Building with bubbles

Let's discuss one of the more surprising building materials in my study of architects; bubbles.

Bubbles—fragile, ephemeral, soft—provide crucial functionality in the lives of many species, serving as shelter, transportation, hunting tools, and even protection.  From nesting betta fish to bubble-net-weaving humpback whales, the ingenuity and diversity of nature’s architects demonstrate just how versatile bubbles as a building material can be.

Consider the betta fish and the tungara frog.  These animals build bubble nests to first attract a discerning mate while providing a safe haven for their young, reinforcing the delicate bubbles with mucus for added stability.  Violet snails go one step further, secreting bubble rafts from mucus that allow them to float with the currents along the ocean’s surface.  Humpback whales use bubble nets as a hunting strategy, corralling fish into tight clusters for easy capture.  The diving bell spider, which uses silk to reinforce an underwater bubble, creates a portable air pocket (i.e., the diving bell) that allows the spider to breathe and hunt below the surface.  Bubbles can even provide defense: garden snails generate a foam barrier to deter predators.​

These bubble structures are uniquely held together depending on the species and their purpose.  Humpback whale bubble nets, for instance, rely on surface tension to maintain their form.  However, as the bubbles rise and pressure decreases, the bubble increases in volume, the surface tension can't compensate for the larger size, causing the bubbles to fragment into smaller ones, creating a cascading sheet-like wall of tiny bubbles.  Other animals, like betta fish, true bugs, and grey tree frogs, fortify their bubbles with mucus, adding strength and durability.

Bubbles are viscoelastic—they behave both like a solid and a liquid.  This duality offers significant advantages.  As solids, bubbles provide structure, creating barriers that protect the builder or their offspring from external threats.  Their elastic nature allows them to deform under stress and then recover their shape, maintaining their protective function.  Meanwhile, their fluid-like properties make them adaptable and able to conform to various shapes and environments, whether floating on the surface of a pond or clinging to a tree branch.

But for all their versatility, bubbles are fleeting.  They’re fragile, often lasting just long enough to fulfill their purpose before disappearing.  Still, their ephemeral nature doesn’t diminish their importance—it highlights the resourcefulness of the creatures that wield them.  Additionally, there is something to be said for engineering something that is designed to disappear - a design challenge we haven't sufficiently solved for ourselves.

Whether practical or whimsical, I enjoy the thought process of thinking through how we can mimic other non-human builders/architects.   It makes me wish I were a better artist.  I enjoy the vision of a machine producing bubbles to create spherical, artistic structures, reinforced with some medium (perhaps mud, concrete, maybe even ice).  Perhaps bubbles floating to a geodesic frame, attaching via surface tension to create cover, or a soldier using a bubble gun to create a protective, quickly built wall to protect themselves, or may art (for the sake of art).