Temperature Measurement Scales
Unlike other units that scale from a common zero point with simple multiplicative ratios, temperature scales utilize different zero reference points and different degree increments.
- Celsius (┬░C): Based on the freezing (0┬░C) and boiling (100┬░C) points of water at standard atmospheric pressure.
- Fahrenheit (┬░F): Widely used in the United States, placing the freezing point of water at 32┬░F and boiling point at 212┬░F.
- Kelvin (K): The thermodynamic SI base unit where 0 K represents Absolute Zero (ÔêÆ273.15┬░C).
Mathematical Formula
°F = (°C × 9/5) + 32
┬░C = (┬░F ÔêÆ 32) ├ù 5/9
K = ┬░C + 273.15
┬░C = (┬░F ÔêÆ 32) ├ù 5/9
K = ┬░C + 273.15
Step-by-Step Worked Example
To convert 68┬░F to Celsius:
1. Subtract 32: 68  32 = 36
2. Multiply by 5/9: 36 × (5 / 9) = 20°C.
Important Considerations & Limitations
Absolute Zero is 0 K (ÔêÆ273.15┬░C or ÔêÆ459.67┬░F). Temperatures below Absolute Zero are physically impossible under standard thermodynamic laws.
Authoritative References
NIST Temperature Measurement Reference Standards.