![]() Nowadays, we know that gasses do not shrink to zero volume when cooled to absolute zero, because they condense into liquids at higher temperatures. ![]() This temperature became known as absolute zero, and is today the zero for the Kelvin and Rankine temperature scales. Scientists noticed that, for all gasses, the temperature at which the graph said they would reach zero volume was about -273 Celsius (about -460 Fahrenheit). If you extend this line to low enough temperatures, it will eventually hit zero volume. (This assumes that you keep the pressure constant.) The lower the temperature, the smaller the volume. The graph of volume vs temperature for a sample of gas forms a straight line. They measured as best they could over the temperature range that they could reach. How much would it shrink? When scientists first began studying the behavior of of heated and cooled gasses, they didn't have our modern cooling methods. Suppose we took a certain amount of air and cooled it as much as we could. Air sinks when it cools because it contracts, so it's more dense than the warmer air around it. It has bouyancy, just like a piece of wood in a pond, which floats because it's less dense than the water. Air rises when it's heated because it expands, so it's less dense than the cooler air around it. We know that hot air rises and cold air falls. The first clue to the existence of absolute zero came from the expansion and contraction of gasses. So if we can never get there, how do we know it's really there? In fact, it's so low that we can never quite reach it, although research teams have come within a fraction of a degree. Our JavaScript temperature converter can give you other temperature comparisons.Ībsolute zero, according to current scientific thought, is the lowest temperature that could ever be. For other comparisons, see the table below. Here's one example of temperature comparisons: 68 Fahrenheit is the same as 20 Celsius, 293.15 Kelvin, and 527.67 Rankine. To convert from Kelvin to Rankine, multiply the Kelvin temperature by 9/5. To convert from Fahrenheit to Rankine, add 459.67 to the Fahrenheit reading. The Rankine temperature scale uses the same size degree as Fahrenheit, but has its zero set to absolute zero. ![]() To convert from Celsius to Kelvin, add 273.15 to the Celsius reading. The Kelvin temperature scale uses the same size degree as Celsius, but has its zero set to absolute zero. According to theory, we never will.) Absolute zero is at -273.15 Celsius, or -459.67 Fahrenheit. (People have gotten close to absolute zero, but have never reached it. There are also temperature scales in which zero is absolute zero, the lowest possible temperature. To convert between Fahrenheit and Celsius use this formula:įahrenheit Temperature = (Celsius Temperature)x(9/5) + 32 In this scale, water freezes at 0 degrees and boils at 100 degrees. At high altitudes, water boils at a lower temperature, as anyone who cooks in the mountains knows.)Īnother common scale is the Celsius (also called Centigrade) scale. (This only holds strictly when atmospheric pressure equals the average sea level pressure. In this scale, water freezes at 32 degrees and boils at 212 degrees. ![]() The most commonly used temperature scale in the US today is the Fahrenheit scale, abbreviated F. Temperature Scales and Absolute Zero Four Temperature Scales
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