Research questions and hypothesis

As a good scientist should, I decided to construct my hypothesis before performing the experiment. The objective is to enable the independent and dependent variables to be clearly stated and to postulate the relationship between these two variables.

Hypothesis: Leaves change colour due to the change in leaf pigments. Anthocyanin and carotenoids are present in dead leaves, anthocyanin, chlorophyll and carotenoids are present in dying leaves and chlorophyll and carotenoids are present in healthy leaves. 

My main research question: How do leaves change colour from green to brown as they die?

Sub questions:

·       Is there any difference in the leaf pigments present in a healthy, dying and dead leaves?

If there is, what happens to the leaf pigments as a leaf dies? Do they automatically become absent or are they just hidden under the other leaf pigments