Electricity from a Lemon
Name______Per_____
Due by Thursday, April 23rd
EXTRA 1 PT CREDIT IF TURNED IN BY END OF PERIOD
Purpose: Can electricity be produced from a lemon, wiring to carry current, and some copper and zinc nails?
Pre-lab Questions: answers can be found in the blue packet.
1. Define the following words:
Conductor
Electrolyte
Direct current
Voltage
2. What produces the chemical energy in an electrochemical cell?
3. What is chemical energy changed into in an electrochemical cell?
Procedure:
1. Roll a lemon back and forth across a table or other flat surface while applying light pressure. The pressure will break the cellular structure of the lemon.
Experiment 1
2. Insert two zinc nails into the side of the lemon about 2 cm apart.
3. Connect one lead to one zinc nail and to one lead from the voltmeter. Connect the other lead to the other zinc nail and to the other lead from the voltmeter. Turn the voltmeter to 20 V range DC. Flip the switch to on. Record the voltage ______.(make sure you include negative sign if it appears).
4. Switch the leads to the voltmeter and record the voltage again.______.
Experiment 2
5. Replace one of the iron nails with a copper nail. Move the leads until you get a positive voltage. Record the voltage______.
6. Was there more or less voltage with the iron and zinc nails compared to the two zinc nails?______
What explanation do you have for this result?
Experiment 3
7. Move the nails about 4 cm apart and record the voltage again______.
8. Was your voltage the same, higher, or lower for the nails 2 cm apart compared to 4 cm apart (comparing step 5 with step 7)?______
Experiment 4
9. Take another lemon, copper, and zinc nails and set up as in step 5. Try to put the two lemons in a series circuit. Use your third lead to do this. You will know you have succeeded when you have twice the voltage.
What is the voltage you measured?______
10. Now show your set-up to your teacher before you disassemble the components.
11. Switch the leads between the two lemons (copper to copper between the two lemons instead of copper to zinc). Voltage recorded.______
12. Take apart your set-up and put all parts in the plastic container.
13. Rinse the nails, dry them, and put them in the beaker you found them.
14. Make sure your voltmeter is off.
Discussion questions. Help can be found in your blue packet.
1. What kind of electrochemical cell is the lemon/nail set-up?
2. Compared to a car battery, what takes the place of the sulfuric acid in the lemon/nail set-up?
3. What was the electrolyte in your lemon-nail set-up that provided a path for the electrons within the lemon?
4. Trace the path of electrons from the positive copper nail through the voltmeter, through the zinc nail, through the lemon, and back to the copper nail. Draw a picture for this.