Soap, one of most important thing in daily life. From kitchen sink to washroom soap is the most common thing to see. For those who use soaps, dishwashers or handwashes bubbles are not so uncommon to them. It is hard to find any kid who doesn’t play with soap bubbles. Now, this playing stuff took attention of scientists.

A team of Scientists from the Imperial College London started examining on the soap bubble, With a very high-speed camera. They zoomed in on the surface of a soap bubble and shoot it until it popped out. The captures footage was amazing, shimmering rainbows were visible in the thicker bubble skin and in the thinnest region while clusters of dark spots appeared.

Those rainbow colors were determined by the thickness of soap film. According to Science News, when light rays pass through the top and bottom surface of the film then the film combines those rays to amplify in a certain wavelength according to thickness. This kind of optical effect is known as constructive interference. Thicker areas of the film reflect the longer wavelengths of colors and thin film layer reflects short wavelengths of colors, this changing of thickness gives a rainbow-like pattern. When a bubble comes into existence, it gets popped after a certain amount of time because the changing pattern of soap film makes the moisture of bubble to evaporate.

As the film gets thinner, the shortest wavelength of visible light pass through it but, after a certain amount of thickness it gets out of the visible light range and dark spots take those place. Physicist Li Shen named this phenomenon as destructive interference which cancels out light reflection off the bubble’s surface. Those dark spots grow and merge with each other. Dr. Shen and his colleagues first reported about their observation on Nov 22 at the American Physical Society’s Division of Fluid Dynamics meeting in Portland, Oregon and it was officially published in the press release of APSphysics .

This effect is known as ‘coarsening effect’. Dr. Shen Said in that conference that, it is the first time the effect was observed in a soap bubble with just a help of dishwasher and camera. However, those bubbles were popped just after the picture was taken.

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