The physics of soap bubbles represents a fascinating intersection of surface chemistry, fluid dynamics, thin film interference, and thermodynamics, with these seemingly simple structures embodying complex physical principles that have captivated scientists from Sir Isaac Newton to modern researchers in soft matter physics. A soap bubble essentially consists of a thin spherical shell of soapy water enclosing a volume of air, yet this basic structure exhibits remarkable properties that illuminate fundamental concepts in minimal surfaces, molecular interactions, and the delicate balance of forces that govern ephemeral systems. At the molecular level, soap bubbles form because of the amphiphilic nature of soap molecules—each consisting of a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail—which assemble at the air-water interface with their hydrophilic heads oriented toward the water and their hydrophobic tails projecting away from it. This molecular arrangement creates a soap film with a three-layer structure: two molecular layers of soap with water molecules sandwiched between them, typically ranging from 10 nanometers to several micrometers in thickness depending on age and environmental conditions. The characteristic spherical shape of a soap bubble emerges from the principle of minimal surface energy, as surface tension forces the enclosed air to adopt the geometric form that minimizes surface area for a given volume—a perfect sphere. Surface tension, arising from the cohesive forces between liquid molecules, creates an inward pressure that compresses the air within the bubble, establishing a pressure differential between the inside and outside governed by the Young-Laplace equation: ΔP = 4γ/r, where ΔP represents the pressure difference, γ the surface tension, and r the radius of the bubble. This equation reveals the inverse relationship between bubble size and internal pressure, with smaller bubbles experiencing significantly higher internal pressure than larger ones, which explains why smaller bubbles tend to merge into larger ones when bubbles of different sizes are connected. The colorful iridescence displayed by soap bubbles results from thin-film interference, where light waves reflecting from the outer and inner surfaces of the bubble wall interfere constructively or destructively depending on the film thickness and the wavelength of light. As white light contains all visible wavelengths, different colors appear at various points on the bubble where the film thickness causes specific wavelengths to experience constructive interference while others cancel out. The constantly shifting colors observed in soap bubbles reveal the dynamic nature of the film, with gravity causing liquid to drain downward, making the top thinner and the bottom thicker over time. This drainage process represents one of the primary mechanisms leading to bubble destabilization and eventual rupture, as the film at the top eventually becomes too thin to maintain structural integrity. The evaporation of water from the bubble surface accelerates this thinning process, with evaporation rates depending on ambient temperature, humidity, and air movement. The lifespan of a soap bubble involves a complex interplay of stabilizing and destabilizing forces. Surfactants in soap reduce water's surface tension from approximately 72 mN/m to around 25-30 mN/m, making bubble formation possible with reasonable energy input. The Marangoni effect—where surface tension gradients cause liquid to flow from regions of lower surface tension to regions of higher surface tension—helps stabilize soap films by counteracting local thinning. When a region of the film becomes thinner, the concentration of surfactant molecules temporarily decreases in that area, increasing local surface tension and drawing surrounding liquid into the thinned region through Marangoni flow. This self-healing mechanism explains why pure water bubbles are virtually impossible to maintain, as they lack the surfactant molecules necessary for this stabilizing effect. Despite these stabilizing mechanisms, soap bubbles inevitably pop, with rupture typically initiated by one of several mechanisms. Evaporation progressively thins the water layer until reaching a critical thickness—approximately 10 nanometers—at which van der Waals forces between the inner and outer surfactant layers overcome the repulsive forces keeping them apart, causing film collapse. Physical disturbances such as air currents, contact with solid objects, or vibrations can provide sufficient energy to overcome the film's elastic resistance and trigger rupture. Contamination from airborne particles or oils from skin contact can disrupt the surfactant layer's integrity by creating areas of locally reduced surface tension. Temperature gradients across the bubble surface generate Marangoni flows that can destabilize the film structure. Once rupture initiates at any point, surface tension causes the film to contract away from the hole at remarkable speeds—approximately 10 meters per second—causing the characteristic rapid disappearance of the entire bubble structure. The rupture process itself reveals fascinating fluid dynamics, with high-speed photography showing the formation of smaller daughter bubbles and complex ripple patterns as the film disintegrates. The bursting of a soap bubble releases a surprising number of tiny droplets—often thousands—that can remain suspended in air for extended periods, a phenomenon with implications ranging from aerosol studies to disease transmission. Environmental factors dramatically influence bubble longevity and behavior. Humidity plays a critical role, with higher humidity levels slowing evaporation and extending bubble lifespan—in extremely humid environments, bubbles can persist for hours or even days with appropriate surfactant formulations. Temperature affects surface tension, with lower temperatures generally reducing evaporation rates while increasing surface tension, which can extend bubble duration but may also make initial formation more difficult. Air quality impacts bubble stability, as airborne contaminants, particularly hydrophobic particles, can penetrate and disrupt the film structure. Modern soap bubble formulations often include various additives to enhance stability and performance. Glycerin or other humectants reduce evaporation rates by attracting and retaining water molecules in the film. Polymers increase film elasticity and resistance to rupture by forming cross-linked networks within the liquid layer. pH buffers maintain optimal conditions for surfactant effectiveness, as most surfactants perform best within specific pH ranges. Water-soluble polymers like polyethylene oxide increase solution viscosity, slowing drainage and enhancing structural integrity. These scientific principles underlying soap bubbles have inspired numerous practical applications across diverse fields. In physics education, soap films provide vivid demonstrations of minimal surfaces, with wire frames dipped in soap solution forming complex mathematical surfaces that minimize area under given boundary conditions. Architectural and engineering applications draw on bubble principles for designing efficient structures that optimize material usage while maintaining strength. Medical researchers use bubble behavior to develop improved drug delivery systems and understand cell membrane dynamics. Computer graphics algorithms mimic soap film behavior to generate realistic animations of fluid surfaces. The mathematics of soap bubbles has spawned entire subfields in differential geometry, with the study of minimal surfaces yielding insights applicable to problems in physics, biology, and materials science. The seemingly simple question of why soap bubbles pop thus opens a window into complex interdisciplinary science, where molecular interactions, fluid dynamics, optics, and geometry converge in these ephemeral spheres that continue to inspire both scientific investigation and childlike wonder. From Plateau's early experimental work on minimal surfaces to contemporary research using sophisticated high-speed imaging and computational modeling, soap bubbles remain valuable systems for exploring fundamental physical principles and developing innovative applications in science, engineering, and education.