About Kelvin
Kelvin is an absolute temperature measurement defined in the International System of Units (SI). It is named after the Scottish physicist William Thomson (Lord Kelvin) who studied the field of thermodynamics. The Kelvin scale is based on absolute zero; the point at which all molecular motion ceases.
Unlike most other temperature scales, Kelvin does not have degrees as it is not a relative scale. The Kelvin scale is often used in physics, chemistry, and cosmology.
One advantage of Kelvin is that it does not have negative values making some calculations easier. This is useful in science calculations involving gases as it relates to the kinetic energy of molecules.
About Rømer
Ole Rømer made significant contributions to the field of temperature measurement.
He was a Danish astronomer known for his work in the late 17th century. The Rømer scale (also known as the Danish scale) was based on the freezing and boiling points of water as many temperature scales are. Rømer's scale used the freezing and boiling reference points as 0 degrees and 60 degrees respectively. While the Rømer scale is no longer used it played a role as an early precursor to the Celsius scale.