Question

why do we have three types of measures units of temperature​

Answer 1

Answer:

There isn’t really a need per se for three scales. One scale would suffice. It’s more of a historical reason for there being three scales. Farenheit and Celsius (both inventors and scientists) invented their own thermometers that used different scales, which they themselves devised.

Both scales were invented around the same time in history (~1720). Following scientific conventions (in this case meetings between scientists to debate and figure out standards by which they should work to), the Celsius scale was adopted most widely around the global scientific community, except the USA, where the Farenheit scale was adopted.

The Kelvin scale was invented and introduced later on (1848), following the discovery of an “absolute zero” temperature, at which molecules stop moving and there is no “heat” energy left in them to be extracted. This state is reflected on the Kelvin scale as “0”.

The Kelvin scale is now mostly used in the scientific community (some equations involving temperature may require a temperature input in terms of Kelvin). However, the Farenheit and Celsius scales have become well established and known scales of temperature throughout society. They had become, and still are, “common” knowledge. For this reason they are still used today for everyday things (such as cooking, meteorology etc.)