The primary gas commonly used in light bulbs is argon, an inert noble gas. Argon is preferred because it does not react with the filament, prolonging the bulb's lifespan and preventing the filament from oxidizing and failing. Incandescent light bulbs utilize a filament made of tungsten, which emits light when electrified. The presence of argon inside the bulb reduces the heat produced and improves efficiency. Modern lighting technologies, such as fluorescent and LED bulbs, use different methods and gases, but argon remains a fundamental component in traditional incandescent bulbs, contributing to their effectiveness and longevity in providing illumination.