Delisle to Celsius
°De
°C
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 °De (Delisle) → 99.3333333333333334 °C (Celsius) Just now |
Quick Reference Table (Delisle to Celsius)
| Delisle (°De) | Celsius (°C) |
|---|---|
| 0 | 100 |
| 94.5 | 37.0000000000000063 |
| 120 | 20.000000000000008 |
| 150 | 0.00000000000001 |
| 200 | -33.33333333333332 |
| 300 | -99.99999999999998 |
About Delisle (°De)
The Delisle scale (°De) is a historical temperature scale with an inverted direction: higher Delisle values mean colder temperatures. Created by French astronomer Joseph-Nicolas Delisle in 1732, it sets 0°De at the boiling point of water and counts upward as temperature falls; the freezing point is 150°De. This inversion arose because Delisle calibrated his mercury thermometer so that mercury contracted with cooling, measuring degrees of cooling from the boiling point rather than degrees of warmth above a cold reference. The scale was used extensively in Russia for most of the 18th century, notably by Mikhail Lomonosov, before being replaced by Celsius. Today it is an educational curiosity with no practical use.
Boiling water is 0°De; freezing is 150°De. A typical room at 20°C is 120°De. Absolute zero is approximately 559.73°De.
Etymology: Named after Joseph-Nicolas Delisle (1688–1768), a French astronomer who worked in St. Petersburg at the invitation of Peter the Great from 1726. He devised the scale in 1732 while in Russia, where it was adopted and remained in scientific use until the late 18th century when Celsius became standard.
About Celsius (°C)
Celsius (°C) is the most widely used temperature scale in the world, adopted by every country except the United States, Liberia, and Myanmar for everyday and scientific use. Zero degrees Celsius is defined as the freezing point of water at standard atmospheric pressure; 100°C is the boiling point. Originally called centigrade because of its 100-degree span between these two reference points, it was renamed Celsius in 1948 to honor Swedish astronomer Anders Celsius. It is the practical temperature scale for weather, cooking, medicine, and most scientific work outside thermodynamics. Body temperature is 37°C; a comfortable room is typically 20–22°C.
Water freezes at 0°C and boils at 100°C. Normal human body temperature is 37°C. A warm summer day in southern Europe is around 35°C.
Etymology: Named after Swedish astronomer Anders Celsius (1701–1744), who proposed a 100-degree scale in 1742. His original scale was inverted — 0°C meant boiling, 100°C meant freezing — and was reversed by fellow Swede Carl Linnaeus shortly after his death.
Delisle – Frequently Asked Questions
Why is the Delisle scale inverted?
Delisle calibrated his thermometer by observing how mercury contracted as it cooled from boiling water. He measured degrees of cooling rather than degrees of warmth — the scale counted how far the temperature had dropped from the boiling point. This made 0°De the starting reference (boiling) and larger numbers represent lower temperatures, the opposite of every other common scale.
What is the freezing point of water on the Delisle scale?
The freezing point of water is 150°De. The boiling point is 0°De. The scale spans 150 degrees between freezing and boiling — contrast with 100 degrees in Celsius or 180 degrees in Fahrenheit. To convert: °De = (100 − °C) × 1.5, so 0°C gives (100 − 0) × 1.5 = 150°De.
Who invented the Delisle scale and where was it used?
Joseph-Nicolas Delisle invented the scale in St. Petersburg in 1732, where he had been invited to work by Peter the Great. The scale was adopted by Russian scientists and used throughout the 18th century, particularly by Mikhail Lomonosov. It was later standardized by Joseph-Nicolas's colleague Joseph-Adam Braun, who fixed the two reference points.
How do you convert Delisle to Celsius?
Subtract the Delisle value from 100, then multiply by 2/3. Formula: °C = 100 − (°De × 2/3). For example, 150°De → 100 − (150 × 2/3) = 100 − 100 = 0°C (freezing). For 0°De → 100 − 0 = 100°C (boiling). Remember the scale is inverted: higher Delisle = colder temperature.
What other temperature scales run backwards like Delisle?
Delisle is the only well-known inverted temperature scale, but the concept appears elsewhere. Astronomical magnitude runs backwards (brighter stars have lower numbers). The Scoville scale for chilli heat is not inverted but is logarithmically compressed in a way that confuses people similarly. In thermometry, Delisle stands alone — every other scale (Celsius, Fahrenheit, Kelvin, Rankine, Newton, Rømer, Réaumur) increases with heat. The inversion made Delisle unintuitive, which is a key reason it lost out to Celsius.
Celsius – Frequently Asked Questions
Which countries use Celsius?
Almost every country in the world uses Celsius for everyday temperatures — weather forecasts, cooking, and body temperature. The United States, Liberia, and Myanmar are the principal exceptions, using Fahrenheit for daily life, though US scientists use Celsius for research.
What is absolute zero in Celsius?
Absolute zero — the theoretical minimum temperature where molecular motion effectively ceases — is −273.15°C. This corresponds to 0 K on the kelvin scale. It is not physically achievable but has been approached to within a few billionths of a degree in laboratory conditions.
How do you convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (or 1.8) and add 32. For example, 20°C × 1.8 + 32 = 68°F. A quick mental approximation: double the Celsius value and add 30 (gives ±2°F accuracy for typical weather temperatures).
What is normal body temperature in Celsius?
Normal human body temperature is approximately 37.0°C (98.6°F), though it varies by individual, time of day, and measurement site. A temperature above 38.0°C is generally considered a fever; hypothermia is diagnosed below 35.0°C.
What is the difference between Celsius and centigrade?
Centigrade is the old name for the same scale — both refer to a 100-degree span between water's freezing and boiling points ("centi" = 100, "grade" = step). The name was officially changed to Celsius in 1948 to avoid confusion with the angular unit also called "grade" (or "gradian") in some languages.