Potted plant. Image credit hotstyledesign.com

Potted plant. Image credit hotstyledesign.com

ZIMSEC O Level Combined Science: The test for starch

Aim: To test whether light is required for the photosynthesis process.


A potted plant, cardboard or aluminum foil, scissors, paper clips or tape, equipment for the start test.


  1. De-starch the green plant by placing it in the dark for 24 hours.
  2. Cut out a shape using foil or cardboard to partly cover one leaf.
  3. Attach the cover to the leaf using clips or tape. Make sure it is firmly attached and does not fall off.
  4. Place the plant in the light for a few hours.
  5. Test the covered leaf for covered leaf for starch.
  6. Record the results.


  • Only the uncovered part of the leaf tests positive for starch.
  • This is because light is required in order for the photosynthesis process to take place.

To access more topics go to the Combined Science Notes page.