Rankine to Newton
°R
N
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
| No conversion history to show. | ||
Quick Reference Table (Rankine to Newton)
| Rankine (°R) | Newton (N) |
|---|---|
| 0 | -90.1395 |
| 459.67 | -5.8666666666666666666674 |
| 491.67 | 0 |
| 527.67 | 6.6 |
| 558.27 | 12.21 |
| 671.67 | 33 |
About Rankine (°R)
Rankine (°R) is an absolute temperature scale that uses Fahrenheit-sized degrees. Like the kelvin it starts at absolute zero (0°R), but its degree intervals match Fahrenheit rather than Celsius. This makes it useful in US customary engineering thermodynamics — particularly older American aerospace, HVAC, and mechanical engineering literature — where Fahrenheit-based calculations must account for absolute temperature. Water freezes at 491.67°R, boils at 671.67°R, and body temperature is 558.27°R. The Rankine scale is rarely used today outside legacy US engineering calculations; SI units with kelvin have largely replaced it internationally and increasingly within the US engineering community as well.
Jet engine combustion temperatures around 2,500°F (1,371°C) equal approximately 2,960°R in thermodynamic calculations. Cryogenic oxygen (−183°C) is about 163°R.
Etymology: Named after Scottish engineer William John Macquorn Rankine (1820–1872), who proposed the scale in 1859. Rankine made major contributions to thermodynamics, steam engine theory, and civil engineering. The Rankine cycle — the theoretical model for steam power plants — is also named after him.
About Newton (N)
The Newton scale is an obsolete historical temperature scale proposed by Isaac Newton around 1701, predating both Celsius and Fahrenheit. It sets 0°N at the freezing point of water and 33°N at the boiling point — a 33-degree span. Newton chose 33 because it divides cleanly into thirds and twelfths, reflecting duodecimal arithmetic conventions of the time. Body temperature is approximately 12.2°N. Newton calibrated his scale using linseed oil as the thermometric fluid. His scale influenced later thermometrists but was never widely adopted and is today of primarily historical and educational interest, appearing in scientific history discussions and temperature conversion tools.
Body temperature (37°C) is approximately 12.2°N on Newton's scale. A warm summer day of 25°C equals about 8.25°N.
Etymology: Proposed by Isaac Newton (1643–1727) in his 1701 paper "Scala Graduum Caloris" (Scale of the Degrees of Heat), published anonymously in Philosophical Transactions. Newton used a linseed oil thermometer and calibrated it against the freezing point of water and body temperature, later extending it to a second reference at the boiling point.
Rankine – Frequently Asked Questions
What is the Rankine scale used for?
Rankine is used in US customary thermodynamic calculations where absolute temperature is needed but Fahrenheit-scale degrees are preferred. It appears in older American engineering standards for steam power, HVAC, and aerospace — disciplines where engineers needed an absolute scale compatible with Fahrenheit-unit formulas without converting to kelvin.
How does Rankine differ from kelvin?
Both start at absolute zero (0 K = 0°R), but their degree sizes differ. One kelvin equals 1.8 Rankine degrees, matching the 1.8 ratio between Celsius and Fahrenheit degree sizes. So 273.15 K = 491.67°R. To convert: °R = K × 1.8.
How do you convert Rankine to Celsius?
Divide by 1.8 to get kelvin, then subtract 273.15. Formula: °C = (°R / 1.8) − 273.15. For example, 491.67°R ÷ 1.8 = 273.15 K; 273.15 − 273.15 = 0°C. Alternatively: °C = (°R − 491.67) / 1.8.
What is absolute zero in Rankine?
Absolute zero is 0°R, the same as 0 K and −273.15°C (−459.67°F). Because Rankine starts at absolute zero, it has no negative values — a property shared with kelvin. This is what makes it useful in thermodynamics: equations requiring absolute temperature work directly without offset corrections.
Is Rankine still used in modern engineering?
Rankine use has declined significantly. Most modern engineering, including US aerospace and HVAC standards, has shifted to SI units (kelvin). Rankine persists mainly in legacy documents, some US university thermodynamics courses that teach both systems, and niche industries still working from older US customary standards. New engineering work rarely specifies Rankine.
Newton – Frequently Asked Questions
Who invented the Newton temperature scale?
Isaac Newton proposed the scale in 1701 in his paper "Scala Graduum Caloris", published anonymously in Philosophical Transactions of the Royal Society. He used a linseed oil thermometer and calibrated it against the freezing point of water and body temperature as fixed reference points.
What are the reference points of the Newton scale?
0°N is the freezing point of water and 33°N is the boiling point of water, giving a 33-degree range. Newton also used body temperature (approximately 12°N) and "the greatest summer heat" as intermediate calibration points. These are the same two endpoints used by later scales, just with different degree spans.
Why did Newton choose 33 degrees for boiling water?
Newton chose 33 because it factors neatly: 33 = 3 × 11, and one-third of 33 (11°N) corresponds approximately to body temperature in his calibration. The choice reflects his preference for divisions into thirds and twelfths, common in pre-metric scientific notation, rather than the decimal basis used by Celsius.
How does the Newton scale compare to Celsius?
Newton and Celsius share the same zero (freezing water = 0), but Newton's boiling point is 33°N versus 100°C. To convert: °N = °C × 33/100 (or × 0.33). Room temperature (20°C) is 6.6°N; body temperature (37°C) is 12.21°N.
Is the Newton temperature scale still used today?
No. The Newton scale was never widely adopted and fell out of use by the mid-18th century as Fahrenheit and Celsius became dominant. It survives today only in historical accounts of thermometry and in temperature conversion tools as an educational curiosity about the origins of quantitative temperature measurement.