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General Science / Re: How Do We Know The Temp Of Absolute Zero If We Can never Reach It ?
« on: Today at 11:12:27 »How Is The Temperature of Absolute Zero Known If We can Never Achieve It ?How was it known to today's precision? I don't know the history of that. The law of gasses gives a good guess.
It says that "the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature" so you grab a bottle, fill it with some gas, seal it, put the bottle in a vacuum, and then measure the temp and pressure. Then do that at other temps. Graph what you get. It should give a pair of straight lines for pressure and temp. Extrapolate the lines down to where the pressure is zero and where the temp line is yields absolute zero, Kelvin.
I say I don't know how because that only gets you an approximation. You cool a gas enough and it suddenly becomes liquid and that has to mess with the pressure curve since it is now (mostly) sitting at the bottom of your bottle and is not so busy pressuring it.