current?
4. Do you think any of the above combinations will provide a higher voltage than the others? If
so, which ones? If not, why not?
Post-Lab Questions
5. Of the above combinations, which gave you the most voltage?
6. Of the above combinations, which gave you a zero or close to zero voltage reading?
7. Do you think the voltage reading depends on what materials are being used? Explain your
answer.
8. How does electronegativity of different materials play a role in this experiment?