The Kelvin Scale

In physics, zero on the Kelvin scale is also known by which term?

And the answer: absolute zero.

Photo courtesy: Andrew Johnson / Getty Images.

The Kelvin temperature scale begins at zero, known as absolute zero, which is the lowest temperature that is theoretically possible. It's equivalent to –273.15 degrees Celsius.

In 1848, William Thomson, also known as Lord Kelvin, began to theorize on the freezing point of molecules. Following a discovery regarding the relationship between the volume and the temperature of gasses, Kelvin investigated the notion that the volume of a gas should become zero at a temperature of minus 273.15 C.

As a result, Kelvin’s studies gave way to what he termed "absolute zero," or the point where molecules stopped moving. Also referred to as "infinite cold," this threshold is not technically possible to reach. Scientists have recently used lasers to draw extremely close to Kelvin’s fated zero, yet it stands as more of a point of reference for temperature increments equivalent to Celsius.

Because absolute zero does not include negative values, it is a helpful scale for reading the low temperatures of elements such as helium and nitrogen in liquid forms. It is also helpful for calculating differences in temperature across disciplines of physics, chemistry and biology.

Fun fact!

The closer scientists draw to absolute zero, the wackier the properties of the element become. At low enough temperatures, liquid helium can become a sort of superfluid, or a liquid able to flow without any resistance of friction. This enables the substance to do things such as spontaneously flow upward or seep through molecule-sized cracks. Considering the temperatures to unlock these properties are colder than that of outer space, no wonder absolute zero is out of this world!

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