TEMPERATURES SCALES

KELVIN SCALE

Kelvin is a temperature scale designed so that zero degrees K is defined as absolute zero (at absolute zero, a hypothetical temperature, all molecular movement stops - all actual temperatures are above absolute zero) and the size of one unit is the same as the size of one degree Celsius. Water freezes at 273.16K; water boils at 373.16K. [ K = C + 273.16°, F = (9/5)C + 32°].

This temperature scale was designed by Lord Kelvin (William Thomson, 1824-1907). Kelvin was a British inventor and scientist (he was born in Belfast, Northern Ireland in 1824). In addition to his work on temperature, Kelvin invented over 50 devices (including the mirror galvanometer, which detects and measures weak electric fields), discovered the second law of thermodynamics (the amount of usable energy in the universe is decreasing), and wrote hundreds of scientific papers.

FORMULAS

• Celsius to kelvin K = C + 273.15
• Fahrenheit to kelvin K = ( F + 459.67) / 1.8
• Rankine to kelvin K = Ra / 1.8
• kelvin to Celsius C = K - 273.15
• kelvin to Fahrenheit F = K × 1.8 - 459.67

FAHRENHEIT SCALE

Fahrenheit temperature scale (fârˈənhĪtˌ) [key], temperature scale in which the temperature difference between two reference temperatures, the melting and boiling points of water, is divided into 180 equal intervals called degrees. The freezing point is taken as 32°F and the boiling point as 212°F.

The scale was established by the German-Dutch physicist Gabriel Daniel Fahrenheit in 1724. William John Macquorn Rankine used it as the basis of his absolute temperature scale, now called the Rankine temperature scale, in 1859.

RANKINE SCALE

Rankine scale absolute scale of temperature in which the unit of temperature is equal to that on the Fahrenheit scale and the zero value of temperature is equal to -459.67°F.

the rankine scale named after the Glasgow University engineer and physicist William John Macquorn Rankine, who proposed it in 1859.

FORMULAS

• Celsius [°C] = ([°R] − 491.67) × 5⁄9 / [°R] = ([°C] + 273.15) × 9⁄5
• Fahrenheit [°F] = [°R] − 459.67 / [°R] = [°F] + 459.67
• Kelvin [K] = [°R] × 5⁄9 / [°R] = [K] × 9⁄5

CELSIUS SCALE

The Celsius scale is a scale of temperature in which 0° represents the melting point of ice and 100° represents the boiling point of water.

In 1742, Swedish astronomer, Anders Celsius invented the Celsius temperature scale, which was named after the inventor.