Now that most of the world’s major problems have been resolved, science is turning its attention to the less pressing issues plaguing humanity, including how to mix up the perfect soapy solution for making gigantic bubbles that don’t immediately pop.
Scientists have actually been interested in bubbles dating back to the 1800s, and why shouldn’t they be? It seems completely illogical that a thin sphere of soapy liquid could hold itself together long enough to float through the air. As fascinating as they are to a four-year-old watching them come shooting out of a wand, bubbles provide just as much intrigue for chemistry researchers or physicists studying fluid dynamics.
Back in 2016, researchers from the French National Centre for Scientific Research and the University of Rennes unlocked the secrets of how to blow the perfect bubble, including determining what the ideal speed, shape, and size of the air blast needed to generate bubbles of various sizes. That was followed by research in 2018 that concluded the ideal shape and size of a wand for creating the maximum number of stable bubbles was a circle 1.5-inches in size. Two years later, physicists from Emory University have published a paper outlining their new research into how to mix up the best possible soapy solution for creating gigantic bubbles.
What’s most surprising about the research’s conclusions is that, over the years, bubble enthusiasts (yes, that’s a thing!) had already more or less figured out the key ingredients for giant bubbles through trial and error. The researchers gathered recipes from the Soap Bubble Wiki (yes, it’s also a thing!) and rigorously tested the results in their lab, which included high-speed recordings of bubbles popping which allowed them to measure the speed and patterns of disintegration, and how that changed as recipes were adjusted.
The most popular bubble soap recipes on the wiki included the addition of polymers (long chains of molecules) in the form of a food thickening additive known as guar, or polyethylene glycol which is often used in laxatives. When mixed these polymers become entangled creating longer and stronger chains that can be stretched without instantly tearing, producing bubbles that last longer and can be filled to gigantic proportions. The researchers also found that varying the lengths of the polymer chains increased the proclivity of them getting tangled up with each other, which helps ensure that every batch mixed up is able to reliably produce the desired oversized bubbles.
So what was the final recipe they landed on? Grab your measuring cups because precision is the key. Start by adding a heaping half-teaspoon of guar powder to three tablespoons of rubbing alcohol and mix until all the clumps are gone. Add that mixture to two pints of water and gently mix for about 10 minutes, and then let the mixture sit for a few additional minutes which gives the guar time to absorb water. Gently stirring the mixture again you should find it’s become slightly thickened. Stir in a half-teaspoon of baking powder at that point, add three tablespoons of Dawn Professional Detergent, and then do one last stir but gently to ensure no foam is created.
The researchers also suggest using fibrous string or rope for the bubble wand which ensures the soap mixture will be easily absorbed creating an unbroken connection between the thin film and the rope, further increasing the chances of making giant bubbles without them popping too soon. Armed with this knowledge (plus a vest and a beret) you’ve got everything you need to be the star of your city’s next Busker Festival once the summer months arrive.