Inert gas asphyxiation lacks oxygen and consists of an asphyxiant gas (one or more of argon, nitrogen or carbon dioxide), causing the animals to lose consciousness. Argon and nitrogen are important components of a gassing process which seem to cause no pain, and for this reason many consider some types of controlled atmosphere killing more humane than other methods of killing. However, "stunning" is often done using carbon dioxide. If carbon dioxide is used, controlled atmosphere killing is not the same as inert gas asphyxia, because carbon dioxide at high concentrations (above 5%) is not biologically inert, but rather is toxic and also
Longest-lasting light bulbs have been so infrequently turned off, this is the precise reason for their longevity. Most of the wear and tear that leads to burnouts in incandescent light bulbs is caused by turning them on and off, not by burning them. Each time the bulb is turned on and off, the filament is heated and cooled. This causes the material of the filament to expand and contract, in turn causing micro stress cracks to develop. The more the light is turned on and off, the larger these cracks grow, until eventually the filament breaks at some point, in non-spectacular fashion, thus