To convert a temperature from Celsius (°C) to Delisle (°De), use this simple formula:

°De = \frac{3}{2} \times (100 - °C)

or equivalently,°De = 150 - \frac{3}{2} \times °C. The Delisle scale is unique because it starts at 150°De for water's freezing point (0°C) and goes down to 0°De at boiling (100°C).

Follow these steps for any conversion:

1. Subtract the Celsius temperature from 100:100 - °C.
2. Multiply the result by3/2(or 1.5).
3. The answer is your temperature in Delisle.

Example 1:Convert 20°C to Delisle.
100 - 20 = 80
80 × 1.5 = 120
So, 20°C = 120°De.

Example 2:Convert 50°C to Delisle.
100 - 50 = 50
50 × 1.5 = 75
So, 50°C = 75°De.

Quick tip:For temperatures near freezing (0°C), the Delisle reading is close to 150°De. As Celsius rises, Delisle drops quickly—remember to always subtract from 100 first to avoid mistakes!

Celsius

DefinitionThe Celsius scale measures temperature using the freezing and boiling points of water. Water freezes at 0°C and boils at 100°C under normal air pressure at sea level. Each degree represents an equal step in temperature change, making it easy to understand everyday weather or cooking needs.

History/OriginSwedish astronomer Anders Celsius created this scale in 1742. At first, he set boiling water at 0° and freezing at 100°, but scientists soon flipped it to the version we use today. This change made it more intuitive, as lower numbers match colder temperatures.

Current UseCelsius is the standard scale in most countries for daily life, science, and medicine. You'll see it on weather apps, thermometers, and in recipes worldwide, except in the United States where Fahrenheit is common. It's also the base for Kelvin in scientific work.

Delisle

DefinitionThe Delisle scale is an unusual temperature system where water boils at 0°De and freezes at 150°De. Unlike most scales, it gets higher numbers as temperatures drop, with each degree Delisle equal to two-thirds of a Celsius degree but in reverse.

History/OriginFrench astronomer Joseph-Nicolas Delisle introduced it in 1732 for precise observations in astronomy. He designed it to make cold temperatures have larger numbers, which helped in detailed measurements during his work in Russia and elsewhere.

Current UseThe Delisle scale is no longer used anywhere today. It was replaced by more practical scales like Celsius and has only historical value, appearing in old texts or as a fun example of how temperature scales have evolved.