Bubbles aren’t known for their lengthy lifespans, usually only giving a few seconds or minutes of childlike joy before they pop. But a team of French scientists has developed a new way to make longer-lasting bubbles, with the record holder surviving for well over a year.
The physics of soap bubbles, and why they pop, probably aren’t things that many of us have spent much time pondering. Normally, their thin skin is made up of a layer of water sandwiched between two layers of soap molecules, which burst when that water escapes. There are three main ways this can happen – the first and most obvious is when something sharp breaks it. But the water can also evaporate into the air, or drain down through the bottom of the bubble.
But none of those forces are a match for a type of bubble called gas marbles, which are made of a liquid solution with plastic beads in it. When these are inflated, the beads form a much thicker skin, allowing the bubble to be held or rolled around. Gas marbles were only created for the first time in 2015, but just how long they could survive remained untested.
So for the new study, researchers from the University of Lille in France set out to ascertain exactly that. Using a balance and a camera, the team monitored the lifespan of three different types of bubbles – regular old soap bubbles, gas marbles, and gas marbles made with glycerol added to the solution. Glycerol is often added to bubble mix to help them last longer.
The soap bubbles lasted for about a minute before they popped. The water-based gas marbles performed better, with some surviving for up to an hour. But those with glycerol blew the competition out of the water, remaining intact for weeks or months, and one stubborn little bubble lasting an astonishing 465 days.
The team says that the glycerol and the plastic particles work together well to counteract two of the main popping mechanisms. Glycerol absorbs water from the air around the bubble, which counters the evaporation problem. Meanwhile, the plastic shell keeps the water from draining out through the bottom.
The researchers say that the new long-lasting bubbles could be used to make stable foams, or as a way to store gases.
The research was published in the journal Physical Review Fluids.
Source: APS Physics
