• Question: Why do leaves change colour in different seasons?

    Asked by Resh@science to Chris, Hayley, Jimi on 17 Mar 2016. This question was also asked by Deeps 2005.
    • Photo: Jimi Wills

      Jimi Wills answered on 17 Mar 2016:

      The colour of leaves is normally green… and this is because of chlorophil. Chlorophil is a chemical that allows plants to use the sun’s energy to split up carbon dioxide from the air and use the carbon to make stuff. (they release the oxygen back into the air)

      Chlorophil is normally green because of the wavelength of sunlight that it absorbs – that is it absorbs the red and blue light, but not green. The green light gets reflected and your eye sees it.

      When the leaves die, the chlorophil starts breaking down, and no longer absorbs the red light… so the red light gets reflected and the leaves look red or brown or yellow, depending on the exact mixure of red and green they are reflecting into your eye.

    • Photo: Hayley Moulding

      Hayley Moulding answered on 17 Mar 2016:

      The colour leaves does change. When they are green it is because of Chlorophyll. Jimi is right. When the leaves die or start to degrade/ get less sunlight, the chlorophyll will break down itself and then there are changes in the light which is being reflected and absorbed. So because the amount of sunshine changes during seasons, there are changes in the colour of leaves.

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