NAME PERIOD DATE

LEMON BATTERIES

Driving QuestionWhat generates electricity in a battery?

Materials and Equipment Zinc metal Voltage sensor Tin metal Leads with alligator clips Copper wire Lemons Steel Wool or sandpaper A light emitting diode (LED)

BackgroundEnergy cannot be created or destroyed, but it can be converted from one form to another. In this lab you will look at one factor that affects how chemical energy is converted to electrical energy.

SafetyFollow these important safety precautions in addition to your regular classroom procedures:

Wear safety goggles at all times.

Procedure

1. Open the Lemon Battery lab file from the experiments menu in SPARKvue under High School>Chemistry.

2. Connect the Voltage sensor and go to the digits display.

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.

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.

8. If you have a positive voltage then you have made a battery! Record the voltage in Table 1.

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LEMON BATTERIES

9. In a 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.

10. Test the remaining combinations of metals. Record the voltage and the positive and negative electrode metals in Table 1.

Copper with Tin

Zinc with Tin

Copper with Copper

Zinc with Zinc

Tin with Tin

Analysis Table 1: Lemon batteries

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

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?

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?

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LEMON BATTERIES

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.

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?

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