• Question: why do leaves change colour in autumn?

    Asked by SparklyUnicornGirl to Ajay, Kate, Kuntal, Pip, Reka on 14 Nov 2016. This question was also asked by Yusufmalik786.
    • Photo: Reka Nagy

      Reka Nagy answered on 14 Nov 2016:

      The reason leaves are green in the first place is because of chlorophyll, the molecule that traps sunlight to use it in photosynthesis, the process that turns carbon dioxide and water into sugars and oxygen with the help of sunlight. This is how plants ‘eat’.

      The leaves of most plants stop their food-making process when autumn sets in, as there is less sunlight for them to use because the days get shorter. No new chlorophyll is produced and the one that was in the leaves starts to break down. The green colour disappears, revealing beautiful hues like red, orange and brown.

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