Rømer scale
Encyclopedia
Rømer is a temperature
scale named after the Danish
astronomer
Ole Christensen Rømer, who proposed it in 1701.
In this scale, the zero was initially set using freezing brine
. The boiling point of water
was defined as 60 degrees. Rømer then saw that the freezing point of pure water was roughly one eighth of the way (about 7.5 degrees) between these two points, so he redefined the lower fixed point to be the freezing point of water at precisely 7.5 degrees. This did not greatly change the scale but made it easier to calibrate by defining it by reference to pure water. Thus the unit
of this scale, a Rømer degree, is 100/52.5 = 40/21 of a kelvin
(or of a Celsius
degree). The symbol is sometimes given as °R, but since that is also sometimes used for the Rankine scale, the other symbol °Rø is to be preferred. The name should not be confused with Réaumur.
The inventor of the Fahrenheit scale Daniel Gabriel Fahrenheit learned of Rømer's work and visited him in 1708; in one of his letters Fahrenheit narrates how he borrowed the idea for the scale from this visit, increasing the number of divisions by a factor of four and eventually establishing what is now known as the Fahrenheit
scale, in 1724.
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
scale named after the Danish
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
Ole Christensen Rømer, who proposed it in 1701.
In this scale, the zero was initially set using freezing brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
. The boiling point of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
was defined as 60 degrees. Rømer then saw that the freezing point of pure water was roughly one eighth of the way (about 7.5 degrees) between these two points, so he redefined the lower fixed point to be the freezing point of water at precisely 7.5 degrees. This did not greatly change the scale but made it easier to calibrate by defining it by reference to pure water. Thus the unit
Units of measurement
A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of...
of this scale, a Rømer degree, is 100/52.5 = 40/21 of a kelvin
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
(or of a Celsius
Celsius
Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
degree). The symbol is sometimes given as °R, but since that is also sometimes used for the Rankine scale, the other symbol °Rø is to be preferred. The name should not be confused with Réaumur.
The inventor of the Fahrenheit scale Daniel Gabriel Fahrenheit learned of Rømer's work and visited him in 1708; in one of his letters Fahrenheit narrates how he borrowed the idea for the scale from this visit, increasing the number of divisions by a factor of four and eventually establishing what is now known as the Fahrenheit
Fahrenheit
Fahrenheit is the temperature scale proposed in 1724 by, and named after, the German physicist Daniel Gabriel Fahrenheit . Within this scale, the freezing of water into ice is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees...
scale, in 1724.