CHILLY BUBBLES
If you wanted to chill something down to -60°C, then you’d probably think about buying an expensive freezer, yet this is exactly what happens every time you hear a champagne cork pop. When a compressed gas expands into the atmosphere, it cools (that’s why the spray from an aerosol always feels cold). The greater the ratio of the initial and final pressures, the greater the cooling. The gas in the neck of a chilled bottle of champagne has a pressure of around four atmospheres, which is roughly the same pressure experienced by a scuba diver at a depth of 30m. As the cork flies away and the gas expandsands outwards,outw the temperaturemperature in the bottlebo neck briefly plummets to -60°6C. The cold makes water concondense into droplets, forming fog.