Units of temperature

Units of temperature

The units of temperature are on today’s menu. This is an important unit for heat transfer calculations. Used units of temperature include: degrees Celsius, degrees Fahrenheit (in US) and Kelvin (in Science).

These temperature scales share two features:

  • Each scale uses a reference point as zero degrees
  • And each scale changes with a certain size

The following graph displays both degrees Celsius and degrees Fahrenheit in terms of the Kelvin temperature scale. Note both units differ in their zero point and slope.

Units of temperature scales

Units of temperature: Celsius

The Celsius temperature scale uses the freezing point of water, namely zero degrees Celsius, as a reference point. Furthermore, hundred degrees Celsius corresponds with the boiling temperature of water. These temperature scales are always defined at standard atmospheric pressure, because the boiling point of a compound changes with pressure.

The following formula displays units conversion from degrees Fahrenheit and Kelvin to Celsius temperature unit.

Celsius temperature scale

Units of temperature: Fahrenheit

The Fahrenheit units of temperature defines the freezing point of water at 32 degrees Fahrenheit. In addition, the boiling point of water is defined at a temperature of 212 degrees Fahrenheit (standard atmospheric pressure).

The following formula displays temperature unit conversion to degrees Fahrenheit.

Fahrenheit temperature scale

Units of temperature: Kelvin

We finally discuss the Kelvin units of temperature, mainly used in scientific calculations.The zero degrees of Kelvin point describes the lowest possible temperature. All molecules will show minimal movement at this temperature. And the second reference point corresponds with the triple point of water, namely 273,15 K. This triple point describes the conditions where the gas, liquid and solid form of a component are in equilibrium.

Kelvin temperature scaleTemperature differences

Above conversions can be simplified for calculations with energy differences. The Kelvin and degrees Celsius temperature  differences are actually equal to each other. Furthermore, energy difference in Fahrenheit is converted to difference in Kelvin by dividing the Fahrenheit difference with 1,8.

I’m confident above conversions prepares you for the usages of the units of temperature of degrees Celsius, degrees Fahrenheit and Kelvin.


@ Engineerings fundamentals

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