Three Different Starting Points
- Celsius (°C): Based on water (0 = freeze, 100 = boil).
- Fahrenheit (°F): Based on a mixture of ice, water, and salt (32 = freeze, 212 = boil).
- Kelvin (K): Based on Absolute Zero (0 K = where all molecular motion stops).
The Math
- °C to °F: (°C × 9/5) + 32
- °F to °C: (°F - 32) × 5/9
- °C to K: °C + 273.15
Why Kelvin?
Scientists use Kelvin because it's an "absolute" scale. You can't have "negative" Kelvin, which makes calculations for gas laws much simpler.
Key Takeaways
- -40 is the "cross-over" point where °C and °F are equal
- Standard room temperature is 20-25°C or 68-77°F
- Body temperature is 37°C or 98.6°F