HAND THROUGH FLAT SOAP BUBBLE - David Elfstrom, Toronto, Ontario -- (Winner, 1st prize, Open Category, 2003 Art of Physics Competition / Gagnant, Premier prix, catégorie ouverte, Concours 2003 l’Art de la physique)

A flat bubble is made from a mixture of water, dish detergent, and glycerin by dipping a wire frame into the mixture. The frame with the bubble is held above a dark surface, and a studio flask with a ‘softbox' is aimed at the bubble. The camera is aimed so that the reflection of the flash will be seen over the entire surface of the bubble, and a photograph is taken of that reflection, showing a swirling pattern of colours. Interference between the light waves reflected from the front of the film and the back create a shift in colour. Small variations in thickness of the film show up as different colours. By whetting one's fingers with the solution, it is possible to poke a finger or two through the bubble without breaking it. Oils from the skin cause the fluid to move and swirl in unpredictable ways.