The experiment is aimed at
testing the following
hypothesis: light is necessary
for the leaves of a young
plant to become green.
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.
In carrying out experiments it is essential
that the two plants should be kept in
exactly the same condition, except for light
The obtained results show that the plants
should be kept in exactly the same
conditions, except for the light.
My hypothesis was proved. The
light is necessary for the leaves
of a young plant to become