Methods




Variables

Independent variable: Amount of coke and salt content
Dependent variable: The voltage produced
Constants:
  • The materials used to conduct electricity
  • The material of the cup
  • The type of coke
  • The voltmeter
  • The temperature of the surroundings
  • The temperature of the coke

Hypothesis

The greater the amount of coke, and the lesser the amount of salt added to the coke, the more the voltage is produced.

Testing how the amount of coke affects the voltage produced

  1. Start with an empty cup.
  2. Pour 100 ml of coke into the cup.
  3. Attach the zinc strip on one side, dipping it into the coke.
  4. Attach the copper strip on the other side, dipping it into the coke as well.
  5. Clip the aluminium and copper strips to the crocodile clip wires.
  6. Clip the other end of the crocodile clip wires to the voltmeter.
  7. Read the reading on the voltmeter.
  8. Repeat steps 1 to 7, 2 more times, but using 200ml, and 300ml of coke respectively.

Testing how the amount of salt affects the voltage produced

  1. Start with an empty cup.
  2. Pour 100 ml of coke into the cup.
  3. Attach the zinc strip on one side, dipping it into the coke.
  4. Attach the copper strip on the other side, dipping it into the coke as well.
  5. Clip the aluminium and copper strips to the crocodile clip wires.
  6. Clip the other end of the crocodile clip wires to the voltmeter.
  7. Read the reading on the voltmeter.
  8. Add 5 teaspoons of salt into the coke.
  9. Read the reading on the voltmeter.
  10. Repeat steps 8 and 9 2 more times.
  11. Repeat steps 1 to 10 2 more times, but using 200ml, and 300ml of coke respectively.

Risk Management

  1. As this experiment involves electricity,very slight electrocution is possible so use a dry glove when handling wires.
  2. As we might need to use scissors to cut the zinc and copper strips, handle scissors carefully.
  3. As the copper or zinc strip might be sharp, use caution when cutting them.
  4. This experiment involves acids although it is very mild, over concentration is possible. Use gloves when handling coke.
  5. As this experiment requires handling of liquids, spillage is possible. Clean up any spillage immediately.

Results

The amount of coke does not increase the amount of voltage. Salt added to the coke will decrease the voltage. So when making the battery, there is no need for too much coke, and no need for salt to be added to the code.