Temperature Calculator
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The history of temperature measurement is a fascinating journey through human innovation. Early attempts relied on subjective feelings of hot and cold until the 16th century when Galileo Galilei created the first thermoscope. The modern era of thermometry began with Gabriel Fahrenheit's mercury thermometer in the early 1700s, followed by Anders Celsius's centigrade scale in 1742. The Kelvin scale, introduced by William Thomson in 1848, revolutionized temperature measurement by establishing an absolute zero point.
Celsius to Fahrenheit: °F = (°C × 9/5) + 32
Fahrenheit to Celsius: °C = (°F - 32) × 5/9
Celsius to Kelvin: K = °C + 273.15
Kelvin to Celsius: °C = K - 273.15
Rankine: °R = (°C + 273.15) × 9/5
Réaumur: °Ré = °C × 0.8
Rømer: °Rø = (°C × 21/40) + 7.5
| Scale | Water Freezing | Water Boiling | Common Use |
|---|---|---|---|
| Celsius (°C) | 0°C | 100°C | Most countries |
| Fahrenheit (°F) | 32°F | 212°F | USA, territories |
| Kelvin (K) | 273.15K | 373.15K | Scientific use |
Different temperature scales were developed for different purposes and in different historical contexts. Celsius (°C) was designed around the freezing and boiling points of water (0°C and 100°C). Fahrenheit (°F) was based on a mixture of ice, water, and ammonium chloride (0°F) and average human body temperature (96°F, later adjusted). Kelvin (K) is an absolute scale starting at absolute zero (-273.15°C), making it useful for scientific calculations. Other scales like Rankine, Réaumur, and Rømer were developed for specific scientific or regional needs.
Absolute temperature scales (like Kelvin and Rankine) start at absolute zero, the theoretical lowest possible temperature where all molecular motion stops. These scales don't have negative values. Relative scales (like Celsius and Fahrenheit) are based on observable phenomena like water's freezing and boiling points, and can have negative values. Absolute scales are essential in scientific calculations because many physical laws work only with absolute temperatures. For example, the ideal gas law requires temperature in Kelvin.
Different temperature scales are preferred in different contexts: Celsius is used in most countries for daily life and scientific work; Fahrenheit is common in the US for weather and body temperature; Kelvin is standard in scientific calculations and international standards; Rankine is used in some engineering applications in the US. In scientific work, it's often necessary to convert between scales - for example, a chemical reaction might be measured in Celsius but calculations might need Kelvin for thermodynamic equations.