The falling leaves of Autumn

One of the most common questions I am asked when teaching plants is why do the leaves of deciduous trees change colour before they fall off in autumn. To answer that question I have come across this excellent video: Within subtopic 2.9 you will also have opportunity to separate and identify the photosynthetic pigments from the leaves of a plant (spinach leaves are good): carotene, xanthopyll and chlorophyll through paper chromatography (Practical 4). The following is a virtual run through of the experiment ...