Nano-science might be too small to see, but in this short clip we demonstrate the physics behind an opal's shimmering colour - on a truly human scale!
Opalescence arises when waves of light reflect from microscopic silica spheres inside the opal gemstone. These tiny spheres are packed tightly together into a very regular, ordered arrangement, so that the light that bounces off them interferes to give a bright reflection of a particular colour.
In the demo, our bodies deflect sound waves in a similar way. The deflected sound is picked up by a microphone, and you can watch how the volume changes on the laptop display (centre front). When we stand in a periodic arrangement, the noise is deafening, but just see how the volume signal drops dramatically as soon as we slip out of order!