Dragonfly Colours: Thin-Film Interference

This demonstration uses a bubble and LED light to illustrate the concept of thin-film interference. It centres a discussion on thin-film interference in dragonflies and asks participants to consider where they see reflection and refraction in their lives. As an extension, participants may find a natural object with structural colouration, such as a bird feather, butterfly wing, or beetle exoskeleton, and drop some rubbing alcohol on top to see if there are colour changes. 

This demo pairs well with Dragonfly Flight: Waves and Wing Movement, Dragonfly Sight: UV Light and Electromagnetic Waves, Transverse and Longitudinal Waves, and Reflection & Refraction. This demo is part of the 2024 SOCK, The Wonders of the Dragonfly.