Complete combustion experiment. Apparatus used to demonstrate how water and carbon dioxide is produced during complete combustion. Methane gas is burnt (combusted) by the Bunsen burner (right) and the gases produced are collected by the funnel and pass along the tubing (red). The water condenses in a U-tube surrounded by ice (centre), whilst the carbon dioxide is passed through a test tube of limewater (calcium hydroxide solution, left), turning it milky.