An explanation of how leaves work as a plant's food factory, converting sunlight into food for the plant in a process called photosynthesis. We see the result of an experiment in which the leaves of a plant have been removed. What happens when the leaves of a tree get infected with a disease? A tree surgeon explains the tree can't produce food if the leaves die.

First broadcast:
8 October 2007

After watching this clip, students could be asked what they have learned about what a plant needs to live and grow. They should note that plants need sunlight in order to grow. Students could then conduct an experiment to find out what else a plant needs to grow. Three plant pots could be set up, each with one seed of the same plant planted in the same volume of soil in order to keep the test fair. They could then change one variable in each pot, such as the amount of water given to the plant or the temperature at which it is kept. They could make predictions on how they think each plant will grow and then observe their growth regularly. Comparisons could then be made and conclusions drawn on what plants need to grow.

Alternatively, students could conduct the same experiment described in this clip and remove the leaves from one plant to observe its growth in comparison to another plant of the same type with its leaves still attached.