The barrel on a Bunsen burner is the metal tube that is screwed onto the burner’s base. It contains the air intake openings that let air into the burner when uncovered and stop the entry of air when shut. The barrel is about 5 inches long.
A Bunsen burner is a common piece of laboratory equipment that produces a single open-gas flame that can be used for various purposes, including heating, sterilization and combustion. The gas can either be natural gas, mainly methane, or liquefied petroleum gas, such as propane, butane or a combination of the two. Upon connecting to a source of fuel, the Bunsen burner can be ignited with a spark. Incoming gas mixes with oxygen to produce a blue flame that comes out of the barrel.
The volume of the gas flow can be changed by adjusting the gas valve. The more oxygen that is present, the more intense and blue the flame will be. Low amounts of oxygen cause a weaker yellow flame to appear. The blue flame is hotter and more controlled than the oxygen-deprived flame. The air intake openings are strategically located at the bottom of the barrel, and they are deliberately placed there so air can enter.