The degree Fahrenheit (° F) is a unit of temperature proposed by Gabriel Fahrenheit in 1724. The degree Fahrenheit is not a unit of the International System of Units.
On the Fahrenheit scale, the state change temperatures of the water are as follows:
- Melting point of water is 32 degrees F.
- Boiling point of water is 212 degrees F.
A difference of 1.8ºF is equivalent to that of 1 degree Celsius. Fahrenheit set the temperature to zero (0 ° F), to the freezing point of a 50% mixture of salt (ammonium chloride) and ice, and at 96 ° F, he took the blood temperature (he used that of the horses ).
The figure 96 may seem like a strange measure, but in principle the scale only contained twelve equal subdivisions, he himself divided each division into eight more, finally obtaining 96 divisions in his scale.
The conversion formulas to degrees Celsius and kelvins are:
°F = °C⋅ (9/5) +32
°C = (°F -32) ⋅ 5/9
°F = K ⋅ (9/5) -459,67
k = (°F +459,67) ⋅ 5/9
In which countries is the Fahrenheit scale used?
The Fahrenheit scale is officially used in five countries:
- The Bahamas.
- The Cayman Islands.
- The United States of America.
Furthermore, this unit is also unofficially used by the older generation in the UK, Australia, South Africa, Canada, Ireland, India and Jamaica. The reason is that this scale has also been used in these countries in the past. In other countries, the temperature is expressed in degrees Celsius that was created 20 years later.
This scale is currently confined in Anglo-Saxon countries, especially the United States. The other Anglo-Saxon countries, however, are adapting to degrees Celsius, since since the 1960s, some governments have pursued policies with a tendency to adopt the International System and the use of ºF for temperature measurement has been displaced .
The Fahrenheit scale, has the absolute zero located at -459.67 ° F, to facilitate its scientific use, the Rankine scale was created. The Rankine scale brings 0 from the Fahrenheit scale to absolute zero, similar to what happens between the Kelvin scale and the Celsius scale.
Who Was Daniel Fahrenheit?
Daniel Fahrenheit was a German-born Polish-born physicist, engineer, and glassblower. He is the physicist responsible for creating the scale that bears his name to measure temperature. He is also known for the invention of the alcohol thermometer (1709), the mercury thermometer (1714) and for the development of a scale for measuring temperatures.
He is a pioneer of exact thermometry, who helped lay the foundation for the era of precision thermometry by inventing the glass tube mercury thermometer and the Fahrenheit scale. Fahrenheit's inventions marked the beginning of the first revolution in the history of thermometry. From the early 1710s to the dawn of the electronic age, glass mercury thermometers were among the most reliable and accurate thermometers ever invented.
How was the Fahrenheit degree invented?
Fahrenheit himself wrote in 1724 that, on his scale, 0º corresponded to the temperature of a mixture of ice, salt and water, while 100º was the body temperature of the human being. We can see that the temperature in these two environments is not completely accurate, so the Fahrenheit scale is considered to be quite arbitrary.
It is not known exactly how it was designed since the German physicist and engineer kept his formulas secret.
Fahrenheit was based on the Rømer scale, proposed by the Danish astronomer Ole Christensen Rømer in 1701. According to this scale, 0 ° was the freezing temperature of the brine and 60 ° the boiling point of water. The problem was that other important points, such as body temperature, were converted into fractional numbers, which seemed rather inelegant to him. Fahrenheit decided to adjust the Rømer scale so that the water would freeze at 8º and the human body temperature would be 24º.
The first Fahrenheit thermometers used this scale, but at some point he decided to multiply the number of divisions by 4, resulting in the current Fahrenheit scale where the freezing point of water is 32ºF and the body temperature is 96ºF. It is not known for sure why he did this, but the fact is that he agrees that one degree Fahrenheit increases the volume of mercury exactly 0.01%.
Who invented the thermometer?
Daniel Gabriel Fahrenheit is also responsible for the invention of the mercury thermometer. Fahrenheit knew that mercury was a better measurement liquid than alcohol used in other thermometers, since it boiled at a much higher temperature (357 ºC versus 78 ºC). His thermometers became the most reliable of the time, and for those achievements he was formally accepted into the Royal Society of London.