Square bubble

No matter how many times you blow a bubble, it always ends up round. This is because the molecules in the bubble mixture pull on each other, which means that you end up with a shape that has the smallest amount of surface (a sphere). In this experiment a bubble is surrounded by other bubbles, these side bubbles push against the centre bubble, squishing and squashing until it has corners and sides and looks like a cube.

Thin-film interference occurs when incident light waves reflected by the upper and lower boundaries of a thin film interfere with one another to form a new wave. The iridescence of a soap bubble stems from light striking the bubble from varied angles. The path length varies with the angle of incident light, giving varying path differences for the internally and externally reflected rays at different points on the bubble. This means that, even if the soap film is of uniform thickness, different colours can be seen.