I was at Theatre Junction Grand last weekend for an awards ceremony and noticed some low-hanging light bulbs in the reception area as a design feature. An incandescent light bulb produces ‘light’ via a filament wire that uses an electric current to heat it to a very high temperature, at which point the filament begins to glow. The filament is connected to contact wires and a base. The bulb itself is filled with an inert gas (like argon), or were evacuated in early designs in order to protect the hot filament from oxidation. However, less than 5% of the energy is converted into actual visible light (the rest is heat!), making incandescent bulbs extremely inefficient. To increase the efficiency, the filament is usually coiled to maximize the amount of material that can be used in a small volume. Original light bulbs used a carbon filament, but a progression in the technology led to the use of a tungsten filament that lasts longer and tends to be brighter. (Note that light made without heat is luminescent, whereas light generated via heat is incandescent.) It is much more common now to see fluorescent lamps.
Reproductions of Edison’s original exposed filament bulbs seem to be a common design trend because of the warm glow and atmosphere they create. It is a throwback to vintage with a whole lot of science!