CHILLY BUB­BLES

Focus-Science and Technology - - Physics -

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.

En­joy Enjo a glass of bbub­bly and mar­vel mar at the physics phy of pressure pres

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