At the end of 14-16 days count the number of seeds germinated in both light and darkness for each plant. If the germination percentage is essentially the same for both the dark and light exposed seeds, it would be correct to assume that the seed in question is not affected by exposure to light. If there is a significant difference between the dark and light exposed seeds then it would be correct to assume light did play a role. It is left to the student to explain the details of each and prepare conclusions for the experimental report. Additional Experiments Other evaluation methods besides germination can also be used, such as measuring the size of root and shoot portions of the germinated seed, or planting the germinated seeds and taking weekly measurements of height, width and leaf size on the plants.
Students can then determine the effects of sunlight on plant growth as well as seed germination.