For Burton, this was also an indication that the thickness of the soap was just a few microns, roughly equivalent to the wavelength of light. This effect is due to interference patterns created when light reflects off the two surfaces of the film.
He was especially intrigued by the shifting rainbow of colors on the bubbles' surface. He saw street performers producing giant bubbles about the diameter of a hula hoop and as long as a car. Wave the wand slowly or blow on it to create giant soap bubbles.īut what about blowing gigantic bubbles or long, thin soap films that can span two stories? Justin Burton, co-author of the latest paper and a physicist at Emory University specializing in fluid dynamics, first got intrigued by the topic at a conference in Barcelona. The water should thicken slightly, like thin soup or unset gelatin.Īdd the Dawn Professional Detergent and stir gently, to avoid causing the mixture to foam.ĭip a giant bubble wand with a fibrous string into the mixture until it is fully immersed and slowly pull the string out.
Let it sit for a bit so the guar hydrates. Mix the guar powder with the alcohol and stir until there are no clumps.Ĭombine the alcohol/guar slurry with the water and mix gently for 10 minutes. Over time, that shape will start to look more like a soccer ball than a perfect sphere as gravity pulls the liquid downward ("coarsening").ĥ0 milliliters of Dawn Professional Detergent (a little over 3 TBSP)Ģ-3 grams of guar powder, a food thickener (about 1/2 heaping TSP)ĥ0 milliliters of rubbing alcohol (a little more than 3 TBSP) Surface tension is why bubbles are round that shape has the least surface area for a given volume, so it requires the least energy to maintain. In the 1800s, Belgian physicist Joseph Plateau outlined four basic laws of surface tension that determine the structure of soapy films. That produces a soap film able to stretch sufficiently thin to make a giant bubble without breaking.īubbles may seem frivolous, but there is some complex underlying physics, and hence their study has long been serious science. Physicists have determined that a key ingredient is mixing in polymers of varying strand lengths, according to a new paper in Physical Review Fluids. But to blow really big, world-record-scale bubbles requires a very precise bubble mixture. Burton Lab/Emory University reader comments 57 withĮverybody loves bubbles, regardless of age-the bigger the better.
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