12. G4: Group 1 – How does the pH level of different citrus fruits affect their output power?
13.
Editor's Notes
Independent: The power output of citrus fruit (W) Dependent: The pH level of different citrus fruits (apples, oranges, lemons, grapefruit, limes [pH]) Controlled Variables : Species of the citrus fruits Mass of the citrus fruits Same wire when collecting data Same metals inserted into citrus fruit (copper and zinc) Actual digital multimeters used Constant insertion of pH probe (angle, length) Distance between zinc electrode and copper electrode Methods of Controlling Variables: The breed of the citrus fruits Use the same breed of a particular citrus fruit (Example: Only use Granny Smith apples for the category of testing ‘apples’) The mass of the citrus fruits Measure the mass of each citrus fruit and alter them (cut them up) to make sure they are of the same weight. Same wire when collecting data Make sure you use the same wire when collecting the data Same metal strips inserted into citrus fruit Make sure you use the same metal strips (zinc, copper) Actual digital multimeters used Make sure the same digital multimeters are used to avoid systematic errors Constant insertion of pH probe (angle, length) Make sure the pH probe is inserted in the same depth, angle for each citrus fruit. Distance between zinc electrode and copper electrode Ensure there is a constant difference (cm) between electrodes.
PROCEDURE Independent: The power output of citrus fruit (W) Dependent: The pH level of different citrus fruits (apples, oranges, lemons, grapefruit, limes [pH]) Controlled Variables : Species of the citrus fruits Mass of the citrus fruits Same wire when collecting data Same metals inserted into citrus fruit (copper and zinc) Actual digital multimeters used Constant insertion of pH probe (angle, length) Distance between zinc electrode and copper electrode Methods of Controlling Variables: The breed of the citrus fruits Use the same breed of a particular citrus fruit (Example: Only use Granny Smith apples for the category of testing ‘apples’) The mass of the citrus fruits Measure the mass of each citrus fruit and alter them (cut them up) to make sure they are of the same weight. Same wire when collecting data Make sure you use the same wire when collecting the data Same metal strips inserted into citrus fruit Make sure you use the same metal strips (zinc, copper) Actual digital multimeters used Make sure the same digital multimeters are used to avoid systematic errors Constant insertion of pH probe (angle, length) Make sure the pH probe is inserted in the same depth, angle for each citrus fruit. Distance between zinc electrode and copper electrode Ensure there is a constant difference (cm) between electrodes.
