Boblerne

Boblerne is the Danish term for bubbles, referring to gas-filled spheres that form in liquids or foams. They range in size from microscopic to visible and are bounded by a thin liquid–gas interface that is stabilized by surface tension. The gas inside is typically at near-ambient pressure, while the surrounding liquid is denser, giving the bubble buoyancy that causes it to rise.

Bubbles form by nucleation at impurities, interfaces, or dissolved gas pockets. They can grow or shrink as gas diffuses into or out of the bubble, a process influenced by temperature, pressure, and the presence of surface-active substances (surfactants). The shape of a bubble is roughly spherical at small sizes but becomes oblate with increasing size or under external flow. Bubbles may coalesce to form larger bubbles or split into smaller ones; dissolution can eliminate bubbles if the liquid is undersaturated with the gas.

Bubbles play a central role in many natural and industrial processes. In beverages, carbonation creates boblerne that give fizz and mouthfeel. In water treatment and chemical reactors, bubbles promote gas transfer and mixing. In medicine, microbubbles are used as contrast agents for ultrasound imaging and are investigated for drug delivery. Foams and cavitation are related phenomena in which bubbles are key components.

See also: bubble dynamics, surface tension, cavitation, foam.