By Jonathan Crowe
After the greyness of winter, the arrival of spring is heralded by a splash of colour as plants emerge from the soil, and trees seemingly erupt with leaves. Soon, much of the countryside has moved from being something of a grey, barren wasteland to a sea of verdant green. But why is it that so much vegetation is green? Why not a sea of red, or blue? To answer this question let me take you on a colourful journey from the sun to within the cells of plant leaves.
As humans, our waking hours are punctuated by mealtimes: we must consume food on a regular basis if our bodies are to be able to generate the energy we need to survive. Plants, however, fuel their survival in an altogether different way. Plants don’t need to ‘eat’ as such; instead, they generate their own food supply. This manufacturing of food is powered by energy that plants capture from sunlight.
It might seem odd to say that sunlight contains energy, but our everyday experience shows this to be so: if we sit outside on a sunny day, our skin quickly becomes warm. This warmth is the result of our skin cells absorbing the energy contained in the rays of sunlight.
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