Gases in the Air – Science Presenta on It’s hard to decide which of the ‘Gases in the Air’ is the most interes ng. Nitrogen, extremely stable in its molecular form becomes explosive when combined in compounds like TNT and nitro-glycerine. This property is exploited in car air bags when we sit just behind a car- tridge of explosive, toxic and lifesaving sodium azide. Oxygen is contender for ‘most interes ng gas. It can be made by the spectacular elephant’s toothpaste reac on, it supports combus on and can create explosive mixtures when combined in the right quan es with other compounds and ele- ments. This was demonstrated in the presenta on when volunteers red explosive gas cannons at Queen Elizabeth I! Carbon dioxide gets bad press as a ‘Greenhouse’ gas but gives life to plants via photosynthesis and ul mately creates our food. In the ‘Gases in the Air’ talk on Wednesday 13th December, the proper es of gases were inves gat- ed, the pressure they exert was demonstrated and in turn they were burnt, exploded and squeezed. A thorough inves ga on of this topic, with lots of audience par cipa on may not have revealed which ‘Gas in the Air’ is the most interes ng but entertained the audience and had fun trying to nd out.