How does the whoosh bottle work?

A whoosh bottle demonstrates the principles of combustion and gas expansion. It typically consists of a plastic bottle partially filled with a flammable liquid (like lighter fluid) and air. When the bottle is shaken, the liquid vaporizes and mixes with the air, creating a combustible mixture. Igniting this mixture causes a rapid expansion of gases, resulting in a loud "whoosh" sound as the bottle expels the hot gases and creates a small flame at the opening.