Aim The experiment is aimed at testing the following hypothesis: light is necessary for the leaves of a young plant to become green. Method To do it, I took a plant and put it in the darkness. If the green colour fails to develop, I will conclude that light is necessary for it. However, there is something more that I must do: I must take a second plant and put it in the light. I need this second in order to provide a standard with which to compare the first plant. The second plant is called the control. Result In carrying out experiments it is essential that the two plants should be kept in exactly the same condition, except for light they receive. Interpretation The obtained results show that the plants should be kept in exactly the same conditions, except for the light. Conclusion My hypothesis was proved. The light is necessary for the leaves of a young plant to become green.