They trapped a cloud of around 100,000 rubidium atoms in a magnetic field inside a vacuum chamber and tossed the chamber down a drop tower to let the atoms float uninhibited by gravity and slow their molecular motion. These days, nanokelvin (nK = 10^−9 K) temperatures are reasonably easy to achieve, and everyone's now working on picokelvins (pK = 10^−12 K),' said David McKee, a professor of physics at Missouri Southern State University.Īs of this writing, the record-low temperature was achieved in 2021 by a team at the Center for Applied Space Technology and Microgravity (ZARM) at the University of Bremen in Germany. 'There's a field of ultra-low-temperature research, and every time you turn around there's a new record low. We can extrapolate from experimental data that the entropy of a perfect crystal reaches zero at absolute zero, but we can never demonstrate this empirically.

Implications of the third lawīecause a temperature of absolute zero is physically unattainable, the third law may be restated to apply to the real world as: The entropy of a perfect crystal approaches zero as its temperature approaches absolute zero. Such calculations cannot be done using the Celsius or Fahrenheit scales, i.e., 100 C is not twice as hot as 50 C, nor is 100 F twice as hot as 50 F. A sample of confined gas at 100 K also contains twice as much thermal energy, and it has twice the pressure as it would have at 50 K. For example, 100 K actually is twice as hot as 50 K, according to the University of Texas. Temperature increments in the Kelvin scale are the same size as in the Celsius scale, but because it starts at absolute zero, rather than the freezing point of water, it can be used directly in mathematical calculations, particularly in multiplication and division. The temperature unit bearing his name, the kelvin (K), is the one most commonly used by scientists worldwide. The person most associated with the concept of absolute zero is William Thomson, 1st Baron Kelvin. (Image credit: Bettmann / Contributor via Getty Images)

The Kelvin temperature scaleĪ photo of William Thomson, 1st Baron Kelvin. Using this technique, Lambert calculated absolute zero to be minus 270 degrees Celsius (minus 454 Fahrenheit), which was remarkably close to the modern accepted value of minus 273.15 C (minus 459.67 F), according to Britannica. It should be rather simple, then, to extend the line backward and read the temperature where the line crosses the x axis, i.e., where y = 0, indicating zero pressure. If one were to plot the temperature-pressure relationship of the gas on a graph with temperature on the x (horizontal) axis and pressure on the y (vertical) axis, the points would form an upward-sloping straight line, indicating a linear relationship between temperature and pressure, according to Florida State University. It was reasonable for Lambert to assume that if the temperature of the gas could be brought to absolute zero, the motion of the gas molecules could be brought to a complete stop so they could no longer exert any pressure on the walls of the chamber. The hotter it gets, the faster the molecules move, and the greater the pressure they exert when they collide with the walls of the container. This is because the temperature of a gas is a measure of the average speed of the molecules in the gas. When a gas is heated in a confined space, its pressure increases. Lambert based this calculation on the linear relationship between the pressure and temperature of a gas. In her book, 'The Story of Physics' (Arcturus, 2012), Anne Rooney wrote, 'The third law of thermodynamics requires the concept of a minimum temperature below which no temperature can ever fall - known as absolute zero.' She continued, 'Robert Boyle first discussed the concept of a minimum possible temperature in 1665, in ' New Experiments and Observations Touching Cold', in which he referred to the idea as primum frigidum.'Ībsolute zero is believed to have been first calculated with reasonable precision in 1779 by Johann Heinrich Lambert, according to Jaime Wisniak of Ben-Gurion University of the Negev in Israel.

Absolute entropy solid ice