A new video on imgur shows two kids peeking out of a towering "bubble igloo" emerging from a bathtub. The column of bubbles reaches nearly to the ceiling, leaning slightly but not collapsing. "HOW???" asked one commenter, quite reasonably.
The original poster hasn't clarified precisely how they created the tower of bubbles, but you can probably do this at home … if you don't mind a mess. Surfactants — like soap — can easily form stable foams, said Donald Freese, a chemical engineer formerly at W.L. Gore. Foams are gas bubbles dispersed in liquid; no foam is perfectly stable, because bubbles eventually pop and the gas pockets merge, becoming larger and breaking down the overall foam structure. But when soap bubbles are small and there are few disturbances, foams can stick around and stand up against the forces of gravity for a long time, Freese said. [Check Out Amazing GIFs of Chemical Reactions]
"Bubbles do pop, but the rate that they pop can be very slow for some types of surfactants if they are concentrated enough and if the system is free of oily contaminants and any other disrupting forces, such as airflow," Freese said.
Stable foams are frequently used in firefighting, Freese said. They're also used as a drilling fluid in oil wells, according to oil field company Schlumberger; special foams are sometimes added to the well as the drill bit churns through the rock to lubricate it and facilitate the movement of dust and rock chips. Stable foams might even show up in the kitchen, as when beating egg whites into a stiff meringue.
A bubble tower like the one in the imgur video could be made with soapy water (from dish soap or bubble bath) and an air pump to introduce the gas, said Laurent Courbin, a CNRS researcher at the Physics Institute of Rennes at the University of Rennes 1 in France.
"New bubbles would then be created at the level of the liquid surface, while old ones on top of the foam get higher," Courbin told Live Science. A barrier like a shower curtain, pulled away before filming started, might have helped to keep the bubbles corralled.
As for how to churn up enough air to raise bubbles to the ceiling, bathtub jets might do the trick. For the tragically jetless, some companies sell bubble machines for bathtubs. These bubble makers are shaped like mats that go on the bottom of the tub or units that attach to the side, and they generally cost around $100 or less.
Original article on Live Science.