Celsius (°C)

Definition

Celsius (°C) is a metric unit of temperature, part of the International System of Units (SI). It is defined by two fixed points: 0 °C is the temperature at which water freezes, and 100 °C is the temperature at which water boils at standard atmospheric pressure.

History

The Celsius scale was developed in 1742 by Swedish astronomer Anders Celsius. Initially, he defined 0 °C as the boiling point and 100 °C as the freezing point of water. This was later inverted by Carl Linnaeus. In 1954, the scale was officially adopted by the 9th General Conference on Weights and Measures.

Uses

Celsius is widely used in daily life, particularly in weather forecasts, cooking, and medical contexts. It is the standard temperature scale in most countries, except the United States, which primarily uses Fahrenheit.

Conversions

• To convert Celsius to Fahrenheit: (°F = (°C \times \frac{9}{5}) + 32)
• To convert Celsius to Kelvin: (K = °C + 273.15) (exact)

Fun Facts

• A common misconception is that 0 °C means "cold" and 100 °C means "hot"; both are relative to water's phase changes.
• The Celsius scale is sometimes referred to as centigrade, derived from the Latin "centum" (100) and "gradus" (steps).