When I lived in the USA I spent my laboratory days in the Celsius-world.
Once I left the laboratory I found myself in the world of Fahrenheit.
The Celsius world was accompanied by his friends called cm, km and kg while Fahrenheit’s friends were inch, miles and pounds.
The laboratory had to follow the standard measurements while the country did not. And I had to learn how to switch!
But how did all this happen? Why do different countries use different measurements?
Daniel Gabriel Fahrenheit
Daniel Gabriel Fahrenheit (1686-1730) developed a scale in 1724 and put 0 °F as the point where a mixture of ice, water and a salt called ‘ammonium chloride’ stabilized. .
For the second point he used a mixture of only ice and water. This is the freezing point at 32 °F
The third point at 96 °F was the human body temperature.
Later the scale was slightly modified by setting the human body temperature to 98 °F and the water boiling point to exactly 212 °F (which is exactly 180 degrees higher than the freezing point of 32°F).
The Fahrenheit scale was the primary temperature standard used in English-speaking countries until the 1960s. Then Celsius replaced Fahrenheit in most countries; the USA being one the exceptions. Scientists use Celsius or Kelvin in all countries. Within the European Union, it is mandatory to use Kelvin or Celsius.
Funny that Germany is using Celsius and not Fahrenheit, even Daniel Gabriel Fahrenheit was German!
Astronomer Anders Celsius (1701–1744) was from Sweden. He set the freezing point of water at 0 °C and the boiling point of water at 100 °C. On his scale, he first put 100 down and 0 up but this was reversed later by other scientists. Since temperature is always depending on pressure (see my post ‘Do you know why you can’t boil an egg on Mount Everest?’ the 0 °C is set at sea level pressure.
That is how Celsius is still taught in school and how it is logic to everyone!
Maybe that is the reason why the scale was changed. To confuse us against common sense. Officially it was changed to make it fit with Kelvin, the standard temperature of the thermodynamic temperature scale. Kelvin sets the absolute Zero at 0 Kelvin and the water’s triple point (=special purified water) at 273.16 K.
And to confuse us all, the Celsius scale is now defined from absolute 0 to water’s triple point as well! This makes a scale from -23.15 °C to 0.01 °C.
But luckily we don’t feel the new definition since temperature measures are now mostly electronically and do not show a scale. At my home however I still have some scales and they are (and will be) from 0 °C – 100 °C!
Now I live in a country that measures officially in Celsius but sells cookers that use Fahrenheit. My car is American and its thermometer uses Fahrenheit while my speed shows me miles as well as kilometers. Funny world, isn’t it? But I am still flexible.
I have an app that converts between Celsius and Fahrenheit as well as Kilograms and Pounds. But I am getting better and know the conversion by heart now e.g. 104 °F in my car means 40 °C and this means a very very hot day!
If you are interested you can calculate according to the following table:
|Fahrenheit||[°F] = [°C] × 9⁄5 + 32||[°C] = ([°F] − 32) × 5⁄9|
|Kelvin||[K] = [°C] + 273.15||[°C] = [K] − 273.15|
Over to you!
What about you? Do you live in Celsius-world or Fahrenheit-world? Do you have to switch between your worlds?