Why are leaves green?

Leaves are green because they are full of a green substance called chlorophyll.

Chlorophyll is a plant’s food-maker. It catches sunlight and uses that energy to turn water and air into sugar. This process is called photosynthesis. The plant eats the sugar and grows.

Sunlight has many colours. Chlorophyll soaks up the red and blue light to use as energy, but it does not use green light. The green light bounces off the leaf — and that is the green we see.

In some countries, leaves lose their chlorophyll in autumn. The green fades and other colours that were hiding underneath — yellow, orange and red — appear.