Something Strange Happens to The Temperature Around Freshly Formed Bubbles

In the dishwasher, on the top of your beer, on the crest of waves, in the saliva between your teeth, and in bubble gun toys are just some of the places where bubbles can be found.

The physics of bubbles are important. The film surrounding bubbles was discovered by researchers from the Université Paris-Saclay.

The film can be up to 8C cooler than the environment surrounding it. Changes in temperature can cause the film to thin and evaporate.

Although this effect is often considered in studies devoted to drop evaporation, to the best of our knowledge, the significance of cooling-induced evaporation is not mentioned in the literature on soap films and foams.

To get a closer look at these soap films and foams, the team put together a mixture of washing up liquid, water, and glycerol, with variations in the final substance used to fine- tune the lifetime and evaporation rate of the bubbles.

The bubbles were tested in various conditions. The difference between the soap film and the ambient air maxes out at 8C in some cases.

It was already known that soap films lose liquid via evaporation in an attempt to release energy, but it has been assumed that the temperature of these films matched the environment.

The researchers observed that the temperature would first decrease and then increase until it reached the ambient temperature again.

The magnitude of the cooling effect depends on both the relative humidity and the initial glycerol concentration.

In industrial processes where bubbles are important, this research could be useful. The outside world's temperature will affect those calculations.

The researchers say that the surface tension of soap films is one of the properties that is likely to be influenced by the temperature gap that they've found.

This is the first study of its kind, though, and a lot more research is needed before scientists can say how the temperature of the film that makes up a bubble can be impacted.

The model proposed by the researchers describes the temperature drop of soap films after they are formed.

The dynamics of soap films need to be carefully considered in future studies.

The research has appeared in a journal.