Why do bananas fluoresce? An unexpected view of chlorophyll

As a banana ages, black spots appear on the skin. Shine ultraviolet light on them, and you will see an amazing fluorescent blue ring around each black spot. This is produced as the chlorophyll in the banana skin is broken down.

This makes a fun and thought-provoking lesson starter. Students can be challenged to hypothesise about what they are seeing and why. Do they think that there are adaptive advantages for the plant?

Download the resource for full instructions on how to carry out the activity and the scientific research on the topic.

This activity was suggested by teacher Beverley Goodger, and funded by a SAPS Associate Award.